Advice on tire size increase please

twobit · 11-12-2009, 11:02 AM

OK, I used the search function for an hour+ or so and it did not completely answer the question I have...

Got the Wrangler last month. Love it, but it needs bigger tires.
It now has 215-75-15 on 15 x 8 wheels (yes a very goofy looking combination). I believe the 1st owner got bigger wheels first and before getting bigger tires for those, he sold it, so the tire / wheel upgrade was only half done.

Jeep is a 2006 Wrangler X, 4.0 liter 6 speed manual with 3.07 gearing.

I will use it 85% on 2 lane country roads at 60 to 65 MPH with some hills. Off-roading will be mostly dirt ranch roads, pastures, gravel / dirt trails. No extreme trails.

I want to go to 30" or 31" AT tires like a General Grabber AT2. The current 215's are 27.5" in diameter. So I would be going up to 29.5" or 30.5".

I dont want to it to become a dog because of the 3.07 gears with too big of a tire diameter. I probably will never regear it. If I lift it, it would only be a 2" BB.

I'm guessing I will be happier with the performance/ power the 30" tires will offer vs. 31".

Would really like comments from those of you with the 4.0, 3.07, six speed setup as to what tire size works well.

Also to re-gear the speedometer on an 06, is it electronic or a speedo gear change?

Thanks.

**Imped** · 11-12-2009, 11:05 AM

Go 31's. Your 6 speed will help take up some of the suckiness of 3.07s due to it's lower gearing. And I thought I would never regear or go any larger than 31's either.....

Specbill · 11-12-2009, 11:34 AM

The 3.07's are going to cause you to use the gearbox more regardless so I say 31's over the 30's, Both you will have the same performance challenges but the 31's will look better. Have fun.

Bill J.

Wif · 11-12-2009, 11:56 AM

I ran 31's with 3.07's and it was OK .. you'll use 4th a bit more on hills.
I found with 31's my speedo was spot on as well (GPS verified) .. it was off before.

**Imped** · 11-12-2009, 12:06 PM

The OP has the NSG370 6 speed, not the NV3550. Due to the low first gear and low OD (6th), the 3.07's will be more livable than with any other transmission Jeep used.

**TheBoogieman** · 11-12-2009, 12:14 PM

Go with 31's or you'll regret it.

**TheBoogieman** · 11-12-2009, 12:15 PM

Quote:

Originally Posted by imped4now

And I thought I would never regear or go any larger than 31's either.....

Very common mistake to new Jeep owners.

Bishop Creek · 11-12-2009, 12:33 PM

Quote:

Originally Posted by TheBoogieman

Go with 31's or you'll regret it.

Never thought I'd see you say that!

**TheBoogieman** · 11-12-2009, 12:48 PM

Quote:

Originally Posted by Bishop Creek

Never thought I'd see you say that!

That's for him only.I'm starting to think my 35's are shrinking.

**kellerumps** · 11-12-2009, 12:50 PM

Quote:

Originally Posted by imped4now

And I thought I would never regear or go any larger than 31's either.....

I thought that as well......then I went wheeling once and acquired the JEEP Wallet syndrome. Now I'm obsessed.

twobit · 11-12-2009, 12:59 PM

had question about post 5, but then realized #2 was same author and that answered it.

As it is now, I often shift 1 to 3, skipping second because 1 & 2 are so low, you dont build up much speed in second. Maybe 31's will make 1 & 2 taller and not make first such a granny gear.

**TheBoogieman** · 11-12-2009, 01:07 PM

Quote:

Originally Posted by twobit

If I am understanding post #5 correctly, my 6 speed ratios help offset the power loss of 31's ? And post #5 vote is for 31's ?

Yes and yes.

**TheBoogieman** · 11-12-2009, 01:52 PM

Quote:

Originally Posted by twobit

had question about post 5, but then realized #2 was same author and that answered it.

As it is now, I often shift 1 to 3, skipping second because 1 & 2 are so low, you dont build up much speed in second. Maybe 31's will make 1 & 2 taller and not make first such a granny gear.

It will.When I had a 6 speed with 3.73's and 31's,I always took off in 2nd gear to avoid shifting in 15 feet.

BoneyMan · 11-12-2009, 01:56 PM

Yeah, I put 31x10.5's on my stock '05 TJ and it looks superb. I'm rolling on 15x7's but I don't imagine that will make too big of a difference. The 31's just make the Jeep look like it's supposed to stock. Anything less will be disappointing. Also, I second the starting off in 2nd gear from the above poster.

**kellerumps** · 11-12-2009, 02:12 PM

Quote:

Originally Posted by TheBoogieman

It will.When I had a 6 speed with 3.73's and 31's,I always took off in 2nd gear to avoid shifting in 15 feet.

I take off in 2nd gear with 3.73's and a 5 speed and 31's.

To the OP....go with 31's. You will be alot happier in the long run.