shoeys08dkcandygt

Got new tires last tues. Stock summer only p zeros lasted 14.5k miles. Went with hankook evo ventus k110. But went with 255/40/19 up front and 275/40/19 on the rear. When changing the revs per mile on my tuner. It's only one value no way to put revs per mile for front tires and a diff number for the rears. Do I just use the read tire number or do u average the 2 together? Thanks for any info u guys and gals with staggered setups use.

AzPete

Use the rear tire size. The front has nothing to do with the speed calculations.

shoeys08dkcandygt

That's what I thought and used. Thank you sir for the quick response.

siggyfreud

Just think about what actually gets connected via the driveline to the engine. On a FWD vehicle, the fronts are the only ones that determine engine RPM.

In this case it looks like your front and rear tires only differ in width, not height, and height will determine your RPMs. So even if you had entered front dimensions only, your gauge would still have been correct.

shoeys08dkcandygt

The 275/40 are 27'7 inches and the 255/40 are 27'. Tuner has 750 and 755 as values and the tires are 751 revs per mile. Last question is which number do I use? The higher 755 to make sure the abs isn't doing anything to slow me down or the 750 which is closer to the true revs per mile

Exley

I would put in 750, that way your speedometer is as close to correct as possible. I don't think that would cause any trouble with your ABS. ABS looks more for one wheel spinning faster or slower than the others.

Edit: just saw you have a 2012, they have stability control too and I'm not sure how that relates to the revs per mile

AzPete

It should not effect anything either way. There are very few times that all 4 wheels are turning at the identical speed. Any direction correction with the steering wheel and individual wheel speed varies.....and then there are the corners.

You are over thinking this process. Enter the closest number to the rear tires and go drive the thing.......

shoeys08dkcandygt

Thanks Pete. Just wanted to make sure I was getting things correct.

AzPete

I understand......sometimes we all fall into that "over thinking" stage.