schools of caliber alignment

dbmnk

seems to be two of them:

The Shimano manual states that you should press the lever to align the caliber according to the rotor, and then bolt it down.

My local mechanic states that you should always align the caliber so that the rotor seats exactly is the middle of the caliber groove.

In the ideal world this would give the same result, but it just doesn't - probably due to uneven piston pressure, skewed rotors and irregular mounting studs.

Using my local mechanics tip, I get squeal and rotor bending.

Using the Shimano manual, there seems to be caliber position disagreement between the free moving and bolted down.

Which school would you commit to?

Should you face down the post mount studs in order to rectify some of the caliber misalignment?

benpinnick

Where you have a good degree of 'natural' adjustment in the mountings, such as with Avid's tri-align, then the brakes on and tighten approach works well. If you have less free movement in the mounting, then I would start with that, then adjust from there.

02gf74

actually a bit of both - I do the "loosen bolts apply brake" first then if thjre is some rub, and it usually is tiny, I will nip up the bolt and adjust by eye. then tighten down.

There should be no need to face post mount since there are dish and cup washers, a pair on each side of the caliper mount that allow the caliper to be fitted at a slight angle. If you don't have these, this could be contributing to your problem.

oh, and it is CALIPER!!!

getonyourbike

02GF74 wrote:

oh, and it is CALIPER!!!

beat me to it

ricardo_smooth

Hope/Formula tell you to align the caliper

Shimano/Avid tell you to squeeze the lever and tighten. I normally do it whichever way the manufacturer reccomends! (my saints line up better with the lever squeeze method)

gtd.

I use the Hope technique as shown in this video

First make sure the disc is central to the caliper

Then centralise the pistons to the disc.