My LX M585s have been great brakes, but utter pants in temperatures close to freezing. Apparently the rubber in the seals hardens up in the cold and the pistons consequently fail to retract.

The Shimano service centre are suggesting M595 brakes as an equivalent but when asked whether they could guarantee that these would function in the cold, the reply was that they’d had no reported issues; a political answer I suppose.

So, has anyone run these brakes at freezing or below and do they work? Depending on cost I may just get the calipers.

I ran a pair right over the (really) cold snap/Xmas etc with no issues…saying that I also used both Hope and Avid brakes with no problems as well.

tundra-esque by twinklydave, on Flickr

That sounds encouraging. In a thread some months ago (during the cold snap) I was told that this was a known issue that should have been fixed with more recent brakes, but people were also experiencing issues with later SLX and XT models, so it may still occur.

used mine through the cold spell in december, no problems at all.