rear sprocket is 40 tooth... ive got a front 14 and 15... ive got the 14 on now... just wanted to know before i cut the chain to fit the 14.. im too dam lazy to change to the 15 and check it out.. plus i have nobody to ride with and compare to.. tires size is 20" .. im sure this hasd been posted before but im havin hell tryin to fidn it with all the gearing post that have been made