Rear brake caliper doesn't sit parallel with disk after fitting rear hub motor.

[KG-Ebike]

Hello I have been working on converting a MTB to ebike and I have ran out of ideas on how to sort out my rear brake.

As you can see in the picture the brake adapter isn't parallel with the rotor making it impossible for the pads not to rub.


There is a 2mm gap between the adapter and the rotor at the top whilst a 1mm gap at the bottom.

For the caliper to be aligned perfectly it would have to
Sit like this obviously no good as you can't fit a bolt into the hole.




I have tried placing a small washer in-between the frame and the adapter to try and straighten it out but I then run into this problem.



As you can see the caliper is at its furthest point to the left but the rotor is pressing on the left brake pads and now looking at the picture the caliper still doesn't look straight

I'm using a 3mm anti rotation washer as a spacer on the axel. If I go any smaller the caliper hits the hub.

Any ideas please?

 

[docw009]

Were the droputs spread a bit to enable the hubmotor to fit? When you do that, the chainstays don't stay parallel and that could be why the bracket is not aligned.

Instead of adding material on one hole as you did with the washer, how about grabbing a file and removing it at the other hole? I once had to take off 1-2mm along the whole bottom of one bracket, as well as cut down one of the vertical posts to get a caliper aligned on the rotor. I's a cut and try process.


These brackets are inexpensive, so if you ever want to put the bike back to no motor, it's easy to get a new bracket.

 

[KG-Ebike]

Ye I did have to slightly spread the dropouts and I also believe that is what the issue is. I will have a look at filing the adapter down. Thanks for the suggestion