Gearing for road only!! 15 front and ?? rear??


I have two tire set ups. One for up north riding in Michigan with the boys and the other for 80 % street 20 % trail when I an around home. I have track masters on both and are a DOT knobbie. The 15-49 I ues for dirt, but when I am on the road it is running to many rpm,s for crusing at 60 mph or any faster. I want to use the 15 for both so I just need to take out a couple of links to switch tires back and forth. Does anybody know how many teeth to get for the street rear sprocket?? This is on a 03 WR 450 dual sported.


Hiya, Check out this site, They have a gearing calculator which calculates your speeds depending on the different front & rear sprocket configurations. I found it extremely handy.

Good luck

I run 15/42 for a 160/60-17 supermoto tire and do a lot of highway riding. This equates to 15/45 or 15/46 for a 110/100-18 tire. The motor is happy cruising in 5th from 50 to 75 mph. The rpms are about 5100@55 mph, 6000@65, and 6900 at 75.

I've ridden as heavy as 16/44 with 18 inches rear wheel and Siracs tire from the big Michelin.

I am also very happy with 15/42 for my supermoto 450. I believe that the 15/46 with the 18'' rear rim will be just perfect!

i run 13/50 off road

and 15/48 on the road

i wouldn't go taller then that if you are going to see ANY off road!

By the way: when I installed the vapor computer with water temp gauge, I found out the water temp on the highway is only 60 to 65F warmer than ambient!

My water temp was only 140 to 145F when it was 80F. That's probably bad for lubrication since the oil will be thick while you are running at relatively high rpms combined with real operating loads.

I blocked off about 60% of both radiators and now am getting 90 to 100F above ambient, which is where it should be. Sitting at a stop light for 5 minutes isn't so good, but wasn't good before either.

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