Topic: Help with tire choice, on 04 2.4L TJ

[streetmaster]

Hey fella's its been awhile ha?

Still truck'in around in my 2004 2.4L Electric Lime Green Pearl bundle of joy (TJ), and im love'in every minute of it. Yet i still have those pesky P225/75/15 Wrangler GSA's, which are down to the indicators, meening there darn nere bald. It had 18,000 on her when i got her in 06, and its got 43,000 so far. Has'nt let me down yet,  But its time to put some new shoes on her (LOL). I have in the gerage 4 brand new P275/60/15's that a lot of guys use on there 1/2 ton chevy pu's, which is what