Took my new Jamis bike on another real tough trail, probably the toughest one yet and it'sobvious I need bigger more aggressive tires than my stock 2.0 Hutchinson that my bike came with. I'm going at least 2.1 in the rear and a 2.3 up front. I'm actually more concerned with my rear because I'm really sliding there. I've had to lock up my rear wheel several times on some intense downhill and there is no bite whatsoever. I need something that is going to grab. Plus, going up hill, I'm spinning out. My wheels now aren't up to the task. I know most people go thinner in the back but I 'm more concerned with traction. So far I looked at the WTB tires and I really like their aggressive tread, so I'm really leaning towards them. What do you guys think?