DISK BRAKE: Disc rotor rubs caliper socket on frame

Tak0

Hi all!

I'm not just new to this forum, but also new to disc brakes. :roll: Hope you guys can help!

Right now, I am assembling my cross-bike and when inserting the wheels, It was very clear I am not going to be able to go anywhere, as the rotor is touching the caliper socket on the frame. So the clearance to the chain stay is okay. Here's a pic!



Is it a problem with the frame, is the rotor too much outwards, or is there something wrong with the hub?

Thanks for your help!

Tak0

Here's some more pics, just for clarity.

bendertherobot

I'm not absolutely clear as to which bit is touching which bit.

Is the top edge of the disc rubbing against the inside of the caliper? In which case you may have the wrong size discs, or need to get an adapter because of the disc size or may be able to stick some washers in somewhere to increase that last few mm of clearance.

bendertherobot

But, if you mean that the left hand part of the disc (last photo) is rubbing the part next to it, loosen up the bolts, grab the brakes, tighten the bolts and they should then centre.

What's the bike?

Tak0

bendertherobot wrote:

I'm not absolutely clear as to which bit is touching which bit.

Is the top edge of the disc rubbing against the inside of the caliper? In which case you may have the wrong size discs, or need to get an adapter because of the disc size or may be able to stick some washers in somewhere to increase that last few mm of clearance.

Hi Bender, thanks for replying. I've tried clarifying where it rubs with some awesome Paint-skills.
As you can see, the rotor rubs the socket of the brake caliper. Adjusting the caliper is therefore useless.

The bike is a China-frame.

ryan_w-2

Can you just move the caliper out.

It looks like the disc is bent over towards to caliper?

arthur_scrimshaw

It looks like the 'stack' distance from the wheel axle in the dropout isn't enough to position the disc in the centre of the caliper. The disc is rubbing on the head of the allen bolt that retains the caliper so moving the caliper won't solve the problem. It's either an issue with the frame or the wheel. The only quick solution would be to fit a thin (1mm or so) washer onto the wheel axle so this has the effect of spreading the dropouts slightly and moving the caliper outboard.

Tak0

Arthur Scrimshaw wrote:

It looks like the 'stack' distance from the wheel axle in the dropout isn't enough to position the disc in the centre of the caliper. The disc is rubbing on the head of the allen bolt that retains the caliper so moving the caliper won't solve the problem. It's either an issue with the frame or the wheel. The only quick solution would be to fit a thin (1mm or so) washer onto the wheel axle so this has the effect of spreading the dropouts slightly and moving the caliper outboard.

I've already confirmed that the wheel should be a perfect fit - on other disc brake-bikes it sits just fine. So it probably really is a frame-issue. So just stick a 12mm washer between the frame and the hub to spread the dropouts? Is this okay to do to a carbon frame? Are those washers available for this purpose or where would I get a washer like that? :oops:

arthur_scrimshaw

I'd suggest talking to your LBS, they may have experience of this problem and have the washers (or another solution) you need to solve it. It's not ideal I agree but not the end of the world either.
Just to clarify- looking at it the washer/spacer needs to be only 1 or 2mm thick and fitted to the non drive side of the axle against the drop out.

Tak0

Arthur Scrimshaw wrote:

I'd suggest talking to your LBS, they may have experience of this problem and have the washers (or another solution) you need to solve it. It's not ideal I agree but not the end of the world either.
Just to clarify- looking at it the washer/spacer needs to be only 1 or 2mm thick and fitted to the non drive side of the axle against the drop out.

Again went with your advice. My LBS told me they had seen it once before with a batch of Cube cyclocross frames. They all had to be replaced since it was a manufacturing error. I wrote an e-mail to the supplier. Now hope for some sort of guarantee. In the meantime, I'll try the washer-thing. I'm gonna need the right size tho.

bendertherobot

Yeah, a 1-2mm washer should sort that but I'd be looking at a replacement.

sungod

are the dropouts the same spacing as the hub, or you you need to spread them to fit the wheel, or alternatively is the wheel 'loose' between them and they get pulled in by the qr?

although the current norm is 135mm spacing for disc brake road bikes there have been others

Tak0

sungod wrote:

are the dropouts the same spacing as the hub, or you you need to spread them to fit the wheel, or alternatively is the wheel 'loose' between them and they get pulled in by the qr?

although the current norm is 135mm spacing for disc brake road bikes there have been others

The wheel fits like a glove in the drop-outs. It's a 12x142mm system. The problem really is the caliper mount which touches the rotor disc.

mikecassie

Hi, now as they say there is never a silly question just a silly answer... But is the disc mounted onto the splines the correct way round? The splined spigot has the disc mounted offset to the centerline, if the disc is taken off and mounted with what is currently the inner braking surface on the outboard side would that allow enough clearance for the wheel to rotate? Maybe it won't work but could be worth a go as a trial.
Hope a repair is effected soon.

Tak0

mikecassie wrote:

Hi, now as they say there is never a silly question just a silly answer... But is the disc mounted onto the splines the correct way round? The splined spigot has the disc mounted offset to the centerline, if the disc is taken off and mounted with what is currently the inner braking surface on the outboard side would that allow enough clearance for the wheel to rotate? Maybe it won't work but could be worth a go as a trial.
Hope a repair is effected soon.

I actually have tried this! It does allow enough clearance to the frame, but then positioning the caliper correctly becomes impossible - the rotor then is too much on the inside.

Plus anyways, I'm not sure how it would affect braking performace if the rotor is mounted the other way around. The rotor does have a rotation-direction. Maybe the aluminum spider wouldn't be able to cope with braking-forces..?

mikecassie

At least great minds think alike. It's weird that the frame is that far out of its designed dimensions.
What brand of bike is it? Maybe that'd help others come up with a solution for you.

bbrap

Is it possible to mount the actual disc on to the other side of the spider (on the inside rather than outside), the pics appear to show that the ends of the spider have machined (cast) flats on both sides? Although looking at the thickness of them it may result in the same situation as when you reversed the whole thing.

Rightarmbad

Looks like you have a 12 x 135 hub in there.

homers_double

Daft point but isn't the rotor in the wrong way?

Assuming thise are ice tech rotors the plastic thingy should be on the outside... Mine are anyway.