brake calliper rubs on hub motor

[Dumsterdave]

I just got a 1000w rear hub motor and tried to put my disc brakes on it, but there is simply not enough space between the rotor and the hub for my calliper to fit. The wheel is able to rotate by hand, but it definitely cant stay like this. I currently have 160mm rotors and cannot fit anything larger on the rear wheel. What can i do? I have avid juicy 7s... is it possible to file the back of the brake calliper? im not sure how thick the casings are and i dont want liquid pooring out if i fille too much

 

[Chalo]

Get disc calipers that are narrower on the back side of the rotor, or use rim brakes.

You can add spacers under the rotor to buy a little more room, but that can make caliper setup more difficult.

 

[sonnetg]

You can also try shaving of a few mm off the caliper bracket. I am not sure if there are mech brakes slimmer than the juicy 7, but you could try shopping around. I ran into similar issue with BB7, and switched to V-brakes.

 

[Dumsterdave]

does anyone know of any thin brake callipers? maybe ones that dont cost an arm and a leg

 

[efMX Trials Electric Freeride]

what is limiting from using a larger diameter brake rotor?? such as 8" or 9" rotor?
you could space the caliper up with washers for the larger rotor.. or is the frame in the way??
what bike is this on?? any pics??

I just got a 1000w rear hub motor and tried to put my disc brakes on it, but there is simply not enough space between the rotor and the hub for my calliper to fit. The wheel is able to rotate by hand, but it definitely cant stay like this. I currently have 160mm rotors and cannot fit anything larger on the rear wheel. What can i do? I have avid juicy 7s... is it possible to file the back of the brake calliper? im not sure how thick the casings are and i dont want liquid pooring out if i fille too much

 

[Dumsterdave]

the frame is the problem. I will post pics in the morning

 

[Dumsterdave]

I decided to head downstairs and take a few more photos

 

[Chalo]

Does your bike not have studs for V-brakes?

I just mounted some new shorty linear pull brakes on one of my bikes, to clear up interference for a new rear rack. (I used self energizing cantilever brakes before.) The new brakes are ridiculously powerful, nicely responsive, easy to deal with, and of course they stay out of the way of other things.

 

[Gregor]

It looks like you only need about 3mm more of clearance, so if you can spread your dropouts another 3mm there should be no problem. Just put a 3mm washer between the hub axle and the dropout and add 3mm spacers between the hub and the disc.

 

[teklektik]

Did this exact same thing today on a new install.
Just took a few bits that I always add to an order and throw on the shelf - since I've already anted up for the shipping anyhow...

Axle spacers...
Spacewash3, Spacerwash5

Disk spacer...
DiskSpacer
(Recycle: Use an angle grinder to cut the center from an old brake disk)

Similar parts available elsewhere - EM3EV, etc.


Measure and see exactly how much extra clearance you need with your existing caliper so you can see what spacers (if any) will work. You may be stuck getting a new caliper, but yours looks like a couple of mm may do the trick. The axle spacer is there to recoup the frame clearance you lose with the disk spacer.

You can also file the mounting face of the caliper adapter to get a little more adjustment room - looks like you're at one extreme already with little if any adjustment remaining. The Avid CPS washer thingies will take care of any misalignment you introduce from filing instead of machining the adapter. Stroke the whole length of the adapter on the file as you are finishing up to get both legs with an in-line flat face - it's okay if the faces aren't quite square with the adapter (the CPS thing) as long as they are flat and lined up together to mate with the frame.

EDIT - Looks like Gregor slipped a post in while I was typing - so - "Ya - what he said"

 

[Gregor]

Ya, but your post has pictures and added red details...NIIIICE

 

[Chalo]

It looks like you only need about 3mm more of clearance, so if you can spread your dropouts another 3mm there should be no problem. Just put a 3mm washer between the hub axle and the dropout and add 3mm spacers between the hub and the disc.

AND, it wouldn't hurt to dish the wheel over to center, so the bike tracks straight.

 

[d8veh]

I've had that loads of times. I use a bigger disc and put a spacer on the axle to bring the frame clear. Don't be frightened to open your frame a bit if you have to, though probably you won't have to because it'll spring far enough. I've stretched many for wide motors. It's no problem.

Installing a spacer on the brake side and stretching the frame a bit is particularly useful for geared hub-motors because it brings the rim central in the frame without having to build an off-set (dish) into the wheel.

Don't try and grind the caliper. You always need to grind it more than you think, so you end up with a ruined caliper that still touches the motor.

 

[Dumsterdave]

Thanks guys!! I think ill head out now and look for some spacers and see what happens.

 

[Tamaranchorider]

Hey dumsterdave, I had the same problem with a Hallomotor 1000 watt front hub trying to fit an Avid BB7. I went with this item; http://www.ebay.com/itm/MTB-Mountain-Bicycle-bike-Mechanical-Disc-Brake-Front-Rear-160mm-G3-Rotors-/121669130174?var=&hash=item1c540b97be:m:mkOQ1OsMe3ku3VF40m3nruw

This brake has no adjusting dial on the inboard side of the caliper to give enough room, about 4mm of space. Works OK, not as strong as the Avid and a bit finicky on the set up. I had to use a business card inserted on the inboard side of the pads to get enough throw with the pads without rubbing. Also I did have to use spacers with the rotor too. For $25 a pair they're quite cheap but I have about 700 miles on them now and no issues.

 

[Dumsterdave]

I just threw on three 1mm washers between the hub and rotor and another 3mm washer between the rotor and dropout and everything fit perfect!
before this i was thinking i was probably going to have to convert to v-brakes I think i may be able to remove 1 of the washers though. Ill try that when i get back home

Thanks people!

 

[MadRhino]

Magura Gustav will fit as is, or else use a 225mm rotor and almost any brake will fit.

 

[KINNINVIEKID]

I had the same problem with a Dillenger 1000W front motor and the thinnest caliper I could find was a Clarke Exo Skeletal which fitted in perfectly.
Just as wel as you cant spread suspension forks very far

 

[eAdrian]

I have tried to shave off caliper 1 mm , but it did not sustain the internal pressure and broke.

For the Clarke Exo Skeleta; will this fit on 15.3 mm clearance between motor and the disk?