Garry, Thanks for the info. You've got my ears perked about not going over 55 for a while. As is - with my tube type 7.00 x 15's, my trucks sweet spot on the highway is 60mph. It will go 75 but gets quite loud at that speed. I believe the gear ratio on my posi is 3.89. Next year I will be adding an overdrive. Back to the wheel/ tire combo - what do you think the difference would be if I used 16s instead of 15s while keeping the outside diameter (28 1\2) the same? What negative/positive impacts would be made by increasing the diameter?
