Rim Race Face Arc Offset 30 27.5'' 28h - GreyRim Race Face Arc Offset 30 27. 5'' 28h Grey Well Rounded We tapped into our collective know how to make this rim stronger, and better balanced than anything else on the mountain. Asymmetrical design creates perfect spoke tension while 6069 alloy provides a jaw dropping strength to weight ratio. No, You're Out Of Line We found that by offsetting the nipple bed on these rims, we can optimize spoke tension and make the ARC wheels stiffer and stronger.