how much would i loose

[400exrider04]

how much speed would i loose if i went from a 20in to an 18in rear tire

[1badex]

i dont know how much speed you would lose but it might spin more than your 20in.-are you ridin mx or trails?

[400exrider04]

im setting my bike up for mx

[roostin_dale]

18's are a must for motocross! You will lose prolly a few mph's but no big deal. You will pull out of the corners quicker, jump better, and they are lighter...