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Discussion Starter #1
Hi All-
I'm new to this forum and just got a 2015 Wrangler Sahara 2-door.

I wanted to see if there would be any problems upsizing my OEM tires from:
255/70/18 Bridgestone tires to 275/70/18 Goodrich A/T T/A KO2 (or similar) tires? **

OEM tire specs are:
7.5" Tread; 32.1" Tall; 6.5-8.5" Rim width range

New tire specs are:
9.0" Tread; 33.2" Tall; 7-8.5" Rim width range.

The new tire is about 1" taller and it looks like there is plenty of fender clearance.
I'm not planning to lift the Jeep and keeping it stock height.

Any issues that could be expected from this change, computer, traction control, etc, or that may affect the warranty?

Thank you in advance, and sorry if this was posted before.


** My 2nd choice for aftermarket tires are: Firestone Destination M/T, since BF Goodrich doesn't make the M/T in the 275/70/18" size.

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rubbing should not be an issue, but you will need to recalibrate your ECU.. The dealer could do this for you if you dont mind dealing (and paying) them..Or you can get an AEV ProCal (or similar) device and do it yourself.
 

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Discussion Starter #3
So if I understand correctly, the dealer can do that ECU recalibration, no problem?
How about the tire width getting about 1.5" wider... any issues with doing that?

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The dealer can do it, yes.. "No problem"? probably not.. They will probably charge you an hour or two of labor, after telling you it's not necessary and/or not possible.. of course then you'll have to schedule when to bring it in.. leave it there for a day or two (even though the process only takes a few minutes) .. you'll probably have to rent a car..blah blah.. Call your dealer to get a feel for the level of 'problem' ..

The only potential problem with the width would be potential rubbing on the fenders when offroading if/when at full turn and full flex. Probably not even an issue with that sized tire - but i'll leave it up to someone that knows better than me to do the math..
 

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Discussion Starter #5
UPDATE

I decided to downsize my 18" Sahara rims and go with 17" rims instead. There are way more
tire size choices available with the 17" size.

The new 285/70/17 Tires are .6" taller than the OEM tires (255/70/18).

They worked out nicely, no rubbing, no issues.


Do I need to re-calibrate for the .6" taller difference, or is this something not worth the bother ??

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UPDATE I decided to downsize my 18" Sahara rims and go with 17" rims instead. There are way more tire size choices available with the 17" size. The new 285/70/17 Tires are .6" taller than the OEM tires (255/70/18). They worked out nicely, no rubbing, no issues. Do I need to re-calibrate for the .6" taller difference, or is this something not worth the bother ?? .
If you are driving an automatic, you definitely need to recalibrate. All your shift points will be out of whack if not.

Good to hear you didn't have any rubbing. When I went to 285/70/17 BFG KO2s, I had a bad rub on the sway at full lock right turn.
 

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If you are driving an automatic, you definitely need to recalibrate. All your shift points will be out of whack if not. Good to hear you didn't have any rubbing. When I went to 285/70/17 BFG KO2s, I had a bad rub on the sway at full lock right turn.
I went from stock 255/75/17 to 285/70/17 on my 2015 JKUR and my auto shifting was all f'd up for a while. I think my jeep learned to shift better though. I did order Procal and waiting for delivery. Will recalibrate.
 

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UPDATE I decided to downsize my 18" Sahara rims and go with 17" rims instead. There are way more tire size choices available with the 17" size. The new 285/70/17 Tires are .6" taller than the OEM tires (255/70/18). They worked out nicely, no rubbing, no issues. Do I need to re-calibrate for the .6" taller difference, or is this something not worth the bother ?? .
spend the $150.00 on an AEV procal or Flashcal. It'll make you very happy. It did me very recently. Good luck.
 

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Discussion Starter #9
The AEV Procal seems like a good idea. Also seems like a one-time use for many.

Anyone want to sell a used AEV Procal?
 

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YES! spend the money and get the flashcal. I just bought the $150 and calibrated my speedo after installing 34" tires. As far as your sport handling a tire upgrade you have 3.21 gearing. I have 3.73 gearing in my willy's 2015. I didnt notice a bit of difference after the install. but you prob will. I don't think it would be so bad that you couldn't drive it but you may want to think about re-gearing to 4:10 or 4:56. I had to set my tires in the cal to 33" to get my speedo to be correct. I did this using my GPS nav: comparing my speedo.
 
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