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Cyclemotor Brakes

Brian Smith

Much information has been written in past issues on this subject.  Perhaps I can add a little together with a bit of historical background.

In the early 1940s, as a lad of about ten years of age, after messing about with my first cycle, I very nearly met my maker!  Living in Kendal, Cumbria, a town of very steep hills, I sped down one of them and my brakes failed.  A man leading a horse saw my predicament and put his horse across the main road, part way down an even steeper hill.  I had to choose between hitting the horse or a stone wall.  Instant decision, and perhaps humanity, won, and I chose the wall.  This wall belonged to the local hospital.  Patched up, bloodied and scarred, I returned home.  What had I done?  Well - put my brake blocks in the wrong way round.  At that time they were only clenched at one end.

The story now moves on to the early 70s when, as an engineer employed by Dunlop and working in the research department, I was given a new project.  Dunlop had bought a small company called Fibrax - yes, the same name you see on bicycle blocks today.  Legislation had just been introduced concerning cycle brake blocks.  Amongst the requirements was one that all block holders should be clenched at both ends.  Justice at last!  Other clauses gave criteria for the performance of the blocks.  In order to ascertain whether these requirements could be met, we constructed a test rig in our work's laboratory.  This was a cycle wheel with calliper brakes (Endrick) driven with an electric motor and incorporating a flywheel to simulate mass.  The brake was applied with an air cylinder, so various forces could be used.  The rim could be sprayed with water for wet conditions.

During construction we were visited by the Work's nurse who was of a curious turn of mind, especially so when confronted with a special cycle wheel.  We told her that it was a new Keep Fit machine and that the factory personnel would have to come up to the laboratory at regular intervals in order to monitor their fitness.  She believed us and kept up regular visits to check progress!

Testing proceeded via an electric motor, as Keep Fit fanatics kept their distance.  What did this prove?  Well, cycle brake blocks are made of rubber - a very cheap and filled mix, by my recollection - rims are thin chromed steel.  In the dry: excellent brakes, in the wet: disastrous.  It is well known that if you want to cut a rubber sheet, friction is lowered if you wet the knife.  A disc brake uses friction material for the pads and they are so arranged that they just kiss the disc to keep the surface dry, even when not applied.  This is impractical with a bicycle.

What can you do?  Stay at home when it rains?  In most cases this option is probably the saving grace for cycle brakes - they really are fine weather machines these days.  A number of minor helpful features were found but they certainly do not bring brakes on bicycles up to emergency stop requirements.

The best is a back pedal brake.  Metal to metal contact combined with a roller free wheel.  Japanese makes are currently available, but do count the spoke holes.  Lots are for 28 spoke 16" wheels.  Also watch your reflex time in braking.  It is not as natural a reaction as pulling a lever.

Second best: callipers squeezing the rim edge (Endrick, not pull-up Westwood).  It helps if the brakes are made more rigid by restraining their motion around the wheel with a bracket around the forks - some have this as standard.  In wet weather in traffic hold your front brake slightly applied to keep the rim dry and slightly warm.

Hub brakes: these are now rare and for most practical purposes worse than calliper unless you never oil your bearings.  There is no oil seal between cone bearing and brake lining.  They are consistent wet or dry.  Normally they are consistently poor!  Worst of all is the hub brake alongside a Sturmey-Archer 3-speed.  Autocycles use sealed hub bearings incorporating oil seals to prevent contamination.

Pull up Westwood on underside of rim: rod brakes which many cyclemotor enthusiasts favour, as being in keeping with the age of their motors.  Well, cable operated Endrick rims were in vogue by the '50s, the age of the cyclemotor and really they are much superior brakes, particularly the rear.

If it is wet and you are in a rally or any other event take great care.  Incidentally, I have recently motorised a Bickerton with 14" front wheel and 16" rear.  The brakes in the wet are absolutely useless - but more on this motorization later.

First published - October 1988
Added to archive - 30 April 1999

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