Braking news…

BrakesOptUp until the arrival of mountain bikes in the early 1980s, the rim brakes available were utterly useless for cross-country riding. The only alternative was drum brakes, but these were not available, except by salvaging them from rubbish dumps and ditches.

Repeated enquiries at my local cycle store suggested they were no longer manufactured. I had no reason not to believe them, nevertheless my antenna were constantly tuned to the possibility that, somewhere, somehow, my dream may come true. Then, one day in the early 70s, in that same cycle store, the Sturmey Archer representative was visiting. Having mislaid his UK catalogue, he had open on the counter an export catalogue instead. I took a sneak peek and could hardly believe my eyes. There they were, drum brakes aplenty! I had to kick-up quite a fuss before they’d allow me to order a set. Unfortunately, these proved slightly less useless than rim brakes, but enough of an improvement for me to know I was on the right track.

Towards the end of the 70s I discovered Leleu drum brakes in a cycle shop in The Old Kent Road, London. These were superb brakes, even if the engineering was pretty crappy, because they incorporated a unique feature which overcame the basic problem of drum brakes: a floating cam which compensated for brake-lining wear differential. The hubs were not marked with a manufacturer’s name, but I eventually tracked them down in Lyons, France, and secured a goodly batch. Unfortunately, the company disappeared in the mid-1980s, along with it went the source of the only drum brake that ever worked satisfactorily. Without them, I couldn’t make any developmental progress.

In the mid 1990s, Shimano brought out their Roller Brake; it has been much improved over the years and now provides better braking than even the legendary Leleu.

This is how they work: in the centre is a ramped disc surrounded by six roller bearings, which are in turn surrounded by three brake shoes, and around the outside is the braking surface.

RollerBrakeWorks

When you pull on your brake lever, your brake cable turns the ramped disc, pushing the roller bearings outwards, which, in turn, press the brake shoes against the braking surface. All parts are metal and function with a liberal dose of grease, therefore completely unaffected by, well, anything, really.

On the AventuraTT prototype, these have been working superbly for the past six years without any maintenance, adjustment or spare parts, except for that occasional squirt of grease, which takes about two minutes to administer.


Posted by ajantom

The roller brakes give excellent modulation, and work perfectly even after total immersion in water and mud.


The Landseer is fitted with the latest version of these gentle stoppers, known as Shimano IM-80, having a braking surface 80mm in diameter, a significant improvement on the smaller versions. With non-standard quick-release anchor bolts, combined with ‘RingNutz’ wheel nuts, the Landseer’s wheels can be removed without any specific tool.

FrontBrakeOptRearBrakeOpt

Imagine you are carefully negotiating down a steep, slippery off-camber slope with a sharp turn at the bottom; you do not want your wheel to lock the moment you pull the brake lever, causing your wheel to slither, reducing what little control you have. A tricky manoeuvre like this is much easier to manage if you can ‘feather’ your brakes and allow your wheels to rotate in contact with the terrain.

Roller brakes do just this with their ‘soft feel’, usually mistaken by experts for lack of power.

AvidSD7opt

When you set these brakes up with the specified Avid SD7 brake levers, adjusted to pull the minimum length of cable (that’s the little red gizmo in the photo above) and so that your brake lever is nearly touching the handlebar before the wheel actually locks, you ride with the ultimate word in sensitive modulated braking.

Ah, sensitive modulated braking, music to my ears.

Click here to go to the beginning of the whole story.

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About gmacleland

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One Response to Braking news…

  1. Pingback: Wheelbase… | Cleland > L A N D S E E R

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