Arcing brake shoes

[mikeinnh]

I'm going to be using a CB77 front brake, laced to the stock 19" aluminum rim with Buchanan's spokes on my '74 TX650A Yamaha. I'm thinking about having Vintage Brake arc the shoes. Is it advisable to have this done with the rim installed and trued, or can it be properly done with the hub only? I've emailed Vintage Brake with this same question, but I thought I'd ask here as well.

 

[AgentX]

Aren't the shoes arc'd on the backing plate, separate from the wheel? What does the rim and lacing have to do with it?

 

[mikeinnh]

On the backing plate yes, but they're arced to match the id of the drum, minus about .010" - .020". I had heard, at some point in the distant past, that adding the spoke tension could actually change that measurement. This is probably Bravo Sierra, spoken by someone who didn't know what they were talking about. Besides the CB77 drum isn't exactly fragile either. I was just wondering what the accepted procedure was as I'd never had it done.

 

[jsharpphoto]

don't you mean stock 18 inch rim? CB77's had 18 in front and rear

 

[cxman]

you just need the brake drum diameter for them to match the shoes to

the brake drum size had better not change from spoke adjustment or its defective and weak

arcing the brake shoes has amazing effect on braking and should always be done if possible

way better brakes and shoe life way less pedal effort

 

[teazer]

Brake shoes should be arced on the backing plate to match the diameter of the brake drum AFTER the drum has been skimmed. CB77 hubs are not as strong or stiff as people seem to think, Yes they are better than some alternatives, but they can be pulled out of round when truing a wheel and they tend to grow when hot. On a heavy bike or if used for heavy braking, it is essential to get clean cool air in there.

 

[mikeinnh]

don't you mean stock 18 inch rim? CB77's had 18 in front and rear

I'll be using the TX650's rim. Buchanan's makes spokes for this application.

 

[jsharpphoto]

Ahh. I figured since you were using the cb77 hub, you were using the rim too

 

[mikeinnh]

Brake shoes should be arced on the backing plate to match the diameter of the brake drum AFTER the drum has been skimmed. CB77 hubs are not as strong or stiff as people seem to think, Yes they are better than some alternatives, but they can be pulled out of round when truing a wheel and they tend to grow when hot. On a heavy bike or if used for heavy braking, it is essential to get clean cool air in there.

Ventilation is certainly something I'm considering. Thanks for the input!

 

[Scruffy]

If the CB77 has anywhere near the pathetic brakes of it's SLS CL siblings... carry an anchor with you. The front SLS on my CL72 couldn't stop a Big Wheel. The rear TLS on the other hand is quite decent... Was going to run TLS on both ends, but used the spare front wheel on a closer to finished project.