Originally Posted by
Freakin'Chickin
Urbanknight, is your terrain very rocky/rooty or loose? I also run a Panaracer Fire XC Pro on the back wheel (usually on a Hutchinson Python but now too pricey to buy again), and I am having traction problem on steep uphill of loose dirt or on exposed granite rock. I run around 36 psi, which maybe a little high, I dunno, but I feel that for the rest of the terrain, 36 is good (tube tires, not tubeless), and I'm on a hardtail, so tooo high is hard on the multiple roots, and too low... well. And that Fire XC Pro tire feels like a real tractor tire, but it's a 2.1, I should try a 1.9 maybe? My plan is to swap it for a IRC Serac XC which I have in front right now.
Rocky, but not very rooty (very few trees where I ride), with very little loose sand. The one spot I referred to above actually has a lot of loose chunks and some roots. Most other places around here (including the rest of that trail) love my Vredestein Black Panthers. The traction is great on slick rock, especilly with lower pressure. The Fire XCs are just as good traction-wise in this stuff, but just aren't nearly as fast when I'm cruising the smoother sections.
Narrower tires are hard to find a good pressure on, because too low means pinch flats. 36 seems a little high unless you're a clyde, but only you can decide for sure. I wouldn't go narrower. The only thing keeping me from going wider is my 22mm wide rims.