Tire sizes & rpm
 

Anyone know if I'd drop any significant amount of rpm if I changed from 24.5 low pros to 11R24.5 tires? Right now, I turn 1600 at highway speed out west and would like to drop that as much as possible.

probably about 60 rpms.

hmm. not as much as I thought. Thanks Allan.

The rolling resistance is higher on the taller rubber, right?

I guess 60 rpm wouldn't make any notable difference in the fuel mileage anyway.

Re: Tire sizes & rpm
 

Go to Bridgestones website www.trucktires.com , it has a Q&A section that will help you with any question you might have. It is in "Ask the Tire Doctor" questions answered section.

Thanks, Bee.

you should look at the revs per mile of the new tire. the formula is; revs per mile times axle ratio times top gear ratio equals engine RPM at 60 mph. for example,

495 revs per mile X 3.73 X 0.73 = 1347 rpm

another useful formula is:

new tire diameter divided by old tire diameter is how much your RPM will change.

example: your current tire is 42 in; you switch to 40.7 in

42/40.7 = 1.0319; so your RPM at a given speed will increase by 1.0319