Oh yeah....
you'll notice the difference. Dropping a half pound of rotating weight per wheel will certainly be noticeable. But what will also be noticeable is the difference in ride and handling. You'll be giving up some traction, float on loose or sandy soil, and you'll need to run quite a bit higher pressures to keep from pinch flatting. Also, a narrower tire will ride harsher at a given pressure than a wider higher volume tire at the same pressure.
So choose carefully weed hopper. Lighter narrower tires aren't always better! You'll be AMAZED at the difference in width and volume between the Fire XCs and the Nevigals. I run Nevi 2.1s on my FS and 2.1 Fires on my Hardtail. Even though they are both 2.1s the Nevis are noticeably bigger and perform noticeably different. And they are meant for different riding styles as well. The Nevegal handles agressive XC and Trail riding much better. The Fire makes a good XC tire, but lacks a bit when things get agressive. I can't imagine using the Fire XCs for AM. Just not enough volume for that type of riding. But it depends on how you ride more than anything else. Personally I'd go with the 2.1 Nevigal DTC as a minimum for AM riding. They're about 100g lighter than the 2.3s, and you'd likely notice that as well. And by the way, the Fires run closer to 610g "real world" weight for the folding bead model.
Anyway, your choice. You'd certainly notice the difference in weight, but I think you'd notice the difference in performance (negatively) even more. The Fire is a good all around XC tire, but IMHO it won't cut it for All Mountain.
Good Dirt
