Is this a common thing? Suspect I overheated my rear brake in the Alps last summer and the rear rotor has a crack in it.

Looks like it’s just one of the three-layer ice-tech rotor, so it’s not fallen apart. It’s bad enough though that it cut a gouge into one of my pads.

Just wondered if this is a common problem at all? Are Shimano likely to give me a free replacement? Have to admit I was a little unsure initially about the idea of a three layer metal sandwich in something that gets hot – different metal expanding at different rates. I wonder if that’s what caused this.

Yes it seems common. Ze German review mags made a regular thing of melting Ice Tech rotors on alpine descents. There is a big thread on mtbr although I can’t find it quickly. It is worth asking for a replacement and see how things turn out (the shop you bought from will warranty the replacement, not Shimano). No rotor should crack unless it has taken a big ol’ whack IMO

Wow.. had a bit of a Google, lots of reports out there. Will replace with a standard rotor and see what my LBS say about the cracked one.

Tempted to replace the front one now, but as that’s not discoloured with heat it probably gets significantly less hot.