Thursday, 28 May 2020

Pandemic cycling and bicycle selection, going forward

Changed; 16/01/2021 - 20/01/2021

You never forget how to ride a bike.

 Thank you, Nicholas Bates (Facebook) for allowing me to use your photo

Nicholas's grandad said his bike was made by Colson - he referred to it as 'The Fairy Bike'.   I have previously heard of a "Fairy cycle" as a general term for a child's first bicycle.  "Hi Andrew.  It's black and white with added colour by me - I did a few for VE day to chart my Grandad from being a lad in the village through to the day he landed on the Normandy beaches and beyond.  The colour somehow made it more real - and more relatable for my own children.  Of course, you can use it for your blog. That'd be fantastic." 

That awful meaningless phrase "Going forward".  This blog intends to discuss different types of bicycle, share sources of tips and recommendations about bicycles and cycling.  The page also discusses changes that might come about as a consequence of the pandemic where people are cycling more but people are also worried about their financial security and the old hated being kept in.  Although the environment is very damaged by human activity species died, the climate changed but even in this short period big improvement in air quality is being enjoyed all over the world.  People are enjoying there own better health.

Check for loose parts and low-pressure tyres, pressing your thumb into the tyre as a quick guide before you start. 
Listen for rattles, rubbing noises and other changes, work out what they are and fix them on your bike.  
Look over your bike before moving off.

I plan to add more bicycle details at the present time this blog page discusses more of the other issues.
Experimental cycle lanes segregation in Tunbridge Wells.  This solution addresses the 
concerns new cyclist have about road safety following the lifting of the national lock-down.  
Update although criticised by car users the temporary plastic bollards also reminded car users not to cross into the lanes.  New cyclist reported they felt safer and personally I find that road better than it was 40 years ago before the new measures.  The bollards are now gone and cats eyes have been fitted.

Tunbridge wells had become very conjested with traffic 30 years ago so that vehicles could not travel through the town but now there are restrictions so that for vehicle's it is the same as 20 years ago but the town is improved by being less congested. The government under covid air quality and health measures have speeded up the measures and in some towns those measures were poorly designed and have been undone.  It is the nature of roads and towns that traffic management has always required planning studying and change continually and that the planners are often not listened to first due to public and interested party pressure.



Riding an adult bike for the first time;
Sit on the saddle don't pedal but scoot along using your feet on the ground. Some small children's bikes don't have pedals and are similar to 18th-century boneshakers in which the rider sits on and scoots the bike along.
  • Avoid dérailleur gears (or ask someone to select a gear for you then don't change gear) they are very distracting,
  • Chose either no gears bike but a hub gear bike is good (select 1st or 2nd gear if it is a three-speed or four-speed hub whilst moving the pedal a little, the bike can be stationary) it is very easy.  
  • A short wheelbase bike is easier to balance at low speed, such as mountain and folding bikes.  Long wheelbase bikes need more space to turn in and you need to be moving faster.
  • The Video; Put the pedal and pedal arms back on the bike (if you removed them) and carry on scooting then transfer your feet and pedal.  Finally set the saddle higher when you feel secure otherwise the bike will be hard to pedal.  Your front brake should be applied just before you apply the rear brake,  you should ensure most of your braking is at the front.
As easy as riding a bike -  Starting and stopping;
  • Simplest lean the bikes over then step over to form a wide triangle seated. Lift your pedal ready to push down whilst pushing off with the other foot. 
  • The video method works well with a step-through bike use the pedal to start moving and seat yourself. 
  • Put your outside foot on the pedal scooting off with your inside foot then swinging your leg overover, I have never used this method.
Long wheel base bikes move with less effort but need more of a push off to start. 
  • As easy as falling off a bike,  When stopping it is better to put your foot out wide and avoid putting your foot into a pot hole.

Riding a bike again after a long time; 
The next hurdle is to get your cycling strength up - just cycle up and down a road on a quiet day.  Doing no more than 200M then rest then repeat 200M, build up to 1KM over a number of weeks after that progress as you feel fit to. 
  • You should make up your mind in advance and start to manoeuvre early so that if you don't see what is behind you or don't manage to signal others on the road will see what you are doing in plenty of time.   Don't take your hands off the handlebars if to do so would make you unstable, such as the road has a bad surface ahead.  It is always better to push the bike on the pavement across a road junction or around a parked vehicle on a busy road with limited width.
  • Cycling on the pavement is fine if you take care and don't get caught.  The point is to put your foot down and stop or dismount if doing it worries pedestrians.  Cycle slowly on pavement even if you don't see anyone.  Modern policing mostly does not apply rules unless you are do harm.
  • Cyclists need to take their position on the road just the same as a motorbike user would be taught to or they/we will be driven into the kerb, broken glass or knocked off their bike.
Keep looking forward. Looking confident helps you feel confident and makes you safer. Give yourself plenty of space on the road don't cycle close to cars or the curb.  13-ways-increase-average-cycling-speed

Bicycle selection;
  • Differences between types of the bicycle;
    • Short wheelbase bicycle - mountain bikes very noticeably go in and out of all the bumps and take pedalling effort doing that.  You can turn sharply and move and manoeuvre at very low speeds.  A fun bike but more work to peddle and have a range of low to very low-speed gearing.  Some variants have higher speeds as well and others are much better bikes than the one pictured.  (Cheap Mountain bike pictured has [3 x 6] 18 gear dérailleur which provides 8 speeds, the bike is lightweight and sprung will protect the frame). This bike is not suitable for a heavy person.
    • Small wheel unisex, shopper and commuter bicycles - these are also short wheelbase and heavier to pedal if you try to travel at the speeds you would comfortably with a long wheelbase bike.  I guess you can balance easily at a lower speed than a long wheelbase bike so if you have one of those bikes and my guess is that you should not need to or expect to go anywhere quickly.  You can carry lots of shopping and move faster than walking.  [This paragraph needs observation to be checked]
      • The step-thru bicycle pictured (Astra made and imported in about 1985) is a good all-around bicycle.   Particularly because you can mount and dismount easily.  Step-thru bikes are heavier than bikes with a cross-bar.  These bicycles have a longer wheelbase which makes them a lot lighter to pedal.  This Soviet-era high tensile steel frame bike is lighter weight than a conventional steel frame bike at 15.5Kg.
      • Modern town bicycles - these also have greased bearings like the other modern bicycles.  The hub gears make gear changing very easy when stationary or moving so they are not a distraction when cycling on roads.  (The Astra pictured has a thin oil lubricated, 3-speed Sturmey-Archer AW hub made in England which is known for its robustness)
          • Bikes made before the late 1970s (I am advised) have a longer wheelbase makes the bike seem to fly over the bumps rather than go in out of them.  The increased length of the bike is small but the benefit is amazing (it is said).  You see a bump, feel the bump in your arms and have a moment to transfer your weight from the saddle to the pedals.  The flexibility in the Reynolds 531 steel frame in the Lenton pictured also contributes the lightness, smoothness of the ride and as well as giving the bike a very liked "alive" feel and light to pedal.  The wheel hubs are also thin-oil lubricated making these bikes transmission very efficient.  -- Longer Wheelbase mountain bikes are starting to come back again, I am advised.   Others also say bikes made before 1970 are better.
          • Pre-1961 bicycles are the lowest or comparable friction to any modern superbike the crank is also thin-oil lubricated but can be greased.  In addition, they have a long wheelbase which makes these bikes feel wow this bike seems to be helping me go along but hills are hills and spokes also break occasionally;   1946 Raleigh Lenton sports pictured cleaned with linseed oil, patched such as the bottle top for a pedal cap that I had crossed the thread on as a boy.  The low left-hand side lamp that shines into the gutter allows you to see hazards in the kerb when cycling in the dark.
        The gearing on the bike, high tensile steel frame and the long wheel base make the bike lighter, smoother as you go up the gears and go faster.  As if the frame were highly tuned.
          • Modern superbikes -  many people have an old lightweight high tensile steel frame sports bike and a modern lightweight such as a carbon fibre frame bicycle.  These superbikes and old bikes also have low friction ceramic comparable to the old thin-oil lubricated bearings on bikes made before 1961.   The old sports bikes corner much faster but are more wobbly at very low speed than some modern regular bikes. Many people like both many others say the much older bike is lighter to pedal and is better others say the newer bike will be 3-5Km/Hr. faster.  I believe this is true of some bikes made after 1890 and all hub geared bikes 1920 to 1961, these sports bikes are low, long and Raleigh's engineering was excellent during this period. [Comparison a competitive sports cyclist may start the day with a hearty fried breakfast, smoke before competing in the past but that is unlikely now]
          • The rack and the rear and panniers are good and stable.  It is best to avoid carrying any weight in a front basket. Alternatively, a front basket that is mounted so that it does not turn as you steer is more stable, I am advised. 
        • Pedals - metal types are better because they don't slip so easily as rubber pedals.  I have not ridden a bike with toe clips they scare me and I am advised that people do fall over with them.  My father used toe clips and a cycling cape with the Lenton sports pictured.

