Author Topic: Rear brake cable, another one, and torque arm.  (Read 757 times)

Offline philwhitelaw

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Goodness me, I cant get off this forum now! Can you enlightened souls tell me if a brake cable is more efficient if it is straight rather than curved? I would say yes. The original cable on my 61 GF has a longish curve running under the swing arm to the downward sitting brake arm. Its a 13 1/2 inches outer which is the same as replicas for sale online. In order to straighten the curve I was contemplating on making a longer torque arm in order to turn the drum clockwise a bit more. Has anyone tried this before or am I wasting my time because there would be no noticeable benefit or is there a shorter cable available somewhere?  Also the torque arm has a gap between it and the swing arm lug it bolts to so I have to pack it out with a spacer so that the backplate sits square to the drum, is this normal?  I think I have too much time on my hands at present!!! *eek*

Offline Billybream

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Re: Rear brake cable, another one, and torque arm.
« Reply #1 on: 07.04. 2020 19:46 »
A good mod is to convert to rod arrangement, you can find info on this forum, not easy, but would remove the spongey feel.
You are correct and a spacer is required between torque arm and frame lug.
Rear brake set up is a challenge, you need to pay attention to lever angles and obtain decent linings, but once set correctly is not a bad brake.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline muskrat

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Re: Rear brake cable, another one, and torque arm.
« Reply #2 on: 07.04. 2020 20:41 »
G'day Phil.
It shouldn't really matter. Look at your front cable. The spongyness is the outer cable compressing under load. So buying the best quality cable from a reputable cable manufacturer is best.
As Billy said, converting to rod is best. https://www.a7a10.net/forum/index.php?topic=1163.0
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Offline chaterlea25

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Re: Rear brake cable, another one, and torque arm.
« Reply #3 on: 07.04. 2020 21:19 »
Hi Phil,
Quote
is there a shorter cable available somewhere?

A short answer is Yes   (JJ cables)

The longer answer is that the suppliers information on fitment is mostly incorrect
The next part of the problem is that most pattern brake shoes are lined with too thin a lining
this results in the arm on the hub winding up at the wrong angle for best effeciency
then owners move the cross over lever forward to take up slack in the cable resulting in a *** poor brake

I was working on a late model A10 last week and went to correct the cable length as the inner looked too long
Anyway the ends were crimped  *sad2* so not easily moved
I had another cable, and tried that, Bingo  *smile* the length was perfect moving the cross over arm two splines to approaching 90 degrees
The result is a good usable brake
The bike has gone back to its owner so I do not have the cable length to hand now

I modified the cable on my own 61 SR some years ago to correct the lever angles resulting in a brake that will lock the wheel
I can measure the length tomorrow if you need ?

John
1961 Super Rocket
1963 RGS (ongoing)

Offline philwhitelaw

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Re: Rear brake cable, another one, and torque arm.
« Reply #4 on: 07.04. 2020 22:07 »
Thanks John and Musky. The cable length with the ball ended brake lever set to the 10 o'clock ish position might not be a problem as I have a local engineering firm that make an extended brake arm. Check them out they are called CPC Engineering from Camborne in Cornwall, Chris has a really impressive set up and makes a lot of BSA parts in stainless.

Offline muskrat

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Re: Rear brake cable, another one, and torque arm.
« Reply #5 on: 08.04. 2020 06:07 »
G'day Phil.
I did similar to my front lever. A lot better.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Offline chaterlea25

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Re: Rear brake cable, another one, and torque arm.
« Reply #6 on: 08.04. 2020 14:46 »
Hi Phil,
My modified cable measures
19 1/2 in. From the end of the ball to the clevis pin centre
The length of the outer including the
adjuster and front end fitting is  just under 14in.

John
1961 Super Rocket
1963 RGS (ongoing)

Offline philwhitelaw

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Re: Rear brake cable, another one, and torque arm.
« Reply #7 on: 08.04. 2020 15:53 »
Hi Musky,  I tried sending you a message yesterday, did you get it?

Phil.

Offline philwhitelaw

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Re: Rear brake cable, another one, and torque arm.
« Reply #8 on: 11.04. 2020 12:57 »
Thanks John.

Offline BigJim

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Re: Rear brake cable, another one, and torque arm.
« Reply #9 on: 11.04. 2020 18:13 »
Trust musky to need two levers on his bike!! At the speeds he goes it's no surprise!
 *doubt* *bright idea* *sick* *shh* *shh* *shh* *beer* *whistle*
Jamie,  Supporter of Distinguished Gentleman's Ride