Need help with shaft drive rear end ratios. 250sx

[AtcFactoryRacer]

Im building another 250sx this one is going to have a 300 fourtrax engine im gonna run 22' holeshots, i am looking to get the most top speed i can. My question is which honda shaftdrive model has the tallest rearend ratio. I know the stock 250sx is taller than the big red and the trx 300. Maybe a newer sportrax 250ex ring and pinion would swap? or an older trx 250 is taller? I dunno help me out guys.

[TheRealFatShady]

I believe they are all higher than the SX, and I don't think any of the newer ones come close to fitting.

You can always put 450 Foreman gears in. One guy over at Highlifter.com did and got a lot of top speed on his TRX300.

[AtcFactoryRacer]

I wonder how i can find out the actual ratios, maybe there is a vehicle spec sheet that lists the final drive ratios. I know for a fact that a bigred has a lower ratio than a 250sx, and i read that alot of bigred owners were swapping trx300 gears because they are even lower to help run bigger mud tires. Since the trx300 is geared low adding 450 foreman gears would probably put me the same as my stock 250sx ratio going by the tip you gave me. Man swapping sportrax 250ex gears in would be awesome if it would be possible, my buddy has one and he outruns my other 250sx but i am also running 20" tires on that bike

[250Eddie]

Gotta look becuz the sx is a little bit bigger gearing them the big reds

[TheRealFatShady]

Most manuals or data sheets should have those ratios.

http://forum.highlifter.com/Gear-ratios-for-every-4x4-Honda-ATV-ever-built-m2431196.aspx

All the pics with numbers are now gone it seems, but some useful info in there.

And the guy using the 450 foreman gears in his TRX engine is here:
http://forum.highlifter.com/tm.aspx?m=2372108&high=TRX300+Gear+reduction+best

I thought the TRX engine stock is close to the SX/ES/TRX 250 engines, and the rear end was closer to that of the ES rather than the SX as far as final drive gearing. People needing lower gearing usually use a few modified gears out of a TRX 300ex or 250x sport quad.

Also here is the numbers for the ES and SX:
http://www.3wheelerworld.com/showthread.php?63332-250es-250sx-heres-the-diff-difference-in-the-gears

One other differential that may bolt on (full rear end would require some work as I think it had two shocks) was the TRX350 - 1986-1989, similar top end as the 350x.

[AtcFactoryRacer]

thanks for the info guys, from what i read my 250sx has a 10 tooth pinion, and a 34 tooth ring gear, which is a 3.4 ratio. I would like to have an 11 tooth pinion, and a 33 tooth ring gear. which would give me an even taller ratio. Anyone know who is could make me a custom set.