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[Count Johnny]

Chaps



(While admitting that my footbrake is non standard; that my rear (half width) hub is flipped through 90 degrees; that my rear brake is ridiculously good; and pointing out that - having tried to kill the Bullet Whisperer - I re-engineered things so that the rear hub can't slip on its adjustment slot) I seem to be eating rear brake lever splines.



This can be quite exciting when you're a hundred miles from home and have to rely upon the front (half width) brake in the pouring rain. Not as exciting, though, when you're 850 miles from home and at the top of a mountain in Spain.



Soooo…has anyone else had this problem and come up with an engineering solution that doesn't include welding the lever to the rear brake cam.



Thanks in advance.

[Adrian]

I have come across this on another RE forum not long ago, and I'd be looking at possibly adapting the rear brake cam and lever off something like a BSA C15 or Starfire. The spindle is, if I remember correctly, squared off where the lever sits, and the splines are fewer but meatier. The C15 rear brake is also 6" and you might be able to use the whole brake plate. A.

[PeteF]

textDrill it and pin it??

[PeteF]

Drill it and pin it??

[Tim NZ]

Hub slip in its adjustment slot??? Do you mean the cam pivot???


That is a fundamental feature of the effective working and adjustment of the rear brake; the problem you are experiencing does not happen on the Std bike, so I'd advise that you review the engineering aspects much closer?


Most SLS braking issues are as a result varying servo action and an inadequately supported brake plate. Moving the pivot/anchor points has directly affected torsional loading, and is a radical modification to the motor vehicle...


I hope that you wont ever sell the bike in its modified form? With out engineering credentials to endorse the modifications (alteration) of your brakes, and accepted by the MOT, you could be held liable for any serious consequences that arise...




If you look at the rear brake plate on the UCE bikes (wheel flipped 180 degrees from earlier) you will notice a much stiffer brake plate. Even so, stripped (sheared) brake PIVOT anchor studs are not unheard of.

[Count Johnny]

Hi Tim



No, I'm not referring to the brake cam - I get all of that floating stuff - I'm referring to the rear brake pivot pin moving laterally in the axle plate in response to the torque produced when the brake is applied (which it doesn't, anymore, since I fixed it).



Fundamentally, I think the problem is that (thanks to Classic Brake Services) I've got a rear brake that is just too good for the splines that are cut into the standard (made from cheese) brake lever.



And thanks, Adrian and Pete. Two good ideas.

[Count Johnny]

I probably should have added that the brake plate is more than adequately supported and that I've also probably added a lot more mechanical advantage, in terms of leverage, than standard.

[Beezabryan]

What you are saying is that something is really wrong/crap as an efficient brake is causing so much damage.
Sounds like something that was not broken has been fixed until it is.

[Count Johnny]

Well, Beezabryan,



I changed from a QD hub to a HW hub for reasons of appearance, and that (amongst many other things) required different chain adjustment arrangements and changing from the existing cable operated rear brake to a more traditional 'rod' operated brake.



Pretty much, from front to back, Slo Poke is full of bits of one-off engineering and disparate parts that we've got to work in harmony with each other so - being a pragmatic sort of chap - I look upon little issues like this as a part of a development process.



An obvious potential fix would be to reduce the leverage that's available but, right now, I think it it makes sense to see if we can't better engineer the final link in the chain.

[Count Johnny]

To give you an idea of what I'm talking about:



Rear hub:






Solution to brake pivot pin slipping:






Foot pedal: