Just found out Shimano hydraulic brake rotors have a thickness spec printed right on them

Was swapping pads on a customers MTB in Denver yesterday and noticed 1.8mm stamped on the rotor - never realized they actually put that there for wear limits. Anyone else only find this out after years of just guessing when to swap rotors?

3 comments

3 Comments

gavinwells1mo ago

Stick a caliper on them and check for the specs, don't just eyeball it. I've seen rotors that looked fine but were way under 1.8mm and would've cooked the pads or warped on a long descent. Once they hit the printed number, swap them no questions asked. Better to spend 30 bucks on a rotor than deal with a customer coming back with a squealing mess or worse, a crash from brake failure.

king.robin1mo ago

Gavin, you said "once they hit the printed number" but what about rotors where the printing is already worn off or faded? I've got a couple older ones where I can barely read the spec anymore.

diana_west271mo ago

Wait, aren't most Shimano rotors actually 1.8mm new and the wear limit is usually 1.5mm? Might wanna double check that number before you start swapping things early.