This past weekend I was riding some technical single track. Talk about working on your bike skills. Anyway...

Some the sections had rock faces that needed to be climbed. I was finding that my rear wheel was spinning out, maybe half of the time. The rock faces were not wet (at least as far as I could tell) so I'm curious why my rear wheel was spinning out. Could it be I was in too low of a gear? Does temperature affect the bikes ability to climb up rocks?

Also, I was having a lot of what I am calling rear slide-outs. I'd be riding up over something - a root, a rock - and the rear wheel would slide over to the side and down. So long as I was pedaling I was able to keep the bike moving forward. Probably just bad route picking on my part.