tire size with 2.5" lift question


GusGus

New Member
Supporting Member
Joined
Jun 6, 2020
Messages
5
Location
Ohio
Just got a flat and it's time for new tires. Currently running 265/70R17's on a 2015 JK with a 2.5" Rough Country lift and quick disconnects. This tires look so small in the wheel wells. How much larger can I go without issues?
 

Anybodyhome

USN Retired (1973-1993)
Supporting Member
Joined
Jun 15, 2020
Messages
501
Location
Nashville, NC
You can squeeze a set of 37s under the fenders.
I have a 2.5" lift with 35 x 12.5 x 18:

Jeep 4.jpg
 
  • Like
Reactions: mrjp and GusGus

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
1,782
Location
Huntington In
Just got a flat and it's time for new tires. Currently running 265/70R17's on a 2015 JK with a 2.5" Rough Country lift and quick disconnects. This tires look so small in the wheel wells. How much larger can I go without issues?


If it's a daily driver with occasional trails you can do a 35", but might also have to do a gear change depending on what gears you have.
 

MacGuyver

JK Enthusiast
Joined
May 13, 2020
Messages
360
Location
Wisconsin
Are your wheels stock? You are about at the max size for the 17 x 7.5s that jeeps come with. Just not enough backspacing, meaning wider tires will rub on frame / suspension components. This nothing to do with a lift kit.
 
  • Like
Reactions: mrjp

badeye

New Member
Joined
May 5, 2021
Messages
4
Location
Chattanooga, TN
If you go with aftermarket wheels with 3 1/2" back spacing 35's fit great. But you will have to change your gears. People will tell you that they are running 35's without a gear swap, but I guarantee they have problems on hills and keeping up at highway speeds. 4.56 gears worked perfectly for my manual transmission.
 
  • Like
Reactions: mrjp

MacGuyver

JK Enthusiast
Joined
May 13, 2020
Messages
360
Location
Wisconsin
Here is my 2009 with a 2.5 teraflex lift. The wheels are pro-comp 17 x 9 and the tires are 285 x 70 x 17, which is as size that is considered a 33". It's a manual with rubicon gearing so I could probably go up to a 35, but I haven't had a reason to.

These tires did not fit on stock wheels... I tried. Thankfully I'm friends with my tire guy. Ordered the wheels and had him put them on a few days later.

Spacers are an option some will bring up, however I would strongly urge you not to. They are a mechanical failure point and many shops won't even work on a vehicle with them on. I'm guessing if you don't tell your insurance and they fail, that is your bill to pay all my your lonesome.

Also, post a pic. Welcome to the gang.
l2WdgAV5qU-0nnKYYx0-yMkj=w1410-h1057-no?authuser=0.jpg
 
Last edited:
  • Like
Reactions: mrjp

JerryD

¯\_(ツ)_/¯
Supporting Member
Joined
Dec 20, 2019
Messages
372
Location
West Michigan
If you go with aftermarket wheels with 3 1/2" back spacing 35's fit great. But you will have to change your gears. People will tell you that they are running 35's without a gear swap, but I guarantee they have problems on hills and keeping up at highway speeds. 4.56 gears worked perfectly for my manual transmission.
Regearing is a good idea, almost mandatory. BUT... it depends on the terrain. In Tennessee, yeah I can see it being a royal pain, but Michigan is mostly flat-ish, especially along I-75. I have 35's, 3.73 gears and can run 80 on the highway no problem. The 3.6 makes a big difference, too. That said, 4.56's are in my future (I'll never go larger than 35's).

Also, if you have the D30 up front, anything larger than 35's will likely require some beefier components up front eventually, too.
 
  • Like
Reactions: mrjp

15' JK 4 Me

Member
Joined
Apr 26, 2020
Messages
58
Location
Cape Coral FL
Regearing is a good idea, almost mandatory. BUT... it depends on the terrain. In Tennessee, yeah I can see it being a royal pain, but Michigan is mostly flat-ish, especially along I-75. I have 35's, 3.73 gears and can run 80 on the highway no problem. The 3.6 makes a big difference, too. That said, 4.56's are in my future (I'll never go larger than 35's).

