what size sproket

[TheFontMaster]

Ok I have a 13 tooth front sproket, what size would be the best to get for the rear. I plan on riding trals and motocross, I'm looking to get around 80 mph out of it.

[speedjunkie250]

i think the 32 would be a good choice . i ran that on my r in mx idid good . it also dependz on the tire size your runnin for speed.

[XANDADA]

a 32?:confused:
I've tried a couple of different combos and always go back to 13/39 but that won't get you 80mph or even close. keep in mind rear tire size and engine performance will play a factor too in what works best for your quad. I'm runnin 20"rears and do mainly xc riding...

[xlr810]

I run 13/38 on an 86 tranny (faster 5 & 6) It runs to the low 70s on hardpack. That is with 20" rear tires. Going up to 22 rears on that gearing, or 14T front pushes it to around 80, but gear spacing seems off a tad, and have to stay in the powerband to hold 6th on mine. Ice is the only chance I ever have to get up to that kind of speed lately. I prefer more technical terrain.

[350rpowervalve]

For trail try 14/37 to have a lot of speed....I have 14/37 for drag with 350 pv ...

[ground_zero298]

I run 13/38 with 22's I get 75-76 out of it. For trail ridding I feel it's geared alittlte to high, we ride a bunch of really tight trails though. you can't have the best of both worlds.

I checked the calculator at 8250rpm with 13/36 and 20" tires you should get almost 76.

At 8250rpm with 14/36 and 20" tires you would get 81.
Don't know how this would run in trails though.

this is with stock tranny ratio.

[LT250Racer609]

i race mx and i usually ran a 13/39 depending one track sizes....

12/39 for supercross tracks
13/39 for motocross
14/39 for large motocross tracks

this is with 18" tires tho

[hang1p]

hey ground zero whats that formula to figure out the speed i seen it before but forgot it

[ground_zero298]

250r converter (http://home.earthlink.net/~gellett/250r.htm)

[punker69q]

I run 14/38 for mx (my track is fast and the quad pull it just fine), with 18 in rear tire I top out a about 77-78 mph, but that's with the engine screaming in 6th gear (i got a 86 bottom end with the tallest 6th gear). With 20in tires I could do about 85-86.

[hang1p]

bump

[250R-Dee]

I will be running a 13/37 with 20" tires on a Krank It Nationals P&P CT 310 after the rest of my small parts arrive. Oh yeah, I'm using an '86 tranny.