        • All bicycles are helped a lot by having gears either hub gears or the cheaper dérailleur gears.  Wide spacing gears for general use but medium or closer spacing gears are liked for sporting use so the cyclist can maintain his cadence.  Hub gears cater to both requirements but also allow gears to be changed when the bicycle is stationary.  Both British made elliptical gears and dérailleur gears have comparable efficiency but the hub gear is much more robust.  (Pictured; Bike stand so that dérailleur gears can be adjusted made from a second-hand car bike rack)
          • Some modern mountain bicycles have the gears in the crank (bottom bracket) with helical cut cogs for quietness and efficiency otherwise these are not new and here is a link to a 1937 Helvetica bicycle.  All the power is transferred by cogs to a lay-shaft then back the main shaft using cogs.  By comparison, only a fraction of the power is carried through the cogs in bicycle elliptical gears achieving good efficiency.   There have been a number of bottom bracket elliptical gears such as Dana USA but I don't know of a modern equivalent?  These are mostly heavier, less robust or less efficient than a British made Sturmey-Archer type hub gears. 
          • Generally, derailleur gears are close or medium spaced but wide spacing achieved by having many gears (Up to about 15% spacing compared to an AW 3-speed hub which has 33% spacing).  But it is possible to have widely-spaced derailleur gears but with poorer shifting.  Note derailleur gears are also called Disraeli gears.
        • Where the modern aluminium alloy or carbon fibre bicycles score is that they are lighter to carry and take on a train for example.  But only steel or high tensile steel and brazed lapped joint frame bikes have a reputation for not cracking or corroding.
        • Where most modern bikes score is they require less maintenance but the cost is that they don't last long.  They cost more to purchase or are so cheap and poorly made that they disappoint the cyclist.  Many new bicycles get very little use in any case. 
        I don't have the personal experience of many bicycle types but I have reference such as the video shows you how to set up a bikes Rod and Stirrup brakes.

        I recommend the amateur videos made by Velocipedium on YouTube.  They take care to show you how to maintain and enjoy a bicycle.  Even if you are not a starter do watch the videos anyway.  I had a bike with Rod and Stirrup brakes when I was a boy and I have replaced the brake blocks on the bike in the 1960s, I don't think you could still buy just the rubber part?  I have also bent calliper slightly as shown on my Lenton Sports cable and calliper type brakes to align the brake block that had always been slightly out of alignment tending to ware one block one end more than the other.

        Covid-19 a cartoon below circulating at the time that the lock-down started to be lifted in May 2020;

        Picture left Southborough 4th July 2020; 
        First day that cafes and pubs can serve sit down, eat and drink food since 20th March.

        It looks like Government thought the NHS was fine despite a decade of austerity then people in government got ill themselves and got scared.   The less important ill were kept out of hospitals sent home in case the more important people got ill.  Now people can visit a hospital but many have been scared or are staying away.
        By comparison Germany and northern parts of Europe had capacity in their health systems but took a varying degree of cautious approach and have coped better.  Sweden trusted their people but brought in measures as they became necessary in a measured way.  Sweden and all these countries will probably come through with the best outcome, that is that the people feeling most satisfied the best was done.

        USA's health systems only look after those who can pay and ill people who don't have money would die anyway.  Of cause, southern and northern states are quite different and each state has there own policies.

        The cartoon expresses the sort of concerns people have on the lifting of locked-down.  The government is managing the lifting of lock-down by manipulation and retraction thereby creating annoyance but as required slower return to normal or a new normal.  Fortunately "Social distancing" is not occurring but people are talking to each other and enjoying there families at a safe distance.

        Picture left; Barnett's Wood Nature Reserve, April to July 2020
        People enjoying nature, home cooking, cycling, social media, their children instead of work, cafes, consumption and shopping. 

        Momentum Labour at the last General Election, in December 2019, offered a path of social responsibility.  The government offered to promote peace in the world, the environment and toward each other.  Different from both New Labour and Old Labour, in not promoting self-interest.  I was very surprised that Momentum Labour captured so much support.  Momentum Labour's modernised 1945 Manifesto was very inspiring and I expect that Coronavirus would have been handled differently.

        The Iconic CND symbol - Designed for the Campaign for Nuclear Disarmament can 
        be used freely and is made up of the semaphore for "N" and "D" (Nuclear, Disarm).

        The Victorians built sanitation system in order to protect the rich from catching a disease from the poor.  Cricket and sport encouraged for the health of all.  But I doubt that the vastly rich will impose health, better food, air, cycling on us, this time but in order to save the planet from the adverse consequences of human activity. 

        Government promotes cleaner air, better health and bicycling
        There are others who promote zero movement and zero international transport and forced isolation China style, I believe?  
        And everyone is sceptical of business interest, Gates foundation in the 3rd world and policies of population reduction.

        I have had enough of being playing by the media (called politics), people set against each other - I'm going to ride a bike;

        Time will tell but I hope people do not become reliant on big pharma and disinfectant for a sort of living instead I wish we all learn to like good health and much less waste as a way of life.  There be less reliance on factory-farmed meat and more plant-based food.  A high correlation between poor air quality (such as in cities) and Covid-19 fatalities but vehicle emissions and crashes is the major cost to the National Health Service.  I hope people change their minds about cars.

        During this Covid-19 pandemic, people have been cycling more and enjoying better health due to the better air quality whilst road traffic has been greatly reduced.  Poor air quality in cities has been strongly linked too poor respiratory health long before the clean air act of 1956 and poorer survival to Covid-19.

        More Cycling
        This Astra bike (pictured above), which I purchased locally cheaply,  now has lights and reflectors.  It also has new tyres, all re-greased and running nicely.  The bike is easy to maintain and fully service and the bikes cost so far have been about £90.  The Astra imported from Czechoslovakia or Yugoslavia badged England and sold in the 1985 (the date on the Sturmey-Archer, England, 3-speed hub) The rims are German and the frame is a nice lightweight Soviet high tensile strength steel. [this paragraph to be replaced by other bikes]

        A rose, The De-La-Warr Pavillion, Bexhill-on-Sea, East Sussex.  Built by the Socialist Town Mayor, Earl De-La-Warr in 1935
        This building is one of the most beautiful architecture anywhere.  I can not be captured on film and I have not seen a picture
        that captures the impression that the building has now or had before its renovation.

        The pictures above were taken on a Canon AE1, using Fuji Slide film.  The best amateur camera of its time, 1976.

