her ya go
rpm /336/grXtrX2==mph
gr=gear ratio
tr= tire radius from center of hub to ground
so, 2800 divided by336 divided 4.1 times tire raduis from hub to ground times 2
=54.88. the reason i say tire radius from the hub center to ground it the tire
radius is shorter from the hub to ground that from hub to top of tire. the
radius times 2 is much more acurate. you can reverse the formula to go the other
way as well. this is for stanard trans or lock up torque converters only. for
non lockup automatics use 356 instead of 336
new mexico jim
51 two ton dump
MLayton324@aol.com wrote:
> RPM = V / D x GR x 334.2
> Where:
> V = vehicle speed in mph
> D = effective tire diameter
> GR = gear ratio (e.g., for my truck, 4.10 rear x .70 overdrive = 2.87)
>
> the above formula on the chevy truck sit does not seem to work out what am
> i doing wrong
>
> 55 mph/ 27 inch tire is 2.03 2.03 x 4.10(gear ratio) x 334.2 equals 2781
> which is supposed to be rpms at 55
>
> if i was only turning 2800 at 55 i would be estatic i cant even get it to
> 55 without feeling like its gonna blow help??
>
> thanks mike layton
> 50 3100
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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