I have 1.8mm thick brake disks on my unis. For a new brake disk I’m debating whether to stick with 1.8mm or buy a thicker one, at 2mm. As someone who has no clue about disk brakes I’m wondering if such a change could cause issues with the clearance between disk and brake pads. There’s 0.2mm less space (or 0.1mm per side). On the other hand I think that the calipers of disc brakes do adjust themselves to the thickness of the disks. If that’s true, there shouldn’t be any issues.
Can anyone confirm?
Yes, but only in a certain range. Thicker disk+new pads may mean that there is not enough clearance even with the pistons pushed back.
I’m pretty sure I’ve had 2 mm rotors with shimano brakes designed for 1.8 mm rotors at one point and no bigger issues other than slightly excessive rubbing for the first kilometer after a brake change and a quick google found others with the same experience. You can check for your specific brake if there are forum threads out there, but I think for 1.8 to 2mm worst case you’d have to do some very minor sanding to the pads and/or live with a rubbing brake for a ride.
In theory that would give you 0.2mm more allowable wear on the disk + some extra stiffness. Not sure how much that matters in reality.
Thanks for your input. I kinda was hoping that they have a margin with new pads and that the difference would be taken care of by that margin - so basically they would stay at the same distance to a 2mm disk than they would to a 1.8mm disk.
I hate it when the disk touches pads when I‘m not breaking (I even hate the ringing noise the disk sometimes makes when e.g. I push the uni down stairs and it bounces off the steps).
I guess I will go with 1.8mm to be on the safe side.
The only thing I can add is that Shimano have a larger clearance to the disc than is standard on callipers due to their progressive system… so I guess that is how they got away with it.
They do as soon as you’ve worn down the pads by 0.1 mm. It’s really only the very first wear in, where you may (depending on the specific brake) have more rubbing than usual.
As the pads wear, the rotor to pad clearance will become the same regardless of rotor thickness, it’s mainly dictated by how the manufacturer designed the seals on the pistons.
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