        The pleasure of owning an old bicycle;

        Many people run an old bicycle those bikes were made to work hard for a very long time and must be maintained regularly.  This bike is has been nicely kept and has a secret conversion to E-bike.  A lot of bikes run and look lovely just as they are but for being maintained and the frame cleaned with an oily rag or linseed oil.  Other bikes are brought back to almost new with detail restored and artisan finishes as well.

        Raleigh bicycle maker of Britain was once the biggest manufactured of bicycles in the world, representing the best in engineering.  British engineering, textiles and film industry were for a long time second to none.  Statutes to war leaders and heroes, slaver traders, bankers and the city of London are good representations of the country.  Perhaps the most prominently placed statue should be a heron to mark 125 years (1887-2012) that Raleigh existed in Britain and looking forward to cycling, walking, cleaner air, better health and kindness towards each other and harmony with nature.

        Like so many things The Mallard, Pacific A4 class locomotive distinctively beautiful because of its typically British understated design style by the British engineer Sir Nigel Gresley.  Along with the Flying Scotsman, A3 class were the fastest surface public transport in the world.  Although by the 1920s and '30s trains could now be made to be very reliable, but they were not efficient or clean.  At this time bicycles were as good as they were ever going to get.

        Electric trains started to be introduced on a substantial scale in the 1920s in South East England.  This region has the highest density rail network in the UK.  After World War two faster cleaner diesel and electric trains started to introduced all over the country.  Electrification of the rail network is still ongoing. 

        Old lessons have to be relearned by a subsequent generation of engineers; There are many subtle design features in machines that are not apparent until the designers have left.  A change to a design makes it apparent that there were important design features.  Each telephone made until about 1985 had a low pitch bell and each bell had a different pitch.  The low pitch telephone bell in an office made it easy to tell where the phone is and the different pitch if it was your phone.  The same mistake was made when the two-tone ambulance klaxon was replaced in the 1980's.  I suppose it is possible that the shortening of bicycles wheelbase that occurred in the 1970's, making bikes more work to pedal happened by accident but more likely happened with arguments where the arts farts case won?

        Newer hub gear designs;

        The Rohloff hub weighs 1.7Kg, British made Sturmey-Archer Hub gears weigh 1 to 1.4Kg but most hub gears weigh 1 to 2Kg.  But despite the long power train higher efficiency has been measured but other studies don't rate this hub's efficency highly.  It has 14 speeds but as with bicycle elliptical gears, only a percentage of the power is carried through the meshing cogs, which is why bicycle elliptical gears are efficient.  The spacing between speeds (13.6%) is similar to a medium ratio Sturmey-Archer hub.  None of the speeds are high efficiency but also the high ratios are surprisingly good - on paper.  By comparison, the vintage Sturmey-Archer FW is highly efficient in Normal (3 of 4), when its most apreciated and Bottom the least efficient highest ratio is not heavy when hill climbing when the efficenty is least noticed.

        Very typically German engineering design.  The design is an assembly of simpler functions blocks built up.  The first part of the video shows a Sturmey-Archer hub its design much more like a complex single function block where parts slide and move changing many things as they move.   The Sturmey-Archer design is typical of British design being elegant robust and cost-effective.  The design is simpler also because of the limitations of the time 1902 but in 1973 the s7, 7-speed hub used a rotating operating rod in which cams operate a different section of the hub was introduced.

        The advantage that fewer speeds is that the cable operation is reliable if higher or lower speeds were required with the old bikes you can unscrew the large sprocket and change the chain (see picture left). A complaint about modern bikes is that not all gear work and some bikes are difficult to set up.  The Rohloff Speed hub above resolves the indexing issue by placing the indexing mechanism within the hub.

        Pictures - The Riley 9 car (1930s) was fitted with a Wilson preselector gearbox.  This is an elliptical gear gearbox with friction clutches that operate selectively on the ring gears.  Otherwise, this type of gearbox is different from a bicycle gear hub having just one speed for each elliptical gear.  The gear oil should be changed every 3,000 miles but the oil-bathed friction bands need re-lining after at least 160,000 miles.

        The Wilson gearbox is very heavy to operate due to the effort operating the clutches but more modern power assited preselector gearboxes are lighter to operate.

        Willson preselector gearbox gear change can be operated stationary, moving or powered.  I have seen a video of bicycle gearing that does that based on elliptical gears Constantly variable planetary but the power direction is reversed and it is unlikely to be efficient.  Daff/Volvo varomatic and moblette moped V-belt drive automatic gearing are fairly efficient and this variation called Inception Drive probably is efficient.  With an additional no-slip between speeds feature added using freewheel mechanism on the lowest speed, perhaps another bicycle crank gear could be developed based on a Wilson pre-selector with friction bands.  This solution is likely to be big and heavy to operate.  The variable speed elliptical gear hub patented 118 years is very good and the variants developed by 1960 covered most things required.

        During the Coronavirus lock-down 2020 there was a big reduction in vehicle movements  I first noticed that my breathing improved between mid-March to the end of May when the traffic came back on the roads.  Also that my Tinnitus diminished greatly and quickly when I stopped drinking coffee;

        I hope for more kindness in the world.  UN Secretary-General's Appeal for Global Ceasefire during this pandemic;

        Cycling is a good exercise in that you can work hard then rest on the flat, particularly so on a 4-speed hub gear bike made before 1961.  You are not pounding sore feet and ankles on the ground.   In this respect, a bike that is at least 45 years old or is one of the newer long wheelbase bikes, with ceramic bearings coming is probably better.  You can still get off and push and also lift the bike onto a train.  Also, you tend to have higher peaks of effort than walking or e-biking which is good for reducing high blood pressure,  the Doctor tells me.

        I recommend you understand your bicycle so, therefore, carry out your own maintenance.   Cars, bikes and motorbikes all used to be easily maintainable - I have posted some pictures of some 1930s to 1950s publications below.  These are very comprehensive some have a cover price some were available on request such as Car Care from CC Wakefield Ltd. London the manufactures of Castrol oils.  Two colour lubrication diagrams for any car on were also available on request, for example.


        Envisioning a post-Covid-19 transport landscape: surface travel
        Prof John Whitelegg, Liverpool John Moores University, looks at how The UK can transition to a sustainable transport system by building on some of the changes pursued during the Covid-19 ‘lockdown’. In the first of two blogs, he focuses on surface travel.

        The carbon footprint of British military spending is a level is similar to the emissions produced by over six million average UK cars;

        The military-industrial complex becomes a useless liability in the pandemic;

        If we don't look after the natural environment we will get unwell

        Sweden, light touch Coronavirus measures - May 2020

        Kent County Council - Learn to ride, Cycle training for children or adult;

        Department of Transport - Bikeabilty

        Cyclecraft by John Franklin (ISBN: 978-0-11-708243-4) - has been recommended.

        Active Travel - package of funding announced by Government during the Covid-19 pandemic;

        Transport and environment after the COVID lockdown
        To Tunbridge Wells Borough Council - requires login

        The Highway Code;

        The bicycling museums all over the world here are a few;

        Facebook - Disraeli Gears

        Facebook - Vintage bicycles UK

        Facebook - Raleigh Lenton and all the derivatives

        Facebook - Vintage Raleigh Bikes

        Facebook - The Raleigh Roadster Club. (Incorporating the Raleigh Superbe Owners Club)

        There are very many other cycling groups on Facebook but many bicycle brands were owned by Raleigh which in turn merged with Tube Investments.  Many of the bicycle groups on Facebook have document sections with good descriptions on how to do things.

        Picture; Brokes Wood - Informal BMX bike track
        now closed to the public by the present landowner.
        Reference given to me for wide the widest dérailleur you will find are modern
        1x systems. E.g. sram 10-50 12 speed cassette. This has a range of 500% with a spacing of about 15% between speeds.

