hey do you know the formula where you plug in your rpm, tranny gear ratio, mph, and tire diameter to find your rear end ratio?

I know you can find it in the equations page, but I need the actual #s you plug in.

 

The numbers:

For mph, look at your speedo (or better yet, time yourself on a measured stretch of road)
For RPM, look at your tach (which if it's a factory one is probably wrong, specifically too high)
For tire size, use a ruler
For gear ratio, use 4th gear if it's a T-5 or D not OD if it's a 700, and that's 1:1

Sorry, I can't tell you what your particular numbers will all be.

 

the equation isn't too difficult to figure out if you think about it.

first, you need your tire diameter, then multiply that by pi.

that gives you the distance your car travels in inchs. with one revolution of the wheel. then divide that by 12 to get the distance in feet. then divide by 5280 to get it in miles.

using the transmission gear of 1:1, and a rear end gear of say 3.23:1, your driveshaft turns 3.23 times for every rotation of the wheels.

so we multiply the RPM by 60 to get revolutions per hour, or RPH

divide the RPH by the gear ratio(trasmission gear*rear axle ratio)
to get the amount of revolutions of the wheel per hour

take that and multiply it by the circufrence of the wheel in miles.

so

RPM*60/rear end ratio*tire diameter*pi/12/5280 = mph

or simplified.

RPM/rear end gear*tire diameter*0.002975 = MPH

 

I know you told me I could quit, but I got it:

Final Gear Ratio=(RPM)(60)(Tire Diameter)(Pi)/(Tranny Ratio)(63360)(MPH)

Boo Yow!

-Corey