[CTR]

has anyone used them on a mountain bike, they seem like they wouldn't fill with mud and the low profile design doesn't look like it'd clip rock very easily? comments?

http://www.coombe.com/coombe_pro_pedal_system.html

 

[Squeak]

Don't know if they would fit on an MTB shoe without some modifications.

If your worried about mud, try Time ATAC's or Eggbeaters. They work really well.