        Sometimes it is necessary to buy a specialist tool in that case here is a US company with some useful tools (I have not used this company);

        Video right; A press tool like the one shown is also the best way to remove and put back the cotter pin. It is not just needed for a bike in poor condition. I've used a vice and a socket or ring spanner successfully. Don't hammer a cotter pin or tighten the nut too much but use the press because the metal is soft.

        More Bike Advice;
        Bike parts; Some bike shops can advise and supply but if you know what you want then
        SJS cycles supply parts efficiently.

        I am also told Laura Wakefield can supply parts that are not made anymore.
        Many people including can be found on many of the Facebook bike groups who paint, restore, sells head badges and hub-gear parts.  One of those members for example also dates bikes made by Raleigh.

        Other links;
        Story of my Lenton sports bicycle + General maintenance advice, technical and history;

        Dynamo maintenance and operation in theory (untested)

        Sunday, 8 December 2019

        Tunbridge Wells Constituency General Elections 1885-2019

        I don't know if Tunbridge Wells has always had a Conservative or a Unionist MP but it has been at least since 1885, except for 1906.  Until 1910 the Liberal Party came a close second or won in 1906 and during the 1950s the Labour Party also came close to winning the seat.  From the 1980s until 2010 Lib-Dems had been second but they have moved to 3rd or 4th place whilst the Labour Party had been gaining ground again since the end of the 1980s.

        The 2019 General Election timing was chosen by the Conservative prime minister for best advantage for that party, with help of the Lib-Dem leader and despite having fixed term parliaments.  Generally, electors rejecting coalition of any sort despite, Michael Heseltine, John Major, Tony Blair and others recommending something like that.   Locally the Lib-Dem's gained by heavy leafleting (the number of trees lost did not count against them) despite the usual trend but Labour fielded a candidate with an out of the constituency address.

        There was a short time when Conservatives did not run Tunbridge Wells Borough Council and Kent County Council in the 1990s.  You can also see the inevitable downward trend in Labour voting in General Elections when Labour was in power this effect is not apparent in Conservative voting in general elections.  Conservatives vote for other party's some making a point of voting Labour in local elections when they don't like what their party is doing nationally.  Also in Local Elections from 1990 Labour followed an upward trend but in General elections the trend fitted the pattern I suggested and the trend was downward whilst Labour was in government.

        Observations from looking at the data and discussion;

        Before WW1 - General Elections probably happened when members chose to step aside.  So there was a more gradual change - the system seemed fairer but that the franchise was only for men with property. 

        We could do with both the franchise widened plus that voters all getting to vote without problems.  We could do with the media to behave better or be shut down completely.  I am sure people feel they got it wrong because they listen to the media so don't vote next time.  

        The 2019 election;

        Conservatives have been winning elections for the past 30 years by promising to leave the EU to a minority but not delivering that promise.  This has been a good strategy for them because their is no other party likely to carry out leave.

        Even if we never have another Labour government.  Momentum, Jeremy Corbyn and his team have inspired a considerable number of people to get into politics for the good.   People of an alternative viewpoints voted who have never voted in 40 years.   The Labour opposition have high success rate in opposing successfully many of the a very nasty party's measures.   That nasty party could not change but instead beat its own MPs in to line.  Perhaps even Mrs May wanted change but there were Conservatives who said the last 40 years were a mistake - in this election campaign.  That has been said across party's for a few decades.

        Lib-Dem leader gave this election to the Conservatives by letting them chose when it wanted an election.  Of cause the Conservative government chose before Brexit so that Leave campaign did much of the work.  The outcome though is that all party's followed Labour's look after the little people promises in there manifesto's.  Still I am not expecting Boris Johnson to be a Socialist in Wolves clothing?

        Mistake of the environmental campaign in the 1990s may now be overcome;

        The Campaign for Nuclear Disarmament were very effective taking care not to divide amongst themselves on strategy.  The old guard from the 1960s guided new member's well from 1979 when Cruise Missiles and Theatre nuclear war was being deployed for in the UK and Europe.  In the 1990's the environmental groups divided and criticise strategy's.  They employed advocates rather than environmentalists and activists.  The environment, social rights and other things than self interest have started to inspire more young adults again.  

        Presentation prepared for; Extinction Rebellion London University's Strand the Strand event in September 2019 that was broken up by the police. Based professor Keith Barnham's book, The Burning Answer;

        The young people must not give up - they share the same enthusiasm that people now over 85  had in 1945.  The 2019 Labour Manifesto was more easily achievable and exciting however they voted.  The manifesto did not have the an anti-nuclear war policy that the 1980s Labour manifestos had despite that policy having been supported now by the public for the past 20 years.


        1885-1910 Tunbridge constituency;

        1916 No general election due to World War 1.  Term reduced to 5 years.

        1918-1970 Tonbridge Constituency.  Franchise widened to Women and people without property.

        1974-2018 (present) Tunbridge Wells Constituency

        BBC 2019 election results.

        Turn out percentage for 1956 found in a government document found on the web.  The figure looks correct for the given the poll.

        Post General Election Momentum and The Labour Party - this video might be deleted?

        Pre-election warning - I am in any-case very surprised out how well Labour and Momentum did inspiring people mostly younger voters but also voters over age 85 who remember how it was before the NHS.   Those now very old voters liked the manifesto seeing simply a 1945 Labour manifesto.

        Thursday, 18 July 2019

        Bicycle Hub Dynamo maintenance

            Changed; 23/03/2021 to 25/03/2021

        Pictured; Sturmey-Archer, AG - 3-speed dyno-hub, dated July 1953;  
        3-speed wide variable gear hub and 6V, 2W generator.  40 spoke.

        The first impression - the sprocket turns both directions without engaging and was floppy but after dismantling, reassembling and lubricating the gear hub is free running, it should feel loose which it does.  The case is bright chrome with some rust and the internals seen from the outside are dirty black dry oily and dry inside.  It has not been oiled adequately probably not assembled correctly and the toggle chain is missing - this dyno-hub's condition is unknown.

        The dynamo - feels dirty but does not feel like there is any internal rubbing.  Turning the dynamo is definitely lumpy as would be expected as the poles line up but the magnetic force is quite high - which could mean the winding is shorted and/or the magnet is in a very good state of magnetism.   To be correct it is not a dynamo because it does not have a commutator, brushes and therefore produce direct current but it is a single-phase permanent magnet (alternating current) generator. 

        Once the terminals were tightened there was good continuity.  Shorting the contacts makes the magnet detent force stronger (harder to over come) as should happen and indicates that the winding is not shorted. That is as far as I can tell over the friction from internal dirt at first but now that everything is put back together properly, lubricated the hub runs fine and appears to be in good order.

        On opening the dynamo it becomes apparent that the magnetism is not particularly strong and it is quite easy to slide the winding assembly against the magnet.  The magnet is old for the time, probably AlNiCo type that would never have been particularly strong.  The air gap, as expected, is large by modern standards of motors and generators but that is because it uses the same high side-thrust weight carrying bearings as the wheel this lowers the dynamo's power a lot.  It turns out that the magnet was not fully magnetised but probably magnetised using a calibration procedure in order to set the required output current.

        Pictured above right;  Stronger ceramic/ferrite type magnet from a 1950s or early 60s TV.

        Summary - Mechanically the Dynohub was made like all Sturmey-Archer / Raleigh products of good quality materials, to be easily maintained and serviced over its almost indefinite life span.   I have read that Sturmey-Archer hubs were sold with a 50 year guarantee in 1950.

        To discuss the electrical issue with some textbook motor and generator theory.   All so-called bicycle dynamos are really alternating current generators they have no brushes and they are identical to many electro-mechanical mains voltage timers motors such as used to be used in central heating timers.  Some such as a hybrid stepper motor have two (four), three or five phases and operate at low speed.  This type of motor or generator is called a single phase permanent magnet synchronous motor or generator.

