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Author Topic:   mph
Dirt Freak

Total posts: 306
posted August 02, 2003 12:14 AM  
i know theres a formula that i can use to determin top speed i've try'ed the one in the tool box but i think its for a 1 to 1 trans ratio does any one know how it would work for an overdrive with .73to 1 ratio
that would include rpm,trans,rear gearing and tire get a better idea.
thanks for any help

Dirt Forum Champ
Total posts: 730
posted August 02, 2003 08:45 AM  
the one in the tool box will work for ya. take overdrive gear ratio times rear end ratio to get your final drive ratio, put that figure in where it says gear ratio and it should work. heres an example. i run 1st gear with a t-350 (2.52) a rear gear is a 2.75. 2.52 X 2.75 = 6.93. 13" tire radius and 6500 rpm = 72.58 mph hope that helps.

Drive it in deep, and come out hard!!

Earl Parker II
Dirt Full Roller

Total posts: 69
posted August 02, 2003 10:09 AM  
You might want to go to and download the 'RPM, MPH, Tire Diameter and Final Drive Ratio v. 1.0' calculator- it will make these types of calculations easy.

Earl Parker II

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