gearing

[jlrenken]

i was hoping someone who knows alot about gear and how its works can answer my question. im running 14/39 and i was wondering if were to put 13/38 if that would be the same as running 14/41. the reason i ask is there is a track that is pretty much on a side of a ski hill and calls for alot of motor and 3rd does a good job for the most part but to get up the hill to clear a couple of triples 4th is where i need to be but when im in it its alittle boggy so i thought if i were to put a couple of teeth on the rear it would pull me out of the bog in 4th but i dont want to run a 41 in the rear. some input would be great. thanks
jamie

[jlrenken]

also does anyone else make a front sprocket for the ds

[ml450r]

Yes 14/41 and 13/38 is the same gearing. It will make third gear sign off sooner but give you more in the bottom of fourth.

[andiboy123]

im runing a 39t on rear and a 14t front with a 9"wheel with 18"tires and its great make curves on 3rd not loosing torqe and its open real good to jumps and hit 4th and fly away!!!!!!!!
by the way merill check the pm you send me the number was wrong

[fastford]

Not sure how mechanical people are but use driven over drive same as a car. For example 4.10's 3.73's or 3.55's. You divide your back gear by your front gear will give you a number. So a 13 front and a 41 back will give you a 3.15 and a 14 front and a 40 back will give you a 2.85. The higher the number the more bottom end. The lower the number the higher the top end. So a 4.10 will turn the drive gear (motor side) 4.10 times for every 1 tire turn. A 3.55 will turn the drive gear 3.55 times for one tire turn. Hope this helps.

[TNT]

Probably not enough worth your time or expense since the sprocket ratio’s are the same. Anything less than a 5-6% won’t be felt any more may be too much.

38/13= 2.92 old sprocket ratio

41/14 = 2.92 new sprocket ratio

(new ratio/old Ratio) - 1) * 100 = change as a percentage.

(2.92/2.92) - 1) x 100 = (+ 1 -1) x 100 = 0 % change.

Positive % trade top for bottom, negative bottom for top.

There will be some internal differences w/respect to transmission but not much. Play with this DS650 calculator to get a feel for it…you won’t see much of a difference for a fixed RPM and tire size.

http://home.earthlink.net/~gellett/ds650.htm

BTW: To change the torque or rpms for a given mph up or down its better to change the rear sprocket since going to a smaller front sprocket requires the chain to turn at a smaller radius causing more friction and wear. Its always a good idea to change the chain if it's not new when changing sprockets and visa versa since these surfaces are made to wear together with respect to the chain roller.