Like others have said, they are the same...My problem is that I do woods riding here with my friends, but open trails/dirt roads/hills and fields at my property in Eastern Wa, so I am trying to find a good in between. Hopefully the 51T will help, but if I have to go to a 12T on the front I guess it wouldn't be the end of the world. I already want a 6th gear on the thing as it sits though, as I have found myself in 5th just cruising along wanting a few less revs at speed. Oh well, I bought a YZ not a WR, and have to make the best of it since I'm not flying 100' in the air off a triple! Beatcoaster, any idea if the internal gear ratios changed from the 06-09 spec to the 2010 spec? I went 1 tooth smaller up front my 450 and its still not low enough for the real tight stuff. I had my 426 at 13/52 and it was a beast in the woods, to get the same results on my 450 I'd need to go 12/52 or 13/55 because the internal ratios changed from what the 426 had. I'm running 12/49 now and I'm getting quite a bit of wear on my X-ring chain from the TM Designworks slider, so I think I'm gonna have to buy another dang chain and a 55 tooth rear.