        Two appendices at the bottom of this page;  
        • A bicycle dynamo light and battery manager with a speedometer design idea.  It interfaces by USB cable.  
        • There is some reference to magnetism,  motors as generators.
        Graph - Expected current can be drawn up to the same limit irrespectively of the generator speed and then the 
        voltage will drop sharply.  There are other factors and the voltage drops as the current increases in the real dynamo.
        Small graph - With no load, the output voltage increases linearly proportionally to the speed of rotation.
        Lightly loaded the dynamo is the same as a tachometer and would make a good speedometer. 

        In a discussion on Facebook, I have been shown the patent below which claims a method of providing some voltage regulation rather than current regulation that I suggest above - load voltage regulation is claimed.  The magnet is machined in a way to form discrete poles so that the magnetism does not slip around and presumably be weakened more quickly.  The claim is also that the current reaches the desired level quickly - That would occur in any case by having a lot of poles and a high number of turns/volts coil.  The graphs with the patent do show some voltage regulation when loaded.  The description also mentions reactance of the winding being a limiting/regulating factor but I am not sure how this helps to model a generator?

        The patent is dated 1936 - I found it difficult to understand.  I would appreciate your comment below.

        Tests below show that after re-magnetisation that the dynamo behaves as a fairly constant current source and the open-circuit voltage output increases with speed.  Therefore the diagrams are roughly correct V.
        The losses in the dynamo are due to;
        • Bearing friction which is very small in the case of a thin oiled bearing.
        • Magnetising force - the power needed to change the magnetism polarity in the iron conducting the magnetism to the winding this is very small and might be 1% of the maximum power available for the given frequency which can be determined by looking at the B-H curve for the material.
        • Eddie currents in the iron conducting the changing magnetism this depends on how thinly it is laminate.  This looks fairly lossy because the metal is not thinly laminated but is just three laminations.
        • Copper losses are the losses due to the resistance of the winding when current is drawn either into a lamp or a short circuit and are;  I2*R which is; 0.45W = 0.32 x 5 in this case.
        Magnet keeper to prevent demagnetising - if required;
        The magnet will demagnetise if separated from the armature so if you remove the armature you need to replace it with a keeper such as another armature.  A magnet keeper is a piece of soft iron that conducts magnetism very efficiently.  Mu-metal that transformers,  motors, generators and the screen on an old colour TV Cathode Ray Tube use are ideal.  The metal should not be bent or hammered because this hardens the metal and reduces the metal's desired qualities so you should minimise the amount of work you do on the metal.

         Colour TV, Cathode Ray Tube magnetic screening is made of mu-metal.  Microwave oven transformer
        with high leakage inductance - pictured left.  Single-phase shaded pole induction motor - pictured right. 

        Mains frequency transformers come apart into a bobbin with valuable copper wire, "E" and "I" section mu-metal.  I suggest cutting the mu-metal into strips and sticking it to some sticky tape end to end and side by side.  The microwave oven transformer with high leakage inductance pictured is welded and will probably be difficult to take apart, therefore look for another transformer.  Very old mains and loudspeaker transformers are not varnished so come apart easily for example.

        The motor's mu-metal will need some more cutting to make it useful.

        The Plan to make a keeper - if required;
        To cut a piece of mu-metal and carefully bend it into a radius.  In more detail like a C shape but with the ends overlapping.  I had planned to make the metal strip with one end folded up so it could be pulled out but the magnet turns out not to be as strong as I was expecting.

        The estimate of the dimensions from outside dimensions;
        • BSA and others - many sizes not known. 
        • Sturmey-Archer
          • GH12 (1937-44), 111mm outside diameter (from pictures). 12V, 2.7W and 3W
          • GH8 (1939-44), 90mm OD (from pictures), 8V, 1.2W
          • GH6 hub dynamo (1944 - 83), AG and FG variable gear hub-dynamos.  6V, 2W (reduced to 1.8W subsequently I believe).
            • Estimate magnet internal diameter measuring inside the bolts is; 70mm. and width 24mm
            • The length required of mu-metal required is the circumference;  210mm = pi.D.
            • Therefore ensure there is at least 230 x 30mm mu-metal
        I understand that all post-world war two Sturmey-Archer dyno-hubs and gear dyno hubs are the same and parts interchangeable.  The external appearance changed from time-to-time though.

        Picture - Making the keeper;  Find a glass jar of about the right diameter,
        wrapping it in a rage then bending the mu-metal around the jar.
        The kitchen scissors are described as cut anything up to tin plate and
        are more suitable than the tin snips on the right.  A hammer, anvil
        (use a vice with care) and a file to clean up the cut edges.

        I have some mu-metal and have cut a piece 30mm x 260mm x 0.5mm - it looks messy because I used kitchen scissors and it would be better cut with a guillotine to make a magnet keeper for a GH12 hub-dynamo. My plan is to carefully bend into a C shape radius. 

        The variable hub gear and other bicycle parts are made to loose tolerances so that no moving parts should feel stiff or tight.  That is they tolerate grit and dirt with the minimum of harm wear.  The frequent oiling is necessary to lubricate and to flush out dirt.

        By comparison the synchro and servo, gear-heads and tacho or syncro resolver pictured right are expensive precision components used in precision instruments.  There is virtually no slack or stiffness in them.  They were supplied in the tightly fitting plastic pack shown and were made in the 1960s by Vartec.  These components can be stacked end to end and they fit firmly.  Synchros and servos must be used in a clean and dry environment.
        Syncros and servos were developed for use to calculate gun ranging during World War 2 one of the lectures at college I attended was one of those war times boffins who worked on gun ranging.

        Disassembly of the dynamo section;
        The magnet is brittle and is pressed into a soft metal enclosure with water excluding lip.  There is also a cardboard washer protector shown with intellectual property details printed on it.  It is not necessary to move the wiring and it is best avoided doing that unless there is an issue with continuity or insulation.

        A dynamo hub bearings and the variable gears can be serviced without separating the magnetic parts.  In this case, the magnet moves around the winding freely and the inside looks clean enough so a keeper may not be required.  Although the amount of cleaning will be limited either way.

        I have used a mole wrench to hold the shaft by the not threaded flat sides, a 15mm ring spanner for the nuts on the shaft, and a 5mm nut-spinner for the 8BA nuts that hold the dynamo section together (the 5mm socket I have is too fat).  The magnet has 20 poles in this picture.

        I have wiped to clean the surfaces then rubbed them all with grease.  I have also pushed the coil a little way out of the magnet it moves too easily it should be difficult to move, indicating that the magnet has weakened over time.

        The bearing can be seen the adjustment can be made from inside or also the adjustment can be made with the dynamo section assembled using the remote adjuster picture on the bottom left corner of the tray of parts.   If you are not going to touch the gears section it is probably best not to touch this bearing or the remote adjuster.  (In this case, the bearing and the bearing the other side does need grease and therefore adjustment otherwise oil gets to the bigger bearing inside and other parts).
        Note that the GH6 front wheel fitted type hub dynamo bearing adjustment is carried out from the non-dynamo side.  See;

        Inspecting the variable gear section bearings, greased and adjusting;
        Video shows AW hub disassembly and that the drive side bearing is set to 1/4 to 1/2 turn slack and the non-drive side is set after the drive side bearing to 1/4 turn of slack.  There are some differences and I have shown a tray of parts for the dyno-hub with the dynamo side bearing disassembled.

        One difference with the variable gear only hub - There is no press-fitting bearing oil trap so that a little lubrication from the variable gear will spread into the dynamo section.  The rust seen in the picture is a little greasy.   The hub should not be greased other than a little to hold the balls in place so that it can be assembled.  This is a little different to the advice given in many videos.

