Tire size

[EXMARK]

If I go with a smaller or larger size tire on the rear will it hurt any thing? I read where a guy went to a smaller tire and he had oil pushing out of the breather, something about higher rpm range.

[400exrider707]

NO, it wont. If it bothers you, then you can always change sprockets to compensate for tire changes to retain close to stock gearing.

[EXMARK]

Which sprocket (or sprockets) would i need to change if I went to a 18 inch tire? I have a new front 14 tooth sprocket I could put on.

[underpowered]

you need to go teh other way. if you put 18" tires on you will lower your gearing, so you need to put either a larger front sprocket on or a smaller rear to get back to stock gearing. Going dow to a 14tooth will lower it even more an dyou will gain acceleration but lose top speed. going from a 20 to an 18 intall tire wont hurt anything. the gearing change isnt that larg of one, only about a 10% change. To compensate you need to go down to a 36 tooth rear sprocket to give you close to stock gearing.

[kd5sfq]

Smaller tires takes about 5mph off the top end... Going up one tooth in the front and two or three in the rear gives it back.

Personally, I like keeping the stock gearing with 18 inch tires... There is more torque to the wheels but you have to shift faster. It's hard to hit top end on an MX track anyway.