Great deals on TJ parts on Amazon!

Looking for parts for your Jeep Wrangler TJ? Checkout the selection of TJ parts Amazon has to offer, many with 2-day Prime shipping!

Click the image below to browse TJ parts on Amazon.

Jeep Wrangler TJ Parts on Amazon

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

Are 31 inch tires good on the highway?

Ludogsonthemoon

New Member
Joined
Jan 10, 2022
Messages
10
Location
Philadelphia
I currently have P235/70R15 on my TJ and so far they have been great for highway driving and mild trails. I'm thinking about getting 31 inch tires once I save up enough cash and time. Will there be a big difference on the highway going from 28 inch to 31 inch tires?
 

Jerry Bransford

TJ Guru Moderator
Staff Member
Supporting Member
Joined
Nov 9, 2015
Messages
24,859
Location
Fleming Island Florida
31's are fine on the highway, that's the size tire the Rubicon with the 4.0 engine came with. You'll notice a slight loss in power with the larger diameter tire though, more so if your axles have the dreaded 3.07 ratio, less if they have the more desirable 3.73 ratio with the 4.0 engine. More of a power loss if you have the 2.5 engine. Your Profile is empty and doesn't give any information about your TJ like it's engine size, transmission type, etc., please fill it in when you can. :)
 

txbemis69

was last seen escaping the asylum
Supporting Member
Joined
Mar 2, 2020
Messages
447
Location
east texas
my jeep drove good with 31” tires. 4.0, 42rle @ 3.73 gears. 33” tires are a different story, needs a regear kinda bad.
 
  • Like
Reactions: Jim B

antwon412

TJ Enthusiast
Joined
Dec 26, 2020
Messages
149
Location
NorCal
I had 31s with the 3.07 gears. I instantly went from a five speed transmission to a four speed! 😄

They handle fine, they worked really well on most the trails I wanted. They even handled the trails really well in Moab.
 
  • Like
Reactions: tr21triton
OP
Ludogsonthemoon

Ludogsonthemoon

New Member
Joined
Jan 10, 2022
Messages
10
Location
Philadelphia
31's are fine on the highway, that's the size tire the Rubicon with the 4.0 engine came with. You'll notice a slight loss in power with the larger diameter tire though, more so if your axles have the dreaded 3.07 ratio, less if they have the more desirable 3.73 ratio with the 4.0 engine. More of a power loss if you have the 2.5 engine. Your Profile is empty and doesn't give any information about your TJ like it's engine size, transmission type, etc., please fill it in when you can. :)

Hi, thanks, I just updated my profile. I have a 1998 Sahara 4.0L with a 3 speed automatic transmission. As for the gear ratio I'm not 100 percent sure.

IMG_0320.jpg
I'll attach a photo .
 
  • Like
Reactions: Jerry Bransford
OP
Ludogsonthemoon

Ludogsonthemoon

New Member
Joined
Jan 10, 2022
Messages
10
Location
Philadelphia
Have 4.0, 5 speed, 3.73. Just went from 30" tires to 31". Did notice a slight loss of power especially in 5th. It's a daily driver and have no problems. But would take a free regear in a heartbeat if offered.

I wonder if I should just upgrade to 30" tires instead. I really like to be able to perform on the highway and was really surprised that I have no problems speeding up and passing. The thing cruises at 80mph with no issues.
 

03coloradowrangler

TJ Enthusiast
Supporting Member
Joined
Jun 25, 2019
Messages
947
Location
MI
Clean off this tag to figure out your ratio.
I do know you have a Dana 30 front axle and its hard to hard to tell.. but you may have a Dana 44 rear (y)
3BF53F32-7C39-4C45-93A4-F0B9E2C6C4B5_1_201_a.jpeg


This is my rear Dana 44 tag. 3.73 ratio as identified in the upper left. I am running 31's and have no complaints. I did notice a decrease in acceleration but not enough to complain about. biggest complaint is if I am driving in a strong head on wind while on the highway I do struggle in 5th gear and sometimes need to drop to 4th. otherwise I dont have any problems.
should also note, I am not running any lift at all with the 31" tires. just KO2's 31x10.5x15, seeing how at one point you were considering a lift. only a minor tire rub on tight turns where I hit the stops on the steering knuckles and during severe articulation on trails out west no tire contact to fenders.
53C9E30E-EE3F-4A95-BFA5-9C66362E8C69.jpeg
 
Last edited:
  • Love
Reactions: Jerry Bransford

SugarPops

New Member
Joined
Sep 26, 2018
Messages
9
Location
Baja
I wonder if I should just upgrade to 30" tires instead. I really like to be able to perform on the highway and was really surprised that I have no problems speeding up and passing. The thing cruises at 80mph with no issues.

31" are fine on the highway for me. I just noticed I have to downshift where didn't use to. Still prefer the 31" over 30" for looks if nothing else.
 

chudlet

TJ Enthusiast
Supporting Member
Joined
Apr 18, 2022
Messages
106
Location
N Idaho
Not trying to thread jack but 30's on 3:55s with 4.0. 5th gear still decent?

meh.. I have 31's on 3.75s and 5th is reserved for flat or downhill freeway. Hills and headwind you will want to drop to 4th to keep your RPM up.
 

TheBoogieman

Disturbed American
Supporting Member
Joined
Jan 1, 2019
Messages
6,746
Location
C-Ville VA
Yes, I had that combination on my 97 TJ when I bought it new.

Pics or it never happened to you too. I need to see JerryB with 30" tires on a Jeep. I don't believe it. ;)

p.s. It's ok if you're on the hill in Zorba's driveway in Fl. He went overboard to fix a winch he'll never have to use.
 
Last edited:
  • Like
Reactions: Zorba

Vtx531

TJ Addict
Joined
Nov 17, 2020
Messages
1,348
Location
Kalamazoo, MI
30" tires would be great. That's what came on your Jeep. No issues with gearing. No issues with steering rubbing. No issues with tailgate spare mounting. No issues with wheel offset and steering handling (Rubicon wheels have .25" more offset for 31s and they still kept the 9.50 width even on the Rubis).

Why not just go with 30's and have everything work the way it was designed?
 

machoheadgames

LED turn signal club
Supporting Member
Joined
Jan 21, 2021
Messages
1,129
Location
Dallas, TX
Not trying to thread jack but 30's on 3:55s with 4.0. 5th gear still decent?

31s and 3.55 (5-speed) sucked when I ran it. I’m sure 30’s are not a lot better. 5th was definitely flat or downhill only for me.

Was around 2100 or so at 70.