Author Topic: Why is my front brake still useless?  (Read 3484 times)

Offline BSA_54A10

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Re: Why is my front brake still useless?
« Reply #105 on: 01.05. 2020 05:54 »

Next is incorrect radiusing of the shoes.
To work as intended the shoe must have a LARGER radius than the drum so the initial contact will be at the end only. ***
The leading end digs into the drum which locks onto the shoe and forces it back against the pivot end which can not move so the shoe flexes into the drum.
Thus the rotational energy in the drum is supplying the breaking energy , not your grip.

Do you mean like this?

A trailing shoe marked 68-5525 which is 197mm across and only touches at the extreme edges as seen in the second image, the gap is about 1.5mm. Next to it is a leading shoe which is 191mm across and has good overall contact as shown by the blue ink. Obviously not a matched pair so which size is the best fit?
Yes rather like that
The idea of the steel caps on the brake shoes is so you can shim the  pivot end of the shoe to account for wear in the drum.
just the same as the oval pivots on the Ariel type hub
The pivot end of the shoe should be as close to the drum as you can get it.
The closer the better
Bike Beesa
Trevor

Offline philwhitelaw

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Re: Why is my front brake still useless?
« Reply #106 on: 01.05. 2020 13:40 »
Thanks Trevor, getting hold of those end caps is a bugger tho. Might have to make something myself.

Online Peter in Aus

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Re: Why is my front brake still useless?
« Reply #107 on: 17.07. 2020 01:57 »
Decided to have another go at my 58 A10 full width rear cross over (near useless) brake. Ground off about 35mm of the top of the leading shoe (cam end) lining and filed the cam on the trailing side of the cam so as the leading shoe came on a bit first.
The result was a 50% increase in braking efficiency, but still not as good as it should be, but much better than it was. *problem* *good3*
Peter

This worked for a while but gradually went back to being next to useless, so start again, having brake drum skimmed and seeing if I can get some different linings. would like to get some with some nice asbestos in them *whistle*
Peter 

Busselton West Australia
49 A7 longstroke
58 A10  SA