Quote Originally Posted by Cam99 View Post
I'm going to piggy back on this thread. 93 t-5 and 26" diameter tires. What is the diameter of stock size wheels on 16" pony wheels . 26" also?
The 225/55/16 tire diameter will vary somewhat depending on manufacturer. It's safe to say it will be close to 26" though.

So we take the 26" tire height and multiply it by pi (3.1416) and arrive at circumference, that being 81.68". Then divide 63,360 (inches in one mile) by the circumference(81.68") to arrive at tire revolutions per mile. That value being 775.7 tire revolutions per mile.

Then use this formula to calculate speedometer *driven* gear needed.

Driven gear teeth= drive gear teeth x axle ratio x tire rev. per mile DIVIDED by 1000

8 x 3.73 x 775.7 DIVIDED by 1000=23.14

Looks like a 23 tooth speedometer gear would be the closest match.