Can't centre r...
 

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[Closed] Can't centre rear caliper over rotor

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Posts: 6
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Topic starter
 

I just fitted a new XT ice-tech rotor on the back of my hardtail with new pads, but even though the caliper is fully over to one side, the inside brake pad is always touching the rotor.

It's a 6 bolt rotor fitted to a Roval branded DT Swiss rear hub. The brakes are SLX mounted on an adapter, the frame has old-style international standard mounts.

The only thing I can think of is that the hub axle somehow shifted in the direction of the cassette, making the rotor mount off centre. Has anyone else seen anything like this?


 
Posted : 24/09/2017 12:26 pm
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I don't know those hubs - are they not captive sealed bearings ? If they are then I don't see how this is possible. I suppose you might have lost a spacer/cap from the non driveside but can't really imagine that.

Is the wheel centred in the frame? Did this wheel ever fit properly in your frame and work with that brake?

If everythign seems OK, how about spacing out the rotor with some washers, or even a proper 6 bolt spacer ?


 
Posted : 24/09/2017 12:41 pm
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[quote=scaredypants]Is the wheel centred in the frame?

^^ This, particularly if it's a QR dropout.

Also, did you reset the pistons (push them right back into the caliper) when you changed pads?


 
Posted : 24/09/2017 1:09 pm
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If it's QR, have you got the springs the right way around?


 
Posted : 24/09/2017 1:10 pm
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Topic starter
 

It's a QR dropout indeed. The hub has sealed bearings. I did push the pistons back in before I put the new pads in. I'll have another harder look at it this evening and post back if I have anything new.


 
Posted : 24/09/2017 1:14 pm
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Back in the day we used to shim the brake adapters to tune this out.


 
Posted : 25/09/2017 8:52 am
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Is the disc on the right way around?
Might cause a mis-alignment?


 
Posted : 25/09/2017 9:43 am
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Scienceofficer - Member
Back in the day we used to shim the brake adapters to tune this out.

Did that not so long ago with my Spearfish frame, just a little 0.5mm spacer on the adaptor between it and frame.


 
Posted : 25/09/2017 9:46 am
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Scienceofficer - Member

Back in the day we used to shim the brake adapters to tune this out.

I thought that was the proper approved method with IS! Otherwise you don't have any adjustment at all!


 
Posted : 25/09/2017 9:50 am
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Looking at the caliper from the rear of the bike to the front, its the right hand pad thats rubbing?
Then you just need to add some shims between the caliper and frame or mount adapter (if fitted) surely?


 
Posted : 25/09/2017 10:20 am
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I thought that was the proper approved method with IS! Otherwise you don't have any adjustment at all!

There's also the option of taking to the frame with a file.


 
Posted : 25/09/2017 10:34 am
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I took a file to the disc adaptor, not the frame, on an old Specialized as the caliper would not sit centred. It seems that despite 'standards', some hubs or slightly wonky frames just will not play ball.
In my case it is the Mavic hub/wheelset - as I needed the same filed adaptor when I changed the bike frame....


 
Posted : 25/09/2017 10:47 am

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