XR250 -Sprocket sizes and ratio info needed pls

[Blake]

I have an older XR250 (92 or so), anyways it was set up with a huge back sprocket for offroad but now its mainly a road machine. The back sprocket has 46 teeth. I wanted to get a smaller one before my last ride but at the last minute it fell though. In a scramble, I ended up coming up with a 1 tooth bigger front sprocket instead, 14 up to 15 teeth. That did help a bit but not enough of course. Now I can just barely cruise at 100km/hr comfortably but a bit slower feels better. The motor just works too hard at these speeds although it will certainly go faster. Before getting the 1 tooth bigger front sprocket, 90km/hr would be as fast as it wanted to cruise comfortably. The gears are spread out a bit more now but still not enough.

Can somebody tell me what a typical set up would be for a bike like this. I'd preferably like to keep the front 15 tooth since I have it now. So what size do you recommend for the rear? I need more top end but don't want to loose all the grunt either. Thanks for any info!

Blake

 

[dirthonk]

I need more top end but don't want to loose all the grunt either

a predicament there of many an xr rider.

i run 14/45 on my xr, offroad that is. i used to ride it on the road once upon a time, think i ran 15/42. although that was with a big bore in it.

i believe stock is 14/39 in road trim. maybe you could try that.

if you still need more torque try grabbing onto the handrails of the nearest sawngtaew as you leave the traffic lights for some extra acceleration!

regards

 

[Blake]

Thanks for the info! That was about what I had in mind but wanted to get a second opinion. I already have the 15 up front, so I was thinking about a 41 or 42 in the rear. I think a 14/39 is about equal to a 15/42 as I beleive 1 front tooth is equal to about 3.3 rear teeth if I am not mistaken? So if you think that is stock I shouldn't go below a 42 rear since I have a 15 front already. Unless somebody else has any more insight before I get to the shop, I think I'll go ahead with the 15/42 setup! Again, thanks for the info!