Quote Originally Posted by Catrin View Post
I've had several hard falls this summer due to my rear wheel spinning out on dusty curves on the trail. If my memory serves me correctly, each time I was climbing and thus my weight would be more forward on the bike.
Do you mean that you were climbing, the rear wheel lost traction, started spinning, and the loss of forward power made you crash? If so - learn to recognize the situation, be prepared to slam on the brakes and plant both feet on the ground.

Or do you mean that were going around the corner and the rear wheel slipped sideways to the outside of the turn? This probably means you were leaned over too much. When I was riding a lot on knobby tires, somehow or other I learned to keep the bike somewhat perpendicular to the (road or trail) surface. (I think this is because once the front tire skidded sideways when I was leaned over going around a fast corner.) If the speed of the turn required a lean, I'd move my body over, but keep the bike mostly upright. Sheldon et al. say not to do this - it imparts significant non-normal forces in the bike. However, some tires simply aren't able to grip off of perpendicular. Or they might deform, letting the rim roll towards the outside. In summary, be constantly aware of how your tires are contacting the ground and don't ask more of them than they are able to perform.