Sprocket ratios

Can anyone give me some solid advice or direction for selecting the right sprockets for my type of riding (hare scramble/trail).

Im looking to replace both sprockets and the chain and want to achieve more power out of the turns and low end.

Please give me some opinions or references.

2002 XR250


Edited by SCSURFER
left subject matter out

what gearing do you have now?

Dropping 1 tooth up front is equivalent to adding 4 in back. Very noticable. That's lowering the gearing so you're turning higher rpm's at any given speed. And have more power at lower rpm (low end).

cheap to drop 1 up front and see if that suits, if not, then change back sprocket for fine tuning. A big drop in overall gearing would be going 1 tooth smaller on front and adding 3 or 4 teeth on back. That is going to be a big change and really change the bike a lot. You'll think you've got a big bore down low, but then run out of gears really fast on top.

Edited by MindBlower

is 1 to 3 ration front to back, Renthal has this chart to compere changes you can do to achieve gear ratios..


is always good to make changes in the rear sprocket, for clearances in the engine cases..

no suggestion for the xr250 from me though know about the 400...exact numbers you may get in the off road riding forum

dont forget going with a bigger chain if you go bigger

On my stock XR250s and also the 280s, I always used 14/48. This eliminated the stump-puller 1st gear and made it usable, allowed use of 3rd gear in the woods rather than 4th, reduced shifting, decent speed on road sections without screaming the engine.

Yeah the equivalent is 1 front tooth to 3 rear teeth, more or less. Try a 1-tooth smaller front and see what it does for you. If you want to go even lower then add 2 or 3 to the rear. Any lower would make 1st gear kind of pointless unless you are trying to climb vertical sections. Oh and the smaller front will wear out your chain slider (top of swingarm) a little faster but this would be reduced if you end up using a larger rear. If in doubt about the chain length to get, go longer since you can always remove a couple links.

Thanks to all you guys for the great info.

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