2.1 works just fine. I'm running some IRC XC tires on my XM 321s. They're cheap and strong rims, the only question (IMO) is whether you want to go lighter: 2.1 tires == more XC riding yeah?spongstick said:I have a 575 and I just bought A pike I was thinking about getting 321 rim for the new pike,
but I dont no if you can put 2.1 kind of size tires on 321
Or maybe not. I'm 220# ready-to-ride, with a full-sus frame, and have had no problems with a 36 spoke XM 321 rear (32 on front). It's been bomb-proof for me so far. Had a longish race in the weekend with some IRC Notos 1.95s (not 2.1s, sorry) and it didn't get squirmy on the descents... but 2.35" does feel more "right" to me on these rims. That said, I tried some 2.1" Tiogas a while back that felt a bit dicey - it's the tires as much as the sizes, IMO.Brown_Teeth said:I ran those rims, front OK but if you ride hard the rear rim will take some attention. I run anything from a small 2.1 to a rather oversized 2.5 and all work well as long as you run them over 30 lbs, under and the narrower profile will cause some squirm/roll of the tire if you are over 200#. For a front rim its fine but I'd go bigger if you ride hard and are over 200#, have fun!