Road brake shoes - what's the small screw for?
ElectronShepherd
Posts: 227
I'm in the process of putting new blocks into the brake shoes on the road bike, and I have a daft question: What's the small screw for?
See http://www.bobs-bicycles.com/images/P/S ... -Shoes.jpg for an example of what I'm talking about.
The silver hex bolt is the release for the brake block, and lets it slide in and out of the metal shoe and holds it in place. What's the black slotted-head screw for? It doesn't seem to be holding anything in place, or have any point to it at all.
See http://www.bobs-bicycles.com/images/P/S ... -Shoes.jpg for an example of what I'm talking about.
The silver hex bolt is the release for the brake block, and lets it slide in and out of the metal shoe and holds it in place. What's the black slotted-head screw for? It doesn't seem to be holding anything in place, or have any point to it at all.
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No idea. Never seen that before. There's no mention of it the the Shimano tech docs, either.
To be honest, I never understood why road bike brake shoes have those 'fins' on them at all.
Sorry, that's not much help!
Rob0 -
Just an extra safety thing. Rather than just rely on friction, it positively fixes the pad in place.
not sure about the fin things though.0 -
Guanajuato wrote:Just an extra safety thing. Rather than just rely on friction, it positively fixes the pad in place.
not sure about the fin things though.
The "fin things" are guides for putting the wheel back in.0 -
The slotted screw below the pad is made from hard plastic. If you let your blocks wear too low this makes contact with your wheel before the metal carrier and makes a hell of a noise but no damage. If the metal carrier was to contact the rim it would cause real damage very quickly.0
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I have some KCNC brake shoes which I cut the fin bit off and sanded them down to below 5grms and they work fine. They could be the lightest shoe's in the world ,,,seriously. I don't know of any lighter.
Back on topic... If you remove that screw,,, your bike will self destruct.0 -
The fins are a throwback to the old little levers (can't remember what they used to be called) that used to be fitted to brake calipers to aid pulling the caliper close to the rim with one hand whilst tightening the cable with the other.Here's some examples.
In the old days there used to only be a spring in the caliper and not also the brake lever so the caliper springs were a lot stronger to return the brake lever at the other end of the cable. The little levers gave greater leverage to aid closing the caliper when tightening up the cable.0 -
BillyMansell wrote:The fins are a throwback to the old little levers (can't remember what they used to be called) that used to be fitted to brake calipers to aid pulling the caliper close to the rim with one hand whilst tightening the cable with the other.Here's some examples.
In the old days there used to only be a spring in the caliper and not also the brake lever so the caliper springs were a lot stronger to return the brake lever at the other end of the cable. The little levers gave greater leverage to aid closing the caliper when tightening up the cable.
Which explains why they don't feature on pads designed for cantilevers.
Thanks for that. It's puzzled me for years.
Rob0 -
Sandyballs wrote:If you let your blocks wear too low this makes contact with your wheel before the metal carrier and makes a hell of a noise but no damage.
That makes sense - thanks for the explanation.0 -
ElectronShepherd wrote:Sandyballs wrote:If you let your blocks wear too low this makes contact with your wheel before the metal carrier and makes a hell of a noise but no damage.
That makes sense - thanks for the explanation.
Sorry OP but it does not make sense to me. I might be a bit dim but to me the black screw does not line up with the rim and it will never touch it. The little silver screw is the one that will make a noise.
To me your question is still unanswered.0
