CRF's Only Forums

I can finally get 2nd and 3rd gear for all their worth - and finally passing power in top gear on highways...

more grunt, a bit higher RPM but well worth it... more fun off road and safer on the road.

I highly recommend...

Does this make the speedometer reading inaccurate?

yes, you will need to recalibrate the speedo with this product:

http://www.crfsonly.com/catalog/product ... ts_id/4746

ken

Speaking of needing to re-calibrate....My 2015 now has 13 tooth front and 45 tooth rear...I love the result of the Sprocket changes I did and I know my speedo is probably way off now....I'm not so sure I want to spend 75 bucks to re-calibrate....Anyone done a GPS check for speedo error on a RATIO similar????

The sprocket combo really wakes the bike up and the 2 and 3 gears are way better for off road use now!!!

GARY

Hi Gary,

Your new gearing is exactly 21.154% lower (assuming you have stock wheels and tire sizes still). You can see the difference in each gear by using our gearing calculator:

http://crfsonly.com/howto/gearing/motor ... ulator.php

Ken

Speaking of needing to re-calibrate....My 2015 now has 13 tooth front and 45 tooth rear...I love the result of the Sprocket changes I did and I know my speedo is probably way off now....I'm not so sure I want to spend 75 bucks to re-calibrate....Anyone done a GPS check for speedo error on a RATIO similar????

The sprocket combo really wakes the bike up and the 2 and 3 gears are way better for off road use now!!!

GARY

How many links are you running on your chain with the new sprockets? Looking at doing the same to my ride in the near future to squeeze some extra oomph out of it.

Hi! I'm about to change chain and sprockets; want to install 13T front but what do you all use for the rear? How many teeth?
Thanks!

I just picked up a 2015 crf250L from a guy after letting the KLR650 go. First thing I noticed was he's changed to a 13t. It threw the trans driven speedo off by 5mph which also would throw off the odometer and trip meter imo. I put it back stock and its just dandy. Afterall it is what it is, a 250cc street and trail bike. Does neither one fantastic but does both well enough to explore trails and streets. One mod will lead to another I've found out. My KLR was quite modded. But I'm finding with this crf critter the more mods you do its leads to spending to correct a side effects. I would think and I may be wrong but the rear sprocket change for lower gearing at the rear tire would be the best route. Changing the counter sprocket changes the ratio out put but leaving it and going to the tire end wouldn't change the transmission ratio output. I could be wrong but thats what I'm thinking with a speedo sensor in the transmission and software calibrated for that out put ratio. Someone chime in if my thinking is wrong. As I just got this bike and I'm still learning the techs on it.

If you change the front sprocket to the 13 tooth, do you have to also change the rear sprocket? Or can you just do the front by itself? Is the 13 front 48 rear combo the best for maxing out torque? I have a 2019 CRF250L Rally.

Welcome to the site !!

That would gear you down , and you can change either or both , the choice is yours , however , remember that certain combos will require either a shorter or longer chain , for example , if you used a 40 rear , then went to a 48 , you would need a longer chain ... your best bet would be to buy a 120 link chain , then you can make it to the length you need .... Look at this chart and compare what you have with different combos

The PO had a 13 on it, I put the 14 back on. Would like to try a 15
I can take the WR250 if it's gonna get serious (it's geared down).