I have been running the stock 14-48, and have been pretty happy with that gearing for trail riding, but ideally, I'd like a little lower gearing for the singletrack and higher gearing for longer DS rides. I've been looking at the gearing charts, and I'm wondering if I can run a 13 and 15-tooth counter-shaft sprocket with the same chain. I'm thinking that a 15/47 might work out really well for the majority of my riding and I know I could swap that for a 14-tooth sprocket without any problems, but I'd like to be able to throw a 13-tooth counter-shaft sprocket on there to go ride some of the tigher, technical singletrack. I called Dirt Tricks, and the guy I talked to said he thought that would work, but wasn't 100% sure. So, can anybody tell me whether or not I can jump two teeth up front? I also have two sets of wheels. They're both dirt wheelsets, but one is a dedicated dirt setup and the other willl probably be outfitted with dualsport/street-oriented tires most of the time. Since I'm going to need to buy a second rear sprocket anyway and I'm already planning on swapping out front sprockets, should I get the same sized rear sprockets for both wheels or should I run different sized rear sprockets for each wheelset? I know I've read something about a couple of different front/rear sprocket combos that you can switch between without having to reposition the rear wheel too much, if at all. Pretty sure it was related to the guys that convert from dirt to SM. Running the same size rear sprockets would allow me to get the full range of gearing out of either wheelset by switching between the 13/14/15-tooth front sprockets, but I see a few downsides. Namely, that the rear wheel would have to be positioned pretty far back when I run the 13-tooth front sprocket. Then I guess there might be some accelerated wear because of the smaller front sprocket, but I'd only be concerned about that if it was going to affect the chain life. Should I get the same size rear sprockets for both wheels, or go with dedicated gearing for each wheelset?