        Note; It turns out that variable gear is complete and disassembly and assembly is straightforward.  Do use the video or other sources for maintenance information.  You should not need to disassemble as far as the video shows you but also look at the planetary gears for timing marks an AG or AW does not have them but some variable gear hubs do and they must all be aligned when you re-assemble the hub. 

        Picture right; Broken old type indicator rod and toggle chain from an FW variable gear hub.  The indicator rod will fly out if you simply unscrew the toggle chain on hub made up until about 1950.  On such an older hub with an indicator rod unscrew the indicator rod so that the toggle chain the other side can slide out.

        There is one spacer between the drive sprocket and the variable gear but the video above shows two spacers and it is important to put them back as they were found.  The sprocket needed to be put back the other way like the video and another bike that I have.  In conclusion, if this dynamo were to be used on another bike the location of the spacer or spacers would need to be reviewed.

        I was able to test the function of the variable gear by screwing an old thread type thin 1.5mm spoke into the toggle chain place and see that the variable gear operates properly.  The dynamo and gears have not been road-tested on a bicycle.

        Magnet keeper - if required;
        You can push the keeper or another winding, as a keeper, in from one side and thereby push the existing winding out for inspection and cleaning.  See TEST 4 below if you need to take this step which shows a procedure and measured outcome.


        Testing the dynamo;

         1. With the bike wheel off the ground so that it can be spun freely;
        • GH 12 - I believe the circuit is two 6V filament lamps in series rated at 150 mA.  Short one lamp to see if the other lamp illuminates then short the other lamp this will determine if there is a simple lamp failure.
        • GH 8  - I believe the circuit is two 4V filament lamps in series rated at 250 mA.  If the circuit is the same as the GH 12 then the test is the same.
        • GH 6 - The circuit is two 6V filament lamps in parallel rated at 100 mA and 200 mA. If one lamp fails then the other lamp will be supplied with too much current and fail.  Therefore, turn the wheel slowly at first to see if one or both lamps illuminate.
        2. With the wheel removed from the bike and the bearings set properly;
        • Turn the shaft and notice the dynamo detent force - which feels springy sort of lumpy and is very light.  It does not matter which direction the wheel is rotated in.
        • Short the dynamo output with a wire.
        • Turn the shaft and notice the dynamo stronger magnet resistance force - which feels springy lumpy but is significant.
        If the force was different as described the magnet is magnetised and the dynamo is good or the magnet is could be weak.

        If there was no difference then;
        • If the force is week then the winding may be open circuit or the magnet is demagnetised.
        • If the force is strong then the winding may be short circuit but the magnet is good. 
        If there is doubt about the lamp and the dynamo circuits test the lamp circuit with a battery instead of the dynamo.  Of cause, you can test with a multimeter rather than traditional methods but a multimeter in its time such as an AVO would cost more than a new bike in the 1930s.  The current from a resistance meter if connected to the dynamo may cause a small high voltage spark when you disconnect it (called back-EMF). 
        The moving Iron test meter pictured right is probably 100 years old and had cotton covered wire with a small probe tip.  It works AC or DC but the scale does not say which it is calibrated in.  Notice that the body of the meter is live, I have not carried out any measurements with this meter.  It would have been much less costly than a multimeter but it was not a cheap instrument.

        The second tool rematerialising the magnet;
        This is the same process that happens with a computer hard disk.  A high pulse of magnetism is applied to the hard iron material to magnetise it.  Such a pulse will also switch a magnets polarity north and south poles. This is done with the dynamo fully maintained and assembled then briefly connecting a high current from a voltage power source to the armature.

        It turns out that there is no need for a particularly high voltage so the risk of the armature winding insulation breaking down and failing does not exist.





        AL-0030-02B S1 is closed briefly then opened to re-magnetise the dynamo.  When S1 is closed the current starts to rise in the dynamo winding represented by L1, 5.5H (measured and calculated roughly) and R1 5Ω (measured).  D1 prevents the circuit from creating a high voltage (back EMF), ringing (oscillating), arcing which will hurt you and damage the dynamo's insulation


        RED = VoltsGREEN = Amps.
        The Ground symbol shown is not earth but is a reference point for this SiMetrix simulation.  
        20A pulse shown is probably the current required to fully magnetise the dynamo (guessing based on patent detail above and the B-H curves below). The dynamos output will be a higher current than rated but well within the dynamos capability. These magnets have a wide tolerance in magnetic strength consequently the increase in the dynamo's output will vary. 
        Providing that the mu-metal can carry this amount of magnetism without saturating - which is very likely because motors and generators are usually assembled then magnetised after assembly.

        Less self-heating occurs with the dynamo is magnetised by a higher voltage. You can see that the slope does not diminish in the rate of rising and simply heat up as in the lower voltage case above. AL-0030-01C 350VDC, 0.4 Seconds to reach 20A.  The winding needs to be dry but the insulation may have deteriorated over time so applying a high voltage to the winding may cause it to fail. 

        AL-0030-03B 230VAC with rectifier 0.7 Seconds to reach 20A. The simulation diagram in the link is different 
         to the circuit diagram 230VAC - Fuse - switch - circuit breaker - bridge rectifier - dynamo. Similar to the 
        battery charger below plus a fuse, a circuit breaker but without the ammeter, capacitor or the transformer.


        Allow the small detent force (the magnetism) to pull the armature to align the poles ready for the pulse of current to re-magnetise.  You can test the magnetism by turning the armature to feel the lumpy pull of the magnets to the armature sections.  This detent force is much bigger if you short circuit the armature and doing that will confirm that the winding has continuity and is not short circuit.
          How it works is that it produces a high current pulse - standard physics stuff but I need to experiment to find out how high the current needs to be?
          The device may require a dangerously high voltage and can produce high damaging voltage if the diode were not fitted.

        It turns out that a much lower voltage should have been used and a variable power supply so that the magnetism can be steadily increased until the dynamo produces the correct current.  The magnet is used in the linear region in a similar way that sound is recorded on tape by a tape recorder.   That is the magnet is not magnetised to saturation in the same way that hard disks, permanent magnet motors and generators usually are.

        Alternatively use a car battery charger;

        The car battery charger is connected to the dynamo, the dynamo shaft can move freely so that the magnet poles align when the pulse of power (magnetism) is applied.

        Next step is as before switched on for one or two seconds then switch off.  Take care to switch off quickly so that the dynamo winding does not heat up.  Do not disconnect the dynamo whilst the power is switched on because a high voltage, called back-EMF, will be generated that will put the winding under stress unnecessarily.  See diagram below; 
        AL-0031-02B The car battery charger has an internal rectifier diode so another diode is not required.
        Connect up then switch on for 10 seconds or so then turn off.  The setting of the low or high charge 
        switch  and then adding the capacitor will progressively increase the current and therefore the 
        resulting dynamo output after re-magnetisation.
        It turns out that it takes a few seconds for the current to build up before the armature moves. 

        What happens; The armature (generator winding) of the dynamo (generator) will move and the magnet poles (field) and armature segments will align or re-align as the current and the magnetism increases.

        Video - Car battery charger used 
        to re-magnetise the dynamo.
        Ensure that the dynamo can move freely so that the poles can align.  A moving needle multimeter or these old 2 cells 3V torch with filament bulbs (2.2V 470mA pictured) does a good job of measuring the function of the dynamos.  Look at the colour of the light to gauge current.  The old capacitors are similarly rated 30V to 63V 2,000uF to 5,600uF and the larger one is older.  

        A digital multimeter does work if you keep the hub turning steadily for a longer period.  The bulb lite up white indicating that the current was 470mA as the light bulb is rated.

