Axle Ratio/Tire Size Calculator -
Version 1.1 Created by Mark Medina at 4lo.com
Updated: October 2, 1997
Here are a few calculators that may be useful in deciding tire size and gear
ratios .
Ever wonder how far off
your speedometer is with your new bigger tires? I'm using a simple ratio
calculation, so this info will only approximate your corrected speed and depends
on the accuracy of tire size diameters (assuming nothing but tire size has
changed).
Now that you have your
truck lifted, you want bigger meats. They look cool and have the potential of
being very functional, but they may also be robbing you of power/gas mileage.
This calculator will get you back to a ratio that's closer to your original.
Enter the values on the left and press Compute.
Ever wonder what your
low-low-low gear ratio is, your "crawl ratio"? You'll need to do a
little research by finding out the transfer case and transmission ratios first.
Enter your values on the left side, press Compute and your answer will be on the
right.
Find
Overall Crawl Ratio
Trans.
Ratio: T-Case
Ratio: Axle Ratio:
Overall
Ratio:
I've spend a bunch of
time trying to WAG (wild ass guess) my actual MPH when going down the road. By
knowing your gear ratios and tire size you'll get a more accurate idea here.
Enter the value on the left, press Compute.
I suppose if you don't
have a tachometer you could use this form, otherwise it's only useful to find
out how accurate your Tach is. Enter the values on the left, press Compute.
This formula is a nice
way to get the tire diameter of those metric tires that are common on just about
everything stock. For example a 265/75R16 would be around 31.6 inches tall.
Enter the numbers into this form in the order you read them from the tire and
press Compute.