Sprocket change ????

[skeeter]

My son is getting ready for race season just wondering if I should drop down the rear sprocket or mess with the front ?? And what size would be best ?? By-the-way the quad is a 2001 Honda TRX90 !!

[newnick]

What kind of quad? Most will change gearing from stock.

[etondaddy]

We're running a 90 e-ton and going with 19-28 sprockets with 18" snowhogs.

Try this post
http://www.exriders.com/vbb/showthread.php?s=&threadid=265738

This was posted by Brad Loomis ;

18 - 32 = 1.78:1
18 - 35 = 1.94:1 Quickest ratio
19 - 36 = 1.89:1
20 - 36 = 1.80:1
19 - 28 = 1.47:1 Fastest ratio

The other real big contributing factor is tire roll out. The larger the tire the lower the ratio. So I take the circumference of the tire and divide it by the ratio for the final roll out.

19 - 28 ratio with 16" Snow Hogs ( 50" ) = 33.93
19 - 28 ratio with 18" Snow Hogs ( 54" ) = 36.64
19 - 28 ratio with 18" Duro Predator ( 59" ) = 40.04

So the 40.04 would roll out to the fastest top speed but would also raise the ride height and add more weight because of the larger tire. Using this equation I can find the same overall roll out for the 16" Snow hogs to lower my height and lessen the weight.

20 - 25 = 1.25:1
50" / 1.25 = 40.00 which is essentially the same as 40.04

Air pressure also plays a major part of the circumference of a tire.

I hope this can help some and good luck up north.

[skeeter]

The atv is a honda trx90 (2001) model !!! JUst wondering what to do with the rear or should I focus on the front sprocket ?? By the way the quad has an FMF pipe and I have cut the pink rev wire also has holeshot tires and itp wheels !!!

[Livin4Real]

Remeber to consider track conditions as well. If your on a short tight technical track (indoors) you don't need massive topend, you need more torque. Outdoors on a big track and long straights your going to need the topend more.