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View Full Version : Went from 20's to 18's, how do i compesate gear wise????


Wired
03-19-2003, 04:11 AM
i recently got 18 inch tires on the rear end going from 20's. i noticed in geared way too low. i can hit the rev limiter in 5th gear no problem. sooo.... how do i compensate for that with gearing? i know to go with a smaller rear sprocket but how many teeth to get back to where i was before? its running stock gearing, front and back. any sugesstions would be great. isnt it like 3 teeth gained on the rear for every inch lost in tire size?
Ralph
03-19-2003, 04:17 AM
go one up on the front (16th) and u will just have to grind the case saver a little to make it fit, or u can go down 2 in the rear(36 in think)
03-19-2003, 04:44 AM
JOn...a 15/36 is the best setup for 18's i think...that's what I run and it's awesome...the 16 up front is just to large of a jump i think....with the 15/36 you loose nothing..only gain topend...;) Trust me you'll love it..:D
86atc250r
03-19-2003, 04:51 AM
15/36 and 16/38 yeild almost exactly the same ratio. If you don't need a rear sprocket and can take up a little chain slack, the 16/38 gearing would be the way to go - cheaper, easier on your swingarm guard, etc...

See here:
http://home.earthlink.net/~gellett/400ex.htm
03-19-2003, 05:11 AM
I'd rather have a good case saver up front though...;)
03-19-2003, 05:44 AM
id like to have a case saver:grr
86atc250r
03-19-2003, 05:50 AM
Keep your chain properly adjusted and you won't have a problem :p

Honestly, I've never had a chain throw on my 400EX - I also don't run it with bad bearings or an improperly adjusted chain either.
QuadTrix6
03-19-2003, 06:40 AM
RICO is correct stick with stock gearing for MX
86atc250r
03-19-2003, 06:52 AM
:huh

15/38 is stock...
K_Fulk
03-19-2003, 06:55 AM
Get a Baldwin case save they work with the 16 tooth sprocket.
But like gabe says if you take care of it you won't throw a chain.
WildCatRacer
03-19-2003, 12:44 PM
I would gear up about 2 or 3 teeth. I think 1 tooth bigger in the front is close to down 3 in the rear. I'm sure cody or your brother has a rear sproket you could try. I have a couple different sizes you could try too if you wanted. I geared up about five teeth when I went from 22s to 18s on my 300ex.
QuadTrix6
03-19-2003, 12:47 PM
Originally posted by 86atc250r
:huh

15/38 is stock...

sorry about that i dunno what i was thinking. i meant to say yea rico is right stay with 15-36 not stock gearing. i have stock gearing on right now and i think its a little to low so im gettin all new sprockets and a chain and im gunna try out 15-36
Mxbubs
03-19-2003, 02:34 PM
15/36 without a doubt
Cole
03-21-2003, 04:57 AM
I got new 18" Kendas for the rear also. Where should I get my new rear 36 toothed sprocket from? What brand?

thanks.
Cole
03-21-2003, 05:18 AM
I just ordered the 16 front from C and D. Renthal. Ill try that out first.
OutlawEX
03-21-2003, 11:09 AM
Originally posted by Mxbubs
15/36 without a doubt
WildCatRacer
03-22-2003, 01:22 PM
www.sidewindersprockets.com
muff
03-22-2003, 01:34 PM
anyone else other than sidewinder make 36? theres nothin in rocky mountain....sidewinders site isnt workin
ROGERS
03-23-2003, 06:07 PM
but I think it might help. It kind of tells you which setups yield the same/ better ratios.

15/38, 20" tires = stock
15/38, 18" tires = 10% lower*
15/37, 18" tires = 7% lower*
15/37, 20" tires = 3% higher*
16/38, 18" tires = 3% lower *
16/38, 20" tires = 7% higher*
15/39, 20" tires = 3% lower*
16/39, 20" tires = 4% higher*
16/39, 18" tires = 6% lower*
14/36, 20" tires = 1% lower*
14/36, 18" tires = 11% lower*

*= than stock

Check JL for sprockets. R's, EX's, 350X all use same rears, but not fronts.