Hydraulic Disc Brake Interference

[truly_bent]

Rats (and other unmentionables)!

Just tried to mount my rear MP onto a Brodie Kinetic which has hydraulic disc brakes and, wouldn't ya know, the double caliper housing interferes with the motor.

I can see that, even if the housing didn't interfere, the disk wouldn't line up properly anyway and the caliper housing would have to be shimmed out, or the disc would have to be shimmed toward the frame - not a good idea at the best of times methinks.

I'm guessing that my only option here is to replace the hydraulic brake with a mechanical cable type. Any other ideas?

[Bikemad]

If you don't want to space the disc and you can't find another hydraulic caliper that is narrow enough to fit, then switching to mechanical is another option.

Andrew managed to get this hydraulic caliper to fit with "some filing":



It's worth noting that the rear brake disc fixings are under a lot less force than the front ones, and the torsional force acting upon the disc is reduced even more when you're using regenerative braking as well.

Alan
 

[truly_bent]

Alan;

I went out and bought an Avid BB7 mechanical caliper, which gives me space between the MP and the caliper. I still need to space the disc out from the MP, but i'll do that with washers. Thanks.

Next concern is the dropout fit. As you can see from the attached pic, there isn't a whole lot of support for the axle. With a bit of judicious filing, the axle can be moved deeper into the dropouts by another 2mm or so. Does this look like sufficient support or can you recommend another option?

By the way, how do you insert a picture in the middle of a post? I've tried spacing the name of the pic between img /img pair, but the preview doesn't show it correctly

[Bikemad]

Aluminium dropouts are known to break due to the motor load and regenerative braking torque acting upon the axle, so I would strongly recommend that you use a sturdy torque arm to transmit the axle torque. There are many different types of torque arms available, or you could make one from a piece of steel plate if you have metalwork skills.

Check out this video by Doctorbass on Endless-Sphere.

Gary (GM Canada) keeps these torque arms:



Check out this post regarding posting images.

Alan
 

[truly_bent]

Gary's battery was just about to ship yesterday. I already had one of his torque arms included with that order and was able to add a second just before it went out.

Thanks for the advice.