        It would appear that although the magnet seems weak judging by the how much mu-metal sticks to the magnet but this type of hard iron magnet was going out of fashion in the 1950s and TV manufactures were using ceramic stronger magnets which are black rather than silver.  By holding the shaft in a vice - wrapping string around the housing and pulling voltage and current measurements are difficult to make.

        With a digital multimeter, I measured up to 400mA short circuit, although the dynamo is only rated at 300mA.  The current may have risen to 480mA after re-magnetising.   Measuring the open-circuit voltage with a moving needle multimeter was a little easier at up to 12V increased to 20V after re magnetising.  Adding the capacitor to the circuit doubled the current in the dynamo winding but did not, as far as I can tell, increase the power output of the dynamo after a re-magnetising again.

        Warning this method was too imprecise to be conclusive.  But the method is correct even though the voltage was not high enough.  Adding the capacitor doubled the current to show 50% but on testing the dynamo showed no further increase in the current output.  This is good because that indicates that dynamo is fully re-magnetised.

        To properly test this procedure and voltages suggested the dynamo needs to be fully demagnetised.  I could connect the winding to the mains 230V AC this should be adequate.  But that is risky so I am not going to do that.

        Tests 1; With the dynamo clamped by the shaft with a vice and string wrapped around the hub body then pulled;

                         Open circuit V, Short circuit I, 12V 6W Lamp
        Slow;        <10Vac,               440mA,               <4V
        Fast;          20Vac,                 470mA                ~6V
        Very fast;  30Vac,                 500mA,               8-10V

        The dynamo's output is as originally expected nearly constant current regardless of speed and an open-circuit voltage proportional to the speed of rotation.

        Test 2; Reverse the polarity of the magnet
        • Connect up as above and pulse the power on/off so that the poles align.
        • Reverse the polarity of the power supply.
        • Clamp the dynamo stationary then power on/off.
        • Un-clamp the dynamo so that it can move freely then power on/off.
        • If the magnet polarity had changed the dynamo should not move but it did move to a new alignment.
        • I also tried with a 20V DC power supply unsuccessfully.
        The battery charger probably does not provide adequate power to reverse magnetise the dynamo but it has increased the magnetism of the dynamo.  The circuit may be useful.

        1. The magnet is not fully saturated and therefore a little more power could be obtained from the dynamo. 

        2.  Because the magnet could not be reversed it is also likely that a dynamo which is completely demagnetised would not remagnetise fully without a much higher current pulse?

        Test 3; Demagnetise the dynamo so that magnetising the dynamo test can be repeated.
        • Connected a 35VAC to the dynamo  - this was not adequate and the dynamo remained magnetised but the magnetism was reduced.
        • The  current output but showed the current was reduced to; 380-400mA after the demagnetising experiment.  Then re-magnetising and increased to 400-440mA subsequently.
        This test failed to demagnetise the magnet.  I am not willing to use a higher voltage.

        WARNING - The test suggests that the dynamo's current output will be higher than rated initially and remained the same after three days and is unlikely to diminish over time.  The dynamo needs to be de-magnetised then re-magnetised but at a lower amount of magnetism.  Alternatively left as it is with higher power output.

        Test 4; Replacing the winding with the magnet keeper
        Pushing the keeper in and whilst pressing the keeper into the magnet to ensure the magnet has minimal gaps and magnet path is as good as possible.




        Winding removed - the fingers of the iron are tapered - this is unusual I do not 
        know why this has been done but it would limit the magnetism progressively.
        • The keeper has been made long enough to be used on larger diameter GH8 or GH12 dynamos.
        • Test voltage peaked at 30Vac as before and the short circuit current varied between 370mA to 420mA slow to fast.
        • The tapered fingers of the coil may be to do with proving some voltage regulation mentioned in the patent.  I do not have enough equipment to test this.
        The assembly did not need cleaning but I did wipe the parts with grease on my finger.  I am advised that the gaps between the magnet poles can be cleaned with a pipe cleaner.
        Test 5 - repeat tests after at least 1 month since re-magnetising the dynamo
        Slow; Vac open >17V (analogue),  Iac 370mA (digital)
        Fast;  Vac open >25V (analogue),  Iac 390mA (digital)
        The digital multimeter, as before, gave less reliable readings.   
        I also measure the average current with the moving needle multimeter and a bridge rectifier and this gave a consistent 300mA fast or slow.  The true value; 330mA (RMS) the metre is 40 years old out of calibration and the needle did not have a long enough period of current flow to settle at a final value.

            Ipk = Iav / 0.637
            Irms = Ipk x 0.707 
            Irms = Iav x 0.707/0.637 
            330mA = 300 x 1.11  -  Warning although the analogue multimeter gives consistent results it most certainly is under reading and the current is higher.

        Using a light bulb 2.2V 470mA and 12V 6W I perceive that the dynamo power has diminished a little.  The multimeters tests suggest reduced by 5-10%.  The moving needle multimeter did not fully settle because I was not able to keep the dynamo turning long enough but it gives the most consistent results.

        Conclusion - re-magnetising and electrical;
        The magnet material has a tolerance but evidently, the magnet was not originally magnetised to its saturation but even so, still has very good retention of magnetism.  With readily available fixed voltage second-hand equipment power supplies it is only possible to re-magnetise a dynamo to give maximum output about 400mA AC in this case. 

        My guess is that there is a fixed voltage, therefore, current used to partially magnetise the magnet in order to achieve 300mA dynamo output current. It is likely that the correct voltage is found and set for each batch of magnets.

        The point about magnetising to saturation is so that the magnet would be as strong as possible but the material used has a broad tolerance.  This tolerance would have made the output power vary between batches of dynamos made. Much more power is required to magnetise the magnet to saturation but the amount of effort required to demagnetise the magnet is also much more so the retention of magnetism would be better.  It turns out that unlike tape recording the magnetism does not seem to fade but I don't know if when generating power might regenerate the magnetism slightly?

        Older style block power supplies have very loose regulation so it should be possible to wire a number in parallel in order to achieve the desired current rating and because of there loose regulation the current would be shared fairly equally.

        Pictured right; Old heavy transformer type block power supplies.  These range from 12V, 1A to 1.5A so two in parallel should be enough to re-magnetise a dynamo.  Four in parallel, in series with another four in parallel increase the amount of the dynamo is re-magnetism.   That is 12V, 2-3A or 24V 4-6A.  Ensure that all are plugged in then switched on and off together.

        Rectifier regulator and LED lighting;

        You can scavenge for rectifier diodes from an old PC power supply the low voltage side diodes are usually more efficient lower voltage drop Schottky types.  Schottky diodes have a low reverse voltage rating of 20V or higher but some newer types are rated at over 100V this means that a low reverse voltage rectifier could be destroyed by the dynamo at speed if the lamp units are disconnected.  LEDs from a car head, side and tail lights - generally if one LED fails the whole set is turned off and a dashboard warning is shown is a legal requirement in order to avoid ambiguity.  A 10,000uF 10V or bigger smoothing capacitor and Zener diode which will give low efficiency, low flicker lighting but these suggestions below are a little better;
        Dynamometer tests ( on a GH6 dynamo show, the dynamo's output reached 6V 300mA at 30KPH below this speed, that blog's LED lighting drew progressively less current.  For a 26' wheel which covers about 2M per revolution the output frequency would be 83Hz which would not produce any noticeable whereas 50Hz can is noticeable. 
        • Therefore half-wave rectifier circuit (1) and 2 but without capacitors may not notice flicker above 15KPH (41Hz).
        • The full-wave rectifier circuit (3 and 4) with the capacitors not fitted and would not noticeably flicker above 7KPH (41Hz).
        Capacitor values are estimated based on simulation for <30% current ripple in th LED at a frequency of 20Hz.  Arbitrary White LED was chosen and scaled for RED LED in the LTspice simulation AL-0037-???.
         1) 100%  current;  Total = 5.7V = (White LED 4V) + (Red LED 1.7V). 
        The LEDs will alternately illuminate with the generator's AC output.  At low speed, all LEDs turn off as the voltage transitions through 0V.  Together this may not look acceptable to oncoming traffic or pedestrians.
        2) 50% current, Voltage drop;
        • Total = 4.4V (white) = (Diode 0.4V) + (White LED 4V) and
        • Total = 2.1V (red) = (Diode 0.4V) + (Red LED 1.7V).
        Circuit 2 and 3;  If one Lamp is disconnected then the rectifiers will need to withstand at least 30V reverse voltage.  A Schottky rectifier rated at 50V or higher is required.
        3) 100% current; Total 6.5V = (Diodes 0.8V = 2 x 0.4V) + (White LED 4V) + (Red LED 1.7V). 
        The reservoir capacitors shown are much less necessary than they are in circuit 2 they can be of a lower value in circuit 3.
        4) Voltage limited;
        • Input; 5.8V = 3.9V + 1.1V + 0.6V. Surplus power returned to the wheel. 
        • Output; 5.0V = 3.9V + 1.1V + 0.6V - (2 x 0.3V).
        • Therefore the output voltage full load 4.8V = 3.9V + 1.1V + 0.6V - (2 x 0.4V)
        • No allowance for temperature has been calculated but the voltage is likely to be 4.5V to 5.5V.
        • Extra power wasted by the triac (z01 ST) <300mW from a graph in the data-sheet.  Compared to <2W for a Zener diode shunt regulator solution.
        Provides enough voltage to run a USB device but the voltage being nearer the minimum be too low for that the device to charge at a good rate at the same time not so high to exceed 5.5V maximum. 
        Simple Lighting systems suggestions (AL-0035-01C)
        The LEDs may flicker a little but I have shown various mitigation measure and I also suggest using scavenged parts.

        No allowance has been made for temperature and component tolerance (worse case design).

        DC-DC converters & LED drivers;
        A variable voltage or LED driver from 5V input evaluation boards-
        I have not evaluated any of these.
        PAM2841SR boost LED driver 2.7V to 5V in. There is an evaluation board for this IC.  Note that the input voltage must be lower than the LEDs (in series) voltage drop so that the IC can regulate the current.
        There many other manufactures and types such as PAM2803, ZXLD1321 operates 1V to 3.3V at least.
        ST buck-boost type use with circuit 4;


        By combining the voltage pre-regulator above and then using a cheaper semi-regulated function block should be cheaper than using the evaluation boards above solution.

        Picture right;  Surface mount LEDs - A Printed Circuit Board can be made with a footprint pattern like the reverse side but as if you were looking through the parts from the top.   Design the board with components on one side only.  Place very small dots of solder paste on to the pads (it should look as if you have not got enough solder paste on the pads).  Then place the LEDs and other parts on the PCB you don't need to fit all parts at the same time or be overly careful to align them properly surface tension will cause the parts to pull to align (or miss-align).  Place the circuit board on a suitably pre-heated hotplate to solder all the parts.  Using tweezers to correct any parts that go out of alignment or tombstone (stand up).  Use pliers to remove the board from the heat.  The board will go brown because it has been overheated and for too long but your circuit will function fine - heating and cooling need to be done quickly without jarring the PCB.

        No PCB need to be designed and ordered if you unsolder the parts off of an old circuit board, cut the tracks as necessary and place your desired circuit and wires this works well.   Alternatively you can buy some stripboard or Vero board and do a similar thing with that but you probably will need to reduce the power rating of some parts such as LEDs in order to prevent them from overheating due to the lack of solder pad, copper area for heat-sinking.

        Picture left - Stipboard or Veroboard can be used for prototyping of finished one-off design.  The prototype may be a mains power supply with switch-mode Lead-acid battery charging?  This type of prototyping can be good to see how a function works but usually, the function does not work so well unless it is not demanding.

        Alternative - Bicycle dynamo light and battery manager  ---  See Addendum at the bottom of the page and also see;  electronics-design-project-bicycle

        Links and references;
        Tests of modern Hub dynamo efficiency's;

        GH12 (1936-38) - Dynohub
        GH6, hub dynamo, AG and FG variable gear hub-dynamos.
        Note that the GH6 front wheel fitted type hub dynamo 
        bearing adjustment is carried out from the non-dynamo 
        side.   Unlike the AG variable gear dyno-hub.  

        Magnet and magnetic material characteristic B-H curve.  B = Magnetic force and H = Amp turns the current in the wire and the number of turns of wire if there were no losses in the magnetic circuit. 
        AlNiCo Magnet (aluminium, nickel, cobalt) material B-H curve shows the magnet can be magnetised at a lower degree of magnetism.

        At very high temperature the material will de-magnetise called the curie point.  When the material cools again the magnetism can return.  This way is not used to magnetise the magnet.  The magnetisation is usually done after assembly with the material cold with a strong pulse electromagnetic field;

        History of modern magnetic material;
        Another bicycle dynamo project I am unsure about the data and the project was not completed but there is a useful dynamometer graph for a dynohub;

        Other links;

        Pandemic cycling and bicycle selection going-forward  + Starting to ride a bicycle again.

        Raleigh Lenton sports bicycle  + General maintenance advice, technical and history.

        Appendix; Motors that will also generate power; 
        • 1970's Impex 350mA, 5V/winding (4) 48 step stepper motor.
        • 1950s Induction motor (variable reluctance) - is not magnetised but will magnetise when connected to an AC power and spinning.  The capacitor provides a phase-shifted supply and sets the motor direction.  This motor will become a generator when spun a little faster than synchronising speed and put power back into the supply.  If disconnected the motor stops generating power safely.  But if capacitors are connected across the windings and the rotor has remnant magnetism some of these motors will build up magnetism and start to generate power when spinning.
        • Permanent magnet brush motor - will produce direct current if spun.
        • 1980's Astrosyn stepper motor; 24 step, 16V, 80ohms (200mA)/winding (4) - this has a very much more powerful magnet than the 1970s Impex motor and is a more powerful motor although it is smaller.
        • Central heating timer permanent magnet motor - this is like the dynamo in construction but turned inside out.
        • Hard disk stepper motor 8 pole - this will also generate but the voltage is so low that it would have no use.
        Picture of a high number of steps, stepper motor. The shaft is mild steel and can bend easily so the coupling to the shaft must be flexible.  The construction is different from the dynamo with the two rotors are North and South poles of a central magnet so that the teeth then present alternate poles as the rotor turns.

        The motor is assembled then the magnet is magnetised by a pulse from a high voltage source.  This type of construction is used from 24 up to 500 step hybrid stepper motors.


        Appendix; Bicycle dynamo lights and battery manager;
        Microcontroller based bicycle dynamo light and battery manager with a speedometer. Design idea and exercise with STM32 microcontroller. With interface by USB cable for speedometer display on a tablet for example. 

        The dynamo will output up to 20V when the bike is ridden fast I understand.   If we assume the dynamo will deliver 300mA then the output power is 7W but we can probably count on getting at least 5W. In order to get the maximum power from the dynamo, the current taken needs to be regulated so that voltage does not drop and thereby causing the power taken to drop below maximum.
        AL-0036-03D Power diagram based on motor driver to operate at high-frequency boost switch-mode.
          The bike needs to be moving at a good speed in order for enough voltage (>8V peak) be generated to 
        start up the power supply in this design.  Most function blocks and parts are not shown and part values 
        are not correct.
        • Manage battery charging.  Therefore it is best not to remove the battery's in order to maintain the battery state of charge and capacity learnt.  USB port charging either direction and data link.
        • Tilt sensor used to reduce the power taken from the dynamo using parameters set by the cyclist such as from a tablet computer connected.