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NHWK05 09-26-2011 08:21 AM

Tire size recalibration
I am hoping to get new tires before winter, (if i can manage to keep up with my payments that is). I had 265/65/17s before and though they are only about 1" taller and wider then stock i did notice a difference in the speedo and the EVIC MPGs. My MPGs dropped by about 1.5 miles per gallon or more.

Lately ive been getting much better gas mileage with stock 245/65/17s on my jeep. I dont want to ruin a good thing by putting bigger tires on it unless i there is a way to re calibrate everything so that the speedo and MPGS are accurate. I dont think this tire size change would honestly cost me 1 to 2 miles per gallon on a 05 4.7 V8.

I also use fuelly to keep track of my mileage but that was hard to do since everything was off so were the miles driven.

Is there anything i can do? Super chips tune? Anything cheaper then a tune?

If not i am just going to keep the stock size 245s.

SvenskaJeepGuy 09-26-2011 12:13 PM

Re: Tire size recalibration
Doesnt your tire shop do it?

NHWK05 09-26-2011 03:18 PM

Re: Tire size recalibration
Tire shops can't recalibrate for change in tire size or speedo calibration.

jlewissystem 09-26-2011 03:29 PM

Re: Tire size recalibration
I've only heard that the dealer can take you to stock - 31.5, but to get past that - i think you'll need a tuner.

Mr. Boh 09-26-2011 03:39 PM

Re: Tire size recalibration
Yep, dealer can only do stock WK tire sizes. Hypertech and the like can correct your speedo for any tire size.

misfit77 09-26-2011 03:55 PM

Re: Tire size recalibration
I learned the hardway....they can calibrate. Only change the tire size which is no larger than stock. The service Manager had no clue about tire sizes. Sad!

I had to get a calibrater from Hypertech.

Youre in luck you can get a powerprogrammer from Hypertech...that means you can gain a few HP.

NHWK05 09-27-2011 07:28 AM

Re: Tire size recalibration
Thanks guys. I am in no position to buy a tuner and if anything I am more concerned about gas mileage then HP. I loved how my jeep looked with the 265s but everything was off because of it so I could not have accurate info for gas mileage or speed miles driven.

I will most likely just buy the stock size again. I am starting to think more conservativly.

I also need to go through it and make sure all the tune up stuff is done. There are a lot of other people with gen 1 4.7 v8s getting much better mpgs then I am.

robpp 09-27-2011 09:51 AM

Re: Tire size recalibration
walking would net you the BEST gas mileage.

also any tire larger or more rolling mass will decrease your gas mileage.

NHWK05 09-27-2011 10:07 AM

Re: Tire size recalibration
Thanks smart ass:p I know that much. My point was if iknow that the speedo, and miles are forrect then I can more accuratly judge my gas mileage. The revolutions per mile are only different but a few revs. My issue was last time I had larger tires I could not get any accurate readings so my mileage was off. I don't think the mpgs changed by very much at all in reality just in the evic. So if I did go larger and could easily reset everything then ill at least know my speed distance and mpgs are correct.

I don't honestly think that a one inch taller one inch wider 5lb heavier tire should really make that big of a difference in gas mileage.

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