I'm not sure anyone can really say what the best belt is. I'm still trying them all myself. I have many 8JP's, 8DN's, Ultimax & Dayco belts. I have enough to last me the rest of my snowmobile life! My "go to" is the XS Ultimax myself for trail use as I believe it to be the strongest, but I can tune for any of them and have setups for any of the belts in on the list. I'll even swap belts for the conditions for the day along with helix and primary weight changes if the day changes much. If it warms a bunch, I'll swap in a 8JP as the compound is better suited to remain more consistent for the heat. I've yet to run the Dayco Redline, so looking forward to trying it too. Maybe it will react different and be the one to have, who knows. We don't get snow anymore to be able to put many miles on at all.
What's belt is better for say longevity, may not be the best for ET or drag racing, the best one for speed is going to be different again. Maybe theres one out there for strength that refuses to blow, but it wont ET or run speed. So to say which one is better..... Well better for what? What's the one thing your looking for? Because you can't get it all in one belt. Just not going to happen. One is always better at one thing than another. I aways ran different belts for drag racing than speed running, and there's a reason for that. Harder belts typically are the best for ET, but you need to pinch them tighter with different clutching. Some people think "sticky belts" are better for ET or performance, but thats not always the case. I've typically found hard & stiff belts best for ET, but you just have to pinch them harder, they are also more consistent with heat and temp range. For speed I like belts thinner and more flexible, but they just wont ET for crap. There going to be a tenth off at least on the timers.
Bottom line, what works best for one guy, is not going to work for another, also the clutch recipe or tendencies for one man is going to be better for one belt over another. Bottom line there is no magic belt thats going to work for everyone all the time. Only they testing on your clutch setup are you going to find what works for you, and I'm guessing no one hear really test belts on the timers or radar unless your racing competitively. At least then you'd have consistent and good traction and running conditions like Ice to keeping things consistent from run to run. Running in snow and spinning isn't going to tell you squat when making changes to clutching and belt changes.
