Tires:how much taller?

H

hammerhead

NAXJA Forum User

Location

Nebraska

• Aug 5, 2005

• #1

I've got a 92 with 215/75/15's ,and a 4.0 and 5 speed , and 307's. It's time for new tires and was wondering how much larger I can go in tire size before the jeep's performance and fuel economy becomes adversly affected?

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #2

Do you have any lift? If not, you can run 30.9.5 max

 

H

hammerhead

NAXJA Forum User

Location

Nebraska

• Aug 5, 2005

• #3

2 inch lift

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #4

If your worried about power and gas mileage, I run 265/75/15. I can still burn rubber on the street, and I stil get 230 miles out of a take of gas. I rub on full turns.

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #5

sorry i got a 3inch lift rustys Yall know Rustys is in Alabama so I drive there for parts, cheaper than anywhere!

 

H

hammerhead

NAXJA Forum User

Location

Nebraska

• Aug 5, 2005

• #6

265's are about 30 inches ?

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #7

There alil bigger

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #8

http://www.wscope.com/tire_conversion_chart.htm

 

H

hammerhead

NAXJA Forum User

Location

Nebraska

• Aug 5, 2005

• #9

I was wonderin cause the my 307's are pretty tall, probly have to stay in 4th allot more on the highway,?

 

B

BoC

NAXJA Member #1266

Location

Alabama

• Aug 5, 2005

• #10

No youll be fine. I just put new axles under my buddies XJ from an auto, which had 3.55 gears. He loves the new found torque, you'll be fine man, his truck still had good power on the highway.

 

RichP

NAXJA Forum User

Location

Effort, Pa

• Aug 5, 2005

• #11

I run LT235/75R15 BFG AT/KO's on my 98 5speed with 3:07's. I don't use 5th much till I get above 65mph and spend most of my time in 3rd around town.

 

H

hicksrcool426

NAXJA Forum User

Location

connecticut

• Aug 5, 2005

• #12

yeah, i dont use 5th much either, unless im on a long trip. i get on the highway in 3rd, and i can keep it there till around 75 if i have to. its actually kinda hard to keep it in 4th on the streets and still do the speed limit, if theres a speed trap, a slow car ahead of me, or anything happens that i have to slow down for, i almost always have to down shift, a lotta turns around where i live i even have to go down to second. im hoping to put axles from an auto(3.55) in too. 3.07's arnt too hot off road either, especialy when ur following someone in mud, and ur trying to keep ur speed/rpm's up, and u have to be carfull to keep your distance. i end up using low range more than my old truck

 

H

hicksrcool426

NAXJA Forum User

Location

connecticut

• Aug 5, 2005

• #13

anyways though, i'd only run 235/75/15 stock. my buddys got 30x9.50's on his 89. i think there somewhere around the same, 235's might be a little smaller. 30x9.50 sounds cooler though, lol

 

H

hammerhead

NAXJA Forum User

Location

Nebraska

• Aug 6, 2005

• #14

hicksrcool426 said:

anyways though, i'd only run 235/75/15 stock. my buddys got 30x9.50's on his 89. i think there somewhere around the same, 235's might be a little smaller. 30x9.50 sounds cooler though, lol

Click to expand...

What size do you run?

 

H

hicksrcool426

NAXJA Forum User

Location

connecticut

• Aug 6, 2005

• #15

im running both 225's, and 235's, i have 3 sets of tires. i can get the 235's to rub if i try, and i can get the 225's to come close, but that was with my left rear about 6 inches off the ground. its stock hight, for now...

 

C

csr_011

NAXJA Forum User

Location

Lincoln, NE

• Aug 6, 2005

• #16

I was going to with 30 X 9.50's last time, but the tire guy had a good point. Good luck finding a good spare in that size should something go wrong. I went with the 235/75/15's. My rims are a little offset so they dont rub at all anymore, otherwise the 87 XJ is stock...

Cory

 

Eagle

Lifetime NAXJA Member

NAXJA Member

Location

Terra Firma

• Aug 6, 2005

• #17

hammerhead said:

I was wonderin cause the my 307's are pretty tall, probly have to stay in 4th allot more on the highway,?

Click to expand...

Nebraska is pretty flat. You'll be able to use 5th gear on the highway, but you WILL lose performance, and you WILL lose gas mileage. My XJ is a 5-speed with stock gears, I've been there and done that. I use the 30s only for going off-road, but the 4 hour drive from home to Paragon with the bigger tires on makes me very aware of the difference.

I am currently running a set of half-used up 235/75R15 BFGs, but when they are finished off I'll go back to 225s for the economy. My XJ actually got the best gas mileage when I was on the original 205/75 tires that came on it. Every increase in tire size has hurt the mileage, which just confirms what I have always thought -- 3.07 is too tall for axle gearing in the XJ.

 

H

hicksrcool426

NAXJA Forum User

Location

connecticut

• Aug 6, 2005

• #18

Eagle said:

3.07 is too tall for axle gearing in the XJ.

Click to expand...

i agree. do u think that switching to 3.55's would make a big differance in gas millage with 235's?

 

F

Foto4x4

NAXJA Forum User

Location

East Bay, CA

• Aug 6, 2005

• #19

I'm running 30x9.5 with a 5 spd and 3.07 gearing (2.92 effective). I don't have any problems with power, I only have to go down a gear on 5%+ grades. I average 22mpg so I don't see a terrible change in gas mileage. I can even crawl in 4LO at idle, on an incline. Granted, if I went to 31 or 32 inch tires I would regear to 3.55, which would give an effective of 3.27 or 3.17 respectively.

Is my Jeep just special or why is it that you all complain about the 3.07 gearing and a 5spd?

 

B

black93xj

NAXJA Forum User

Location

Ohio

• Aug 6, 2005

• #20

My 93 sport 4.0 auto had 225/75/15s and i put on 235/75/15s and mileage is still good and it will lay rubber. I know mines a auto but still... Oh and mine never scrubs i don't care how much you flex, it has plenty of room. And my girlfriends 94 xj has 31s and she gets better mileage than i do!