Does this sound right?

[DunesRunner08]

So I am messing with my SCT Tuner.... and I get to where I have to adjust my speedometer and it goes by rev's per mile and I Running a 40x15.50R22 Toyo Open Country M/T and i was trying to figure out all the numbers and I came up with the truck did 658.2 on the stock tires and with the 40's it is doing 524.1.... does this sound correct?

[GM Duraturd]

I got 504.025 revolutions per mile with the 40's. I may be wrong.

40 x 3.1427 (tire circumference in inches) = 125.708
5280 (feet in mile) x 12 = 63360 (inches in mile)
63360 / 125.708 = 504.025 rev/mile.

Make sense or am I missing something?

[DunesRunner08]

yeah but try the equation with the actual tire size from toyo's website.... 39.7

[DunesRunner08]

with that equation I got 508.1

[topdwg]

This is where I go to calculate my revs per mile: Tire size calculator

It works with the metric system. If you have your tire size in the standard system, just figure the metric values first with this calculator and then go on to determine your revolutions per mile with the above calculator.

Metric Tire Conversion Calculator - Red Rock 4x4

[topdwg]

I did it for you...

504...

[DBM]

most tire sites have the revs per mile on the page with their tire specs...Toyo lists that tire as 522 revs per mile

[DunesRunner08]

well then.... I am just going to plug in what Toyo says then... do you have a link to that page on their website?

[DBM]

here you go... http://toyotires.com/tires/suv-and-truck/full/OPMT/96

[DunesRunner08]

Thank you... I had the choice between 520 or 525 so I picked 520... hopefully my speedo will be correct....

for anyone with huge tires... this thing will adjust up to 46" or 48" I'd have to do the math, i highly suggest the SCT Livewire to anyone for its options and adjustability