[Closed] rotor contact with caliper mount

I had this on an older Specialized. Yes frame was straight - just welded badly.

I tried three different mounts. I ended up filing the adaptor down (a lot).

Use a facing tool to face the IS mount?

Is the wheels correctly position in the drop-out, drop-outs distorted or even the back end of the frame bent? Has the frame taken a big hit - distorting the drop-outs or rear end? Is the spacing of the rim between the chainstays behind the BB even both sides? It might just simply be a distorted brake mount.

facing tool eh, be cheaper to buy a new frame!

i could file down the IS mount rather than the adaptor..?

I would file the adaptor rather than (threaded) frame area.

its been like this since new, its only beacuse ive been riding this bike a bit more often lately that its getting on my nerves! it does not seem to cause any drag, just makes noises!

mahalo - Member
its been like this since new

It is not feasible to file the (threaded) adapter at an angle, as this would mean the bolts will be crooked as well, requiring you to enlarge/ovalize the holes in the IS mount on the frame.

The only reasonable fix would be to file the adapter evenly, so as to bring it a couple of mm outwards; the alignment issue should be fixable by mounting the caliper on the adapter at a slight angle.

I'd start by making sure the dropouts were free of paint. It doesn't take much to set the axle squint. Is the tyre/frame clearance equal at both sides of the chainstays?

otsdr - they mean file the face that is in contact with the rotor. Wouldn't effect the bolts at all.

You are right, that would be much easier than filing the adapter square :).

I would file the adaptor rather than (threaded) frame area.

The frame mount isn't threaded.

If you don't want to file anything, you can add a washer / spacer between the end of the hub and the frame, by the sounds of it 1-2mm should be enough, or try a different brake mount, some of the hope ones have more clearance

It is not feasible to file the (threaded) adapter at an angle, as this would mean the bolts will be crooked as well,

Get the frame faced and a bit of fresh paint as a permanent and "correct" fix.

File a bit off the mount (and paint) as a quick, easy fix, but the mount will (probably) have to stay with the frame from now on.........

I'd do the latter. As i'm not a serial brake swapper.

The frame mount isn't threaded.

I just filed the adaptor - both sides/mount areas - as it seemed cheaper if I c*cked that up...

I have had this and the problem was the excessive thickness of the paint on the IS tabs on the frame. Sanding that offcured it.

out of interest, what is the nut for on the drive side of the axle?

As above, get it faced. I had the LBS fit some brakes to my Bfe; needed facing to fit.

Tightest brake alignment ever though.

If you've owned the frame since new you could just send it back?

Looking at the picture something appears strange...

IS mount will be machined after heat treatment of frame. On the side of the "wheel". Plus the thru holes will be drilled.

not sure if it's the picture / illusion or if it's real:

the whole mount looks "twisted" to me.
IS side close to the hub: like it's twisted "out of plane".

Fix, from above, DezB-bloke:

they mean file the face that is in contact with the rotor. Wouldn't effect the bolts at all.

its been like this since new,

Were all the components new when "new"? Does the hub have the correct spacer?

Hub axle isn't broken is it?

I cba sending it back, plus there are no more TransAM's to replace it with and i really love the bike.

the picture is not an illusion 😀

the components are most definitely not new however, the wheel has had extensive hammer, although the rotor came off another bike after only 3 or 4 rides. dont think the axle is broken, there is no play in the wheel, but i have no idea what hub spacers are in there...

all good ideas to investigate tho thanks.

As above have said - check for excess paint on the inside of the IS mount and, if you’re going to file the adaptor, then do it on the outside, so that you bring the mount back more parallel to the disc.

well i went and bought a big dock-off file ready for a weekend fettling but all was made perfectly well in an instant when i slotted a little washer between the axle and the dropout!! top tip, many thanks balirc70.

that's a 135 hub in a 142 dropout

both 100% 142mm

Put a ruler up against the side of the rotor.. Hamfisted adjustment can make them go conical sometimes. That won't be the main thing, but might not be helping.

That's some seriously squiffy welding though. I'd definitely take it somewhere with an IS facing tool but I'd be wary of removing too much from the front hole. There's not a huge amount of metal there. Normally you'd face them both to the same depth, but I'd remove just enough from the front to clear the adapter, and just enough from the rear to flatten the hole, and then put shims in between the rear mount and adapter.

No-one seems to have said this, so, in the photo, it looks to me like you have a shim between the brake adapter and the frame at the top bolt (left in photo), and not at the bottom.
that would explain it, if it's true, but i might be imagining it...

The washer is on the outside of the IS mount, probably to avoid having to shorten the bolt.

Is it worth trying an adapter from a different manufacturer? I think the Hope adapters might be a little thinner