Chainring Size (teeth): Rear Cog Size (teeth): Rear Wheel Size (road): 24x1 26x1 None 700x20 700x23 700x25 700x28 700x32 700x38 27x7/8 27x1 27x1 1/8 27x1 1/4 Rear Wheel Size (ATB): 26x1 26x1.25 26x1.5 None 26x1.95/2.0 26x2.1