Attachment 10980

I've been looking at the effective ratios of different tire sizes versus the axle ratios. Here is a snapshot of an exel spreadsheet where I can plug in different tire sizes and speeds and get the RPMs - this one ist at 65 MPH. If the tires are the same size, the 3.55 is 10.6% lower and the 3.92 is 22.1% lower than the 3.21. So a truck with 3.55 and 33" tires is "effectively" only 3.9% lower than a 3.21 with 31"s. If one keeps looking at the char, a 3.92 with 35"s is only 8.2% lower than the 3.21 with 31"s. That is why we get so many different real life opinions on how the trucks do towing and driving if we only look at the gear ratios.
The tire sizes are on the left