Seeking Gear Ratio Info From the guys running large lug tracks

[LoudHandle]

I'm curious what is everyone running as far as ratio and driver for those turning the 2.5" and 3" lug height tracks. Who is running a 9T driver in either the 2.89" or the 3" Pitch and what gear ratio are you running? What actual track speed are you achieving? I really don't care what brand it is, Just what driver and chain case gear ratio you are running, engine HP and Torque would be helpful but not required.

Working on a prototype drive and just would like to start in the ballpark to save development funds for further R&D.

Thanks for your Input.

 

[wardy]

2.86 8 tooth drivers 21/45 2.14 ratio, camo extreme
2.5 x 15 x 150
Track speed is 48 to 50
Gonna try 43 gear to load the motor little more

 

[Scott]

2.52 pitch
10t drivers
19/43 gears

That's a gear ratio of 2.08

159"x2.25" finger track.

8500rpms.

Got a new secondary clutch, so I don't know my track speed.........yet.

 

[glassman]

19/46 gearing, 162 x 3" x 3.0 pitch, 9 tooth drivers, 39 - 40 mph track speed on heavy powder runs. Polaris 800 pro.

 

[4Z]

The tallest ratio I have had luck with on the 2.5 x 162 is around 2.15 - 2.20 ish with 8 tooth drivers. Saw 45+ mph when clutched correctly.

This season went with a 3" and a 2.17 ratio, IMO right on the limit for my sled for WA Cascade cement snow, but insanely awesome on the "dry days" we have had.

Ported, twin pipe, 14:1 comp, 800

 

[whittaker727]

So how do I figure my ratio? Going 7 tooth drivers 19/43 163 X2 1/2" track shooting for 8300 rpm.

 

[LoudHandle]

So how do I figure my ratio? Going 7 tooth drivers 19/43 163 X2 1/2" track shooting for 8300 rpm.

Your actual gear ratio is 43/19 or 2.263
Of course your driver (Teeth and Pitch) play a big role in how the chaincase ratio relates to track speed as follows.
For estimating theoretical track speed:
Engine RPM / gear ratio = driver RPM
Driver RPM x Teeth x Pitch ( in Inches) x 60 (to get Minutes to Hours) / 12 (to convert Inches to Feet) / 5280 ( to convert feet to Miles) = MPH ( this assumes your clutches at full shift are a 1:1 ratio, some go past to a slight overdrive)
So your sled currently should be able to pull a track speed of 70.263 MPH

8300 / 2.263 x 7 x 2.89 x 60 / 12 / 5280 = 70.263