north_of_55
New Member
I have a 2013 with around 57K km on the clock.
Ever since I bought it (around a year and a half ago) it has had - it's hard to describe - what feels like warped discs in the front. But I don't really feel any feedback through the brake lever.
Rolling to a stop if feels like the coefficient of friction on one half of the front discs is higher than the other... so as I roll to a gentle stop under braking the nose of the bike is diving intermittently - as though I am squeezing and releasing the brake. At higher speed/harder braking it is not noticeable.
I have rotated the disc bobbins with brake cleaner, I have cleaned both calipers as well as the pads and discs. All of the pistons seems to move freely. The pads appear as new, the discs have no visible sings of wear, uneven contact with the pads or checking.
Over the coming days I plan to rig up a way to mount my dial indicator to my fork so that I can check run-out.
As a Professional Engineer and an experienced wrencher - I am a little stumped.
My main question at this point is about the floating discs. I have seen several forum posts about floating discs and the consensus always seems to be that the disc should be free to move slightly (axially and tangentially) if things are in good shape.
The discs on my ST seems very much rigid. The bobbins turn with light pressure on a wrench (with a 6mm bolt and nut snugged) but there is no way that they could be rotated with fingers alone (as I have seen several people suggest they should).
How much movement should the disc have with respect to the carrier on an ST? Are anyone's bobbins movable by hand?
Ever since I bought it (around a year and a half ago) it has had - it's hard to describe - what feels like warped discs in the front. But I don't really feel any feedback through the brake lever.
Rolling to a stop if feels like the coefficient of friction on one half of the front discs is higher than the other... so as I roll to a gentle stop under braking the nose of the bike is diving intermittently - as though I am squeezing and releasing the brake. At higher speed/harder braking it is not noticeable.
I have rotated the disc bobbins with brake cleaner, I have cleaned both calipers as well as the pads and discs. All of the pistons seems to move freely. The pads appear as new, the discs have no visible sings of wear, uneven contact with the pads or checking.
Over the coming days I plan to rig up a way to mount my dial indicator to my fork so that I can check run-out.
As a Professional Engineer and an experienced wrencher - I am a little stumped.
My main question at this point is about the floating discs. I have seen several forum posts about floating discs and the consensus always seems to be that the disc should be free to move slightly (axially and tangentially) if things are in good shape.
The discs on my ST seems very much rigid. The bobbins turn with light pressure on a wrench (with a 6mm bolt and nut snugged) but there is no way that they could be rotated with fingers alone (as I have seen several people suggest they should).
How much movement should the disc have with respect to the carrier on an ST? Are anyone's bobbins movable by hand?