Confused about tires

Hey everyone,

I'm confused about my tires purchase and have a few days that I can still take them back so I'm looking for your suggestions and hope you can help! I am a beginner at this and want your expert advice. I have a 2010 JKU Sahara with 3:73 gears (stock). I've installed the Bushwacker Flat Fender Flares and Fab Fours Front / Rear Bumpers. This is my daily driver and I put about 30,000 kms (18,000 miles) on it each year. I do a bit of wheeling but nothing extreme.

Here's where I'm at...

I purchased 17" Fuel Hostage 8.5" Rims and wrapped them in a gently used set of 35 x 12.50 Fierce Attitude M/T tires. I've always wanted 35's for the look but am regretting it for the fuel mileage. I'm getting about 30% worse fuel mileage now and don't like it. I really don't want to re-gear due to the cost but don't want puny looking tires with the mods I've done (the stock ones looked terrible). I'd also like to keep stock height for now - the shop I got it done at assured me it wasn't rubbing but it is over decent size bumps in the road.

If I drop to 33 x 12.50 will I see any improvement?

I know these questions are very basic for you guys but I need help!

Oh... I did buy the AEV Procal like Wayalife recommended me to in a past message - it helped a bit but I find that the Jeep is still revving high on the highway (it won't kick into overdrive - likes to stay around 3,000rpm at 70mph.

Hope to hear from you soon and thanks in advance for your suggestions!

Did you recalibrate your speedometer due to the bigger tires. Your fuel mileage computer will be off.

Jkzinger said:

Did you recalibrate your speedometer due to the bigger tires. Your fuel mileage computer will be off.

Click to expand...

LOL!! That's exactly what I was about to ask :yup:

I did. I recalibrated it with the AEV Procal Module and changed the pressure sensors. I drove it 40 miles today at 65 mph and rather than relying on what the computer said I fuelled up before and after the trip - still only got 12.9 mpg. It seems like the tranny doesn't want to shift into overdrive.

Do think this may be a gearing issue?

If you're in Cali, I'll trade you my 33's for your 35's!

That worries me a litt bit since I have a 2010 with the 3.73's as well and also plan on running 35's. Would the superchip traildash do more than the procal?

I hated my 35s with 4.10 gears, so yes, gears would help you out in the power department. I did still lose about 3 mpg when I went from my rubi tires to 35s. Lost another 2mpg going to 37s.

Thanks for everyone's help! I ended up taking the 35's back and went with Dick Cepek 33's. The fuel economy improved right away. Sad to see the 35's go but happy with my decision.

Sorry newtdog - I wish I was in Cali and not here in Canada - not only could we swap tires but there would also be no snow on the ground!