Question for anyone running the sct tuner. When calibrating your tire size, it say you do it by revs per mile. When I search online, I keep getting different options. I've searched 1010 tires calculator as well as many others. And all of them are different. Bfg and other manufacturers do list revs per mile, so who do I go with in terms of changing the revs?

 

You will probably need some trial and error, anyway. Some people ended up with a revolutions number that seemed way off, but worked. So pick one and start there. Test speed with a phone app and adjust from there.

 

Some time ago, I contacted SCT. They said to use 1010 tires as they seemed to more accurate.
Try downloading and installing the forscan application and pick the right size.

 

I used 1010 tires, but there claim for a 285/70/17 is 635 revs, bfg websites day for that size is 395?

 

The best thing to do is get a tape measure and measure the rear tire from the concrete to the top, actual tire sizes vary by manufacturer and then only when brand new, as the tire wears that will change. Use the actual measurement to get the revs/mile and you should be spot on. Example I have BFG K02's in 35LT, actual measurement at the time of changing the r/m setting was something closer to 33.5". My speedo is dead on accurate with GPS.
.

 

Try setting it to as close to 638 revolutions as you can and then use a gps speedo app (waze navigation works really well) and see how close you are.

 

bfg has it at 635 revs/mile......

 

No normal tire for a truck will be 395, that's definitely off. If my math is correct, that's a 4.5' diameter tractor tire.