Spotlight on brakes


Stock brake effectiveness

In the early years, CLB brakes were fitted until supply dried out. From around 1996 to March 2000, the Brompton came with Saccon City 2 brakes. Since then, a brake is custom made for Brompton and can be retrofitted to older models.

How to improve brake power?

Brake blocks

My '96 Brompton Owner's Manual suggests Saccon PT 205 brake blocks. My '96 models came with Saccon 176 A brake blocks. '98 models come with Saccon 400 blocks.
According to many, the early blocks are or become too abbrasive and could cause rim failure (Spotlight on wheels (rims, spokes and hubs) - Rims worn out), unless regularly cleaned. This probably depends on local road condition: dirty, muddy, wet cycle paths.

Alternative brake blocks

Brake cables

Break not brake (old models)

Quite a number of reports on cables breaking at the pear-shaped nipple. This problem is solved in the Mark 3 Bromptons and brake upgrade kit introduced in March 2000. The new brakes have barrel type nipples.

On these old Bromptons, you may want to replace the handles to upgrade to barrel nipples.

Replacing the brake cable (old models)

Andrew Brooks, Oct 1997:
[...] spent an incredibly frustrating hour poking the brake cable ends up into the levers trying to get them to locate into the brass swivelling slotted bit inside. It's just impossible. Both times I managed it but only when for no apparent reason it just sort of clicked in to place. And only after me having been right on the brink of trampling the whole bloody machine into flatness. There MUST be some technique to it. It just can't be that difficult.

Replacing brake cables (new models)

Peter Amey, Dec 2004:
There has been a small ripple of messages on uk.rec.cycling about brake cable inners for the B. Following applies to dual pull calipers as currently fitted (or in my case as upgraded).
Someone asked about the length of the barrel on the cable end that fits the brake lever - he had bought some that were shorter than the originals. So had I and it bothered me. FWIW, I have checked with the Brompton factory and they confirmed that the barrel should be long enough to engage in the side plates of the yoke attached to the brake lever. Typical cables brought from bike shops have shorter barrels that slip down between the side plates and put the pulling load into the piece of metal that bridges them; loads that this piece of metal is not designed to take.
Worth bearing in mind if you are buying replacement inner cables.

Alternative brake handles

Alternative brakes

John Blackburn, May 1999:
What I would like somebody to explain is why some types of cable-operated brakes are claimed to be better than others. There are only three things to consider:
  1. The mechanical advantage. The term is used here in its engineering sense - the ratio of the movement at the brake lever to the movement at the block. For example, if the lever is moved 20mm and the block moves 5mm, the ratio is 4, which means that the block is pressed against the rim with 4 times the force that the hand exerts. This is a useful improvement.
  2. "Stiction" - general friction and stickiness in the cables, pivots
  3. The accuracy with which the brake can be adjusted. For example, if the blocks could be reliably located 1mm from the rim, then a mechanical advantage of 20 could be used (a 20mm pull at the lever would move the block into contact). This is complicated by the fact that the block is compressible.
So, instead of merely asserting that one type of brake is better than another, I would like to know WHY it is better.

Better calipers?

Stein Somers, Mar 1999:
It has been claimed that the Alesa caliper that used to be fitted to Bromptons was better than the current Saccon. I wonder how? The mechanism and leverage is identical. It's not that the caliper legs were freewheeling on ball bearings and are stuck with glue now. Isn't the cable much more of an issue?

Dual-pivot brakes

Fitting the Brompton dual pivot brake upgrade


Magura hydraulic rim brakes

Joerg Scheiner, Oct 1998:
[...] my local dealer told me the Magura oil tubes are not designed for daily bending that happens when folding the Brompton and thus will break and leak very early. Is this true?

Coaster brake

O'Reilly, Peter, Mar 1999:
Coaster brakes being the ones whereby you apply pressure to the pedals in reverse to brake and are commonly used for single geared bikes. I have one on a 3 speed (Shimano hub) tandem bike and it brakes reasonably well to me. Rarely do I use the front brake lever for the drum equipped brake.

Hub brake

As for hub dynamo's (Spotlight on lights - Hub dynamo (BromSON)), the front fork measures only 70mm compared to the standard 100mm or more. Standard hub brakes won't fit. Sturmey Archer does mention 70mm hub brakes, but they refer to the diameter!

Changing brake cable routing

The Brompton brake cables enter the caliper upside down. This makes the cable longer and there's concern this allows water to penetrate into the outer cable. Some candidate replacement brakes don't allow the cable to be routed this way. So why wouldn't you change the routing back to normal? And why and how would you change it?

A little modification I made to keep water out of the brake cables

Erwin de Vries, Jun 2000:
When servicing my B. I noticed some rust on the inner front brake cable, in the bend where any water that gets into the outer cable will collect. This can happen easily, as has been pointed out before, because of the upside-down arrangement of the brake cables.
At my local bike shop I found small plastic and rubber thingies made to keep water and dirt out of the brake cables on mountain bikes. As you know on many of these bikes bits of cable with and without outers are interspersed, so there are lots of places where water can get inside the outer cable.
This device consists of a tubular bit of plastic that fits over the end of the outer cable, and then narrows to a diameter slightly larger than the inner cable. The inner cable runs through a narrow gap in a rubber bit, which fits, but freely moves, over the narrow end of the plastic bit, thus keeping the water out.
Through my lack of knowledge of bike-tech English, this might be somewhat hard to understand, but any decent bike shop that sells mountain bikes will sell this item, and once you see them, it is immediately obvious how they are to be installed (if not, I could be persuaded to take a picture and send that to those interested).

Getting the brake clearance equal

Chris Newport, May 1999:
Invariably I find after adjusting a caliper and then applying the brake that the clearance on each side is unequal.
Is there a way to align and then fix the return spring so it applies equal force to both sides (and stays that way)?

Do the 'toe in'