Rear brake conversion, cable -> rod

[Butch (cb)]

I've seen this conversion discussed hereabouts a few times. I'm currently running a QD set up at the back with what I take to be a full width drum. It operates via cable.

I've managed to get myself another gear change lever which I understand should have the dia and spline pattern that I need - I've yet to try it. My question here relates to the relationship of the arm length I'll use here against that of the drum actuator itself.

I want to leave the cable anchor on the brake plate as is, so to get around that I'll need a longer actuator arm such that the rod will then pass over the top of this. I'm presuming to therefore increase the length on the shift lever that I will be using such that I have the same ratio and hence the same mechanical advantage.

Does anyone have a view on whether there is any advantage (sorry) on changing that ratio, I don't really want to be fooling with a lot of trial and error - my workshop is not that well equipped.

Thoughts?

[bsa-bill]

Much good info here http://www.a7a10.net/forum/index.php/topic,1163.0.html

To go off at a slight tangent and give you something else to chew on has anyone fitted the 7 inch TLS front brake to the rear wheel, this is a thought I have had at times also Royal Enfield make a 7 inch TLS that can be got for any where between 30 to 70 pounds, bit much to buy without knowing a few dimensions, I passed one up at a car boot sale as I did not at the time know what it was.
Let us know your progress

[Brian]

I've just done this conversion myself although as I dont have an engine in the bike at the moment I havent tried it yet.

The spline on the gear lever is the same. I made that part up out of an original arm as that was what I had. I made it the same length so no change to the leverage there.

Having a look I think you could use a gear lever turned around. You would need to shorten it and weld a tab for the rod to attatch to on the end.

I made the lever for the rear drum 1/2" longer. The one thing I did do was to make the angle of both levers so they sat at about 11 o'clock, they are at about 12 o'clock with the brake hard on. I also fitted a longer torque arm so the pivot point on the rear drum is slightly higher than the axle. I am hoping all this will give me slightly better geometry. Since I took these pics I have turned the torque arm into a "dogbone" and tidied it all up so it looks a bit more original. I made it all out of stainless.

The pedal definitely feels better, it goes a lot harder when the brakes are on, not so spongy. As soon as I get it going again I will know if it was worth doing.

[trevinoz]

An easier way to convert is to source the lever from an A65 rod brake Star, saves cutting up a gear lever.

Trev.

[NickSR]

Hi  Cyclobutch

If you would like to PM me your Email address I will send yoy a step by step guide

on the conversion that I completed.

Then you can choose which option.

Regards
Nick

[tedbill1]

Hi Nick

New to the forum. Most interested in reading rear brake conversion cable to rod. I had a BSA A10 Golden Flash  for my Birthday in
Jan and longing to do this conversion.
My e-mail is jeb894@hotmail.co.uk if you could message me that would be great.

Cheers

Tedbill1