hey guys i just installed a new set of avid elixer 5's onto my bike and the rear one is rubbing really badly (as in when i try to spin it it just wont spin at all without a bit of pressure behind it), its rubbing on the left facing from the back, its also rubbing the mount (already badly scratched from it), im at my wits end with it as ive tried realigning it countless times by loosening the cps bolts (the ones facing upwards correct?) and holding the brake firmly while tightening the bolts again,
any ideas lads?
"Re-aligning a (non-IS) caliper after refitting a wheel can be done using the loosen bolts/pull lever/tighten bolts method (LPT), but only if the caliper was correctly aligned beforehand. I'll explain why:
If the caliper is aligned by the LPT method, it assumes that both (or all) pistons are moving equally; however, it's not unusual for a new brake to have one piston moving at a different speed to the other until the seals soften/settle a little. The result of the LPT method when one piston moves less than another, or even not at all, is that the rotor end up running uncentered through the caliper, usually closer to one pad than the other, or even with only one piston doing the braking - if the other hasn't actually extended at all. If equal piston extension is not achieved in the first place, brake squeal; lack of power; and reduced modulation will be the result. The brake pads will also tend to wear at a different rate, as one will be touching the rotor before the other when the brake is applied; thus future caliper alignment will always be affected.
For optimum brake performance, both pads should touch the rotor at the same time, and both/all pistons shoudl be moving at an equal speed.
Initial caliper set-up should, in my opinion, always be done visually, or even with the aid of feeler gauges (thin metal strips of a specific thickness). With the pads removed and both/all pistons pushed back flush with the caliper, the caliper should be positioned over the rotor so that the rotor runs perfectly through the center of the slot. This will place the rotor an equal distance from the piston(s) on each side of the caliper. A few minutes taken to ensure perfect centering will greatly reduce the chances of brake issues in the future. Thinking ahead: it's also a good idea to remove the chain when setting a rear caliper as the sound of the freehub can cover the sound of the rotor catching/rubbing the pads.
With the caliper and rotor aligned properly, it's time to align the pistons/pads. The pads can be refitted and the lever pulled to bring the pistons out into operation. Two or three gentle pulls should be enough to get the pads pushed firmly against the rotor. Once you feel that the pads have fully extended, take a look at the caliper as you pull the lever. Do both pads look to be moving the same amount? Does the rotor appear to flex when the pads grab it?
Lift the wheel and spin, listening for catching/rubbing. Remember that the caliper has been perfectly aligned over the rotor, so any noise is a result of one piston moving at a different rate to the other, thus bringing one pad into contact first. The nature of the piston seals means that - if the difference is great enough - one pad will be left further out than the other when the pistons retract.
To ensure equal pad movement, the rotor can be pushed/pulled (using both hands; clean 'em first, though!) against the side which is moving quickest, while somebody else pulls the lever for you to extend the slow-moving piston until it matches the other. It's trial and error, to a extent, and might take a few minutes to balance them out.
The result of all this should be a brake which has the rotor running bang-on through the center of two pads that move at the same speed and contact the rotor at the same time as on another. An untrue rotor (zing....zing...zing...) can be gently bent using a rotor truing tool (Park, Morning Star) or an adjustable wrench.
Now that the pistons move equally, should the wheel/rotor be refitted in a slightly different position, the LPT method can be used. However, I prefer to just lift the wheel, spin it and move the caliper manually - visually aligning it - so that the pads clear the rotor. The open-top design of Hope brakes allows me a good enough view of the rotor/pads to do this, but for other brakes the LPT method may have to do. Once you understand how the caliper needs to be aligned for best performance, you can find the best way to re-align your specific brake."
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is it difficult to remove the pads? how would i go about pushing the pistons back to be flush with the calipers? sorry about all the questions but i really want to try and sort this myself without running to a lbs :)
An old bike i had could only fit 160mm , is that your problem?
Its odd that the rotor rubs the mount. Does that frame weld push the mount outwards ?
You dont have spacers between the mount and the frame do you?
Like you cant change where the mount is, that just bolts on , and that rubs the disc so its a bit odd.
Also push pistons back with pads in using a flat large screwdriver and be gentle.
To remove pads take out the pin/bolt through them you see in pic 2
An old bike i had could only fit 160mm , is that your problem?
Its odd that the rotor rubs the mount. Does that frame weld push the mount outwards ?
You dont have spacers between the mount and the frame do you?
Like you cant change where the mount is, that just bolts on , and that rubs the disc so its a bit odd.
boom i think you got something, i have little spacers in between the bolt and frame :) will take em out later and see it that was the problem, they only look about a mm or two thick would this cause all this?
If your rotor is rubbing your adapter then it has nothing to do with centering the caliper over the rotor...
From what I can see (and I know this is obvious) the adapter is too close to the rotor.. make sure the adapter is fitted correctly.. as in its the right way around and the right way up.. they usually have a 'FWD' or an arrow on them to show which way is up.. the side with the arrow on it is usually on the inside.. ie facing the rotor..
Make sure you don't have washers / spacers in between the adapter and the frame.. if you do then take them out.. that will give you more clearance..
Also as a quick fix, you can add a washer / spacer onto your axle to move the adapter away from the rotor.. that's if your axle allows it.. if its a cup and cone type then you should have no problem sticking in a 2mm washer...
An old bike i had could only fit 160mm , is that your problem?
Its odd that the rotor rubs the mount. Does that frame weld push the mount outwards ? You dont have spacers between the mount and the frame do you?
Like you cant change where the mount is, that just bolts on , and that rubs the disc so its a bit odd.
Also push pistons back with pads in using a flat large screwdriver and be gentle.
To remove pads take out the pin/bolt through them you see in pic 2
point and laugh at the idiot :) thats what it was as far as i can tell, i had two little washers on the screws that came with the brakes which where causing most of my problems, the wheel actually spins now so thats great, i can still hear a little rub so il go about fixing that tomorrow with all the great suggestions on this forum, thanks guys ye where all a great help