Also, if you have the D30 up front, anything larger than 35's will likely require some beefier components up front eventually, too.
I'd be curious what your RPM's are at 80. I recently went to 35's with stock 3.21 gears. I'm in Florida, completely flat. I haven't done highway speeds yet, most is 60 going to/from work. I can feel the difference with the 35's. I can probably stay with them but do plan on 4.56 change out after I pay my taxes. I don't remember my RPM's at 60 but know it doesn't go into 5th (automatic) until I hit 50-55. :)
 
  • Like
Reactions: mrjp

JerryD

¯\_(ツ)_/¯
Supporting Member
Joined
Dec 20, 2019
Messages
372
Location
West Michigan
I'd be curious what your RPM's are at 80. I recently went to 35's with stock 3.21 gears. I'm in Florida, completely flat. I haven't done highway speeds yet, most is 60 going to/from work. I can feel the difference with the 35's. I can probably stay with them but do plan on 4.56 change out after I pay my taxes. I don't remember my RPM's at 60 but know it doesn't go into 5th (automatic) until I hit 50-55. :)
Well, truth be told, I don't like going 80 in the Jeep - usually it's when I'm keeping up with traffic and then I'll let it go back to 73-75 when the limit is 75. I can't recall the ACTUAL tire size of my 35's but assuming they are for the sake of argument, and using an online calculator, I'm turning ~2865 at 80mph. Same conditions but with 3.21 gears and I'd be at 2465. With 4.56 gears, it would be a shade over 3500.

I do manually downshift at times and it's so automatic now (no pun intended), I don't think about it much. Re-gearing would eliminate that.
 
  • Like
Reactions: mrjp

BLACKJKU

Moderator
Staff Member
Lifetime Supporting Member
Joined
Feb 22, 2020
Messages
1,782
Location
Huntington In
I'd be curious what your RPM's are at 80. I recently went to 35's with stock 3.21 gears. I'm in Florida, completely flat. I haven't done highway speeds yet, most is 60 going to/from work. I can feel the difference with the 35's. I can probably stay with them but do plan on 4.56 change out after I pay my taxes. I don't remember my RPM's at 60 but know it doesn't go into 5th (automatic) until I hit 50-55. :)

When I bought my JK it had 35's and I have a manual trans with 3.21 gears and hated it. I put the stock sized tires back on it and it's much better. It's hard on the gears and clutch with 3.21's and 35's if you doing anything more then driving on level roads.
 
  • Like
Reactions: mrjp and JerryD

IndominusHuman

JK Enthusiast
Joined
Oct 20, 2019
Messages
489
Location
Conway, AR
I'd be curious what your RPM's are at 80. I recently went to 35's with stock 3.21 gears. I'm in Florida, completely flat. I haven't done highway speeds yet, most is 60 going to/from work. I can feel the difference with the 35's. I can probably stay with them but do plan on 4.56 change out after I pay my taxes. I don't remember my RPM's at 60 but know it doesn't go into 5th (automatic) until I hit 50-55. :)
I have a automatic, but 35s with 4.10 gears I run about 2500 RPM on the highway at 75/80.

I have zero issues. I prefer getting over 2mpg on the highway :ROFLMAO:
 
  • Like
Reactions: Daddyo2373 and mrjp

TRAUMAhead

New Member
Joined
May 8, 2021
Messages
4
Location
Bakersfield, CA
You can fit 37s with wheels with 4.5" backspacing and bump stops adjusted accordingly at a minimum.

First photo is 35s, stock cut fenders. Second and third photo is 37s, GenRight fender delete kit. MetalCloak 2.5" coils with 1" spacer up front to level it out. I'm running 5.38 gears, but I have a 2010 with the 3.8L.

51166049597_fbf404982d_h.jpg


42570331474_57d91e52a3_h.jpg


51166746291_135b648440_h.jpg
 
Last edited:
  • Like
Reactions: mrjp

Daddyo2373

Member
Ride of the Month Winner
Joined
Jan 2, 2020
Messages
92
Location
Greenville, SC
We have a 2010 Rubicon and are running 315/70 on stock 17 rims. Had to use spacers but has been this way for several years with no issues. I wouldn't go any bigger than 35 though.
Could it use a regear......yes it would help but it does pretty good as it is. Not a need at the moment.

20200314_133352.jpg
 
  • Like
Reactions: mrjp