I know a lot of people are haveing belt issues with the Xp and I'm not saying this is a fix, it's just another belt you can run. Took the spare belt off the 98 Summit X, which for me is a Gates Extreme 38X4360 and it "seems" to be the correct length. I know it is slightly narrower and I have not had a chance to measure the length. I tossed it on and adjusted my ride height and will try it tomorrow. I would assume, just like the clutches that have used the Gates in the past, they will require more weight for the harder compound Gates. Not sure what Ski-Doo charges for the oem belt, but I think I paid about $55 for the Gates with an unquestionable warrenty.