Tuner tire size adjustment Q

[usaf2006]

I currently have 265/70R17 tires on my truck right now. They measure out to 30.5" at proper tire pressure. Would you guys set the tire size with your tuner to 30" or 31"?

 

[justin13703]

I'd do 31 to have your speedo read a little fast if anything. I don't like it reading lower than your real speed because of tickets and such. But you won't notice hardly anything from 1/2 inch difference. I never got mine adjusted after I got my 35s and my speedo is only off by 2-3 mph at 70.

 

[usaf2006]

Gotcha. I just wanted to be able to calc my mpg as best as possible, not that it really matters though. Thanks!

 

[ST-8]

Can't you adjust it per 1/4in?

 

[LifeSTRONG]

Can't you adjust it per 1/4in?

Yes

 

[ST-8]

So why don't you do that?

 

[usaf2006]

IIRC, when I was doing mine it was going up and down per inch, not 1/4 inch. Maybe somehow I overlooked that lol.

 

[brandonjansen]

Adjust it to what you think is correct, then download a GPS speedometer to your phone and check it with that. Lots of tuners don't actually make the speedometer 100% correct if you enter the exact tire size in. For some reason they can be way out. For example with my H&S MiniMaxx I have the tire size set somewhere around 35.7" (IIRC) running 37" tires and that get's it as close to correct as I can.

 

[usaf2006]

Good to know! Thanks folks.