Recommended tire size for 4 cylinder engine?

[mushdogs]

I’m running 31’s with 4.10 and 2.5” suspension lift. This is my DD. Beyond 31 and the normally bad Jeep MPG is horribly abysmal; highway performance is non existent.
31 is a compromise of what I need for winter travel, summer overlanding, fall hunting and daily driving in the mountains and on the highway without breaking the bank come fill up time. I don’t have any issues not being able to use 5th at highway speeds.
Can I do 70 on the interstate? Yes.
Can I do 60 over a mountain pass highway? Depends on the grade.
Do I ever wish for two more cylinders? Only occasionally.
I for sure and certain wouldn’t run 31’s with 3.73 gears and expect to have the same results I have now.

 

[Fishtaco]

235-75R15 is real doable with out a lift, and ok offroad.
Of course it all depends what you are trying to achieve and how much money you want to spend to do it.
This can be easy, or you can go down the rabbit hole and before long, if the check book holds out, you
can be running 2.5 ton Rockwells, 48" Terra tires, and a 634" big block Chevy with a 8-71 blower
Seriously, since your at low elevation you likely could go with a MAX. of 31" tire with 2-2.5" lift.
Have fun with your Jeep!

OK I have 235x75R15 Wranglers on my 65th and I thought they were factory size but wider?

 

[Fishtaco]

OK I have 235x75R15 Wranglers on my 65th and I thought they were factory size but wider?

Nobody? lol 235x7515 are just wider stocks and not even close to 31s?

 

[Rubicon88]

Nobody? lol 235x7515 are just wider stocks and not even close to 31s?

Most 4 cylinders came with
215 75 15
Which are just shy of 29" tall

Comparing...
A 235 75 15 is one inch taller just shy of 29" and 3/4" wider around 9.25

Then there is 30x9.50x15 which is self explanatory.

Then 31/10.50x15 ...again self explanatory.

 

[Goatman]

Realistically the driver is every bit as important as the Jeep. You can run 40" tires with a turbine engine out of a Apache helicopter, but if you don't know where to put a tire you can still get stuck.
If bigger tires are not an option then try adding a locking diff to the rear (or front too) and then you will realize how much easier it is in rock strewn environments.
I have never (but once) owned an 8 cylinder engine. I've always been able to go anywhere I wanted with a straight 6. (Dislike a V6 for some reason) I wasn't always the first to the finish, but I was normally stuck helping someone with a broken axle from an overpowered engine. We used to haul 2 cows to the slaughterhouse over an hour away through back roads and 4 lane highways with an old 51 (?) DODGE 1 1/4 flatbed truck that had some tiny straight 6 engine. So old it had an oil bath air cleaner. Used it to haul cows since my grandfather got it (3 days from) new. Always got us there. So if you have to use a 4 cyl (by the way, that's the better 4 cyl.) then learn how to drive it to it's best ability and you will be fine. And from what I've heard about Greek roads, you will be waiting in a traffic jam most of the time.

 

[ColoJeep]

When you do the math the tire sizes are as follows :

215-75-15 = 8.46" wide X 27.69" tall

235-75-15 = 9.25" wide X 28.87" tall

And my pet peeve tire size that some folks refer to as " The metric equivalent 10.50 X 31"

245-75-15 = 9.64" wide X 29.58" tall.

 

[ColoJeep]

OOPS!
245-75-16 =9.64" wide X 30 46" tall

 

[Jerry Bransford]

For those with the $$$ to regear, there are many 4-bangers successfuly running 33" tires with 4.88 gearing. With 5.13 now being available I'd certainly consider a 33"/5.13 combination as very doable. The Dana 35 is ok with 33's but if you also want a rear locker it's time to also install a Super 35 kit from Revolution Gear. That beefs the rear axle shafts up to 30 spline 1541H which is more than up to that combination.

 

[Fishtaco]

OOPS!
245-75-16 =9.64" wide X 30 46" tall

When you do the math the tire sizes are as follows :

215-75-15 = 8.46" wide X 27.69" tall

235-75-15 = 9.25" wide X 28.87" tall

And my pet peeve tire size that some folks refer to as " The metric equivalent 10.50 X 31"

245-75-15 = 9.64" wide X 29.58" tall.

So what is the widest tire I can go on a stock 15 without spacers.

 

[ColoJeep]

"So what is the widest tire I can go on a stock 15 without spacers."

Fishtaco- on stock SE 4 banger wheels 235mm tires fit well without spacers.

Perhaps others can weigh in with other opinions and experiences.
But, you are going to be limited going to a very wide tire on a 6" wide rim,
regardless of any wheel spacers.

 

[Fishtaco]

"So what is the widest tire I can go on a stock 15 without spacers."

Fishtaco- on stock SE 4 banger wheels 235mm tires fit well without spacers.

Perhaps others can weigh in with other opinions and experiences.
But, you are going to be limited going to a very wide tire on a 6" wide rim,
regardless of any wheel spacers.

Sorry I derailed OPs thread apologies OP. I actually have a 4.0 with ecco,s and 235-75R15s on at the moment can I go wider?

 

[jrmcafee]

I have 35” tires that are 12.5” wide on a 7” total lift and the 2.5L motor and I’ll agree with the rest of the responses. It’s a complete dog. I bought it this way. I’m working on removing the 3” BL and downsizing to a 31” more narrow tire to recover some sense of acceleration.

 

[mxz800]

My 2004 2.4 has a new set of 235/75/15 I also put new fenders flares that are 7 inches wide so I put on spacers for a wider stance.

Since I'm follically challenged I'll take the wig, I'm to cheap to pay for a hair transplant.

 

[MarvinChumbley]

I bought a TJ with 33’s on it. Can I go to 31’s without having to change anything?

 

[Jerry Bransford]

I bought a TJ with 33’s on it. Can I go to 31’s without having to change anything?

Yes, your engine rpms will just be a little higher than they were with the 33's. You'll likely need to recalibrate your speedometer too which is an easy job. Here's how... http://www.4x4xplor.com/speedo.html

 

[Plumber1]

I bought a TJ with 33’s on it. Can I go to 31’s without having to change anything?

Do you know if the PO had changed the bearing ? if they have not been changed you will be happier with 31's as far as performance goes. Now looks that's up to you

 

[MarvinChumbley]

Yes, your engine rpms will just be a little higher than they were with the 33's. You'll likely need to recalibrate your speedometer too which is an easy job. Here's how... http://www.4x4xplor.com/speedo.html

So I don’t need new wheels or to remove/change the lift?

 

[MarvinChumbley]

Do you know if the PO had changed the bearing ? if they have not been changed you will be happier with 31's as far as performance goes. Now looks that's up to you

I’m not sure. It’s in shop getting new clutch. I don’t care about the looks. My kids talked me into this particular Jeep because of the tires, I suspect. I definitely don’t need them.
Thank you!

 

[Plumber1]

So I don’t need new wheels or to remove/change the lift?

Post some pictures and tire size

 

[Jerry Bransford]

So I don’t need new wheels or to remove/change the lift?

What wheel size do you have now? The last two digits of your tire size will indicate it. You can leave the lift installed if you want or don't mind the look with the smaller tire size.