Optimum gearing for XC with 21 inch rear tires?

[CorvetteZ06]

Hey guys, was wondering what gearing your running with 21 inch rear tires for cross country/harescramble racing?

i have always ran 14/38 with my 18 inch rear tires for mx, but will this work with 21 inch rear tires in xc racing? Thanx in advance.

[skyhighatv]

i would try to gear down,prob just switching to 13t in the front would work well.

[86250rrider]

i would try 13/39 with that. what pipe are you gonna use? type of port ? i run 13/38 with 20 inch with a type 6 and a c-leigh low-mid port. i tried a 12/38 ....waaay too nasty to control in the tight stuff! if you dont have a type 6 ...get one.:macho

[Rich250RRacer]

Originally posted by 86250rrider
i would try 13/39 with that. what pipe are you gonna use? type of port ? i run 13/38 with 20 inch with a type 6 and a c-leigh low-mid port. i tried a 12/38 ....waaay too nasty to control in the tight stuff! if you dont have a type 6 ...get one.:macho

I personally don't like the type 6, all low end with some carry over into the mid-range. It all depends on the type of tracks you run, my locals are like the GNCC's with alot of wide open stuff. With the type 6 you're short-shifting, and don't pull enough top end. My main quad uses a stock pipe (which works amazingly well with my motor set-up, nice smooth power with no hard hit), my other 250R uses the Paul Turner race pipe. It has decent bottom end, stong pull in the mid-range, and carries over nicely into the top end.

[MossboysRacing]

I run 12/39 on 20" Razr 2's. My motor has a mild port job and i run a FMF fatty. I have had lots of success running that combo, and i love the lower gearing in the tight stuff.

[JM317]

Try 13/39 gearing...I have a primary drive gold x-ring chain and sprocket kit for sale with about 3 hours of use on it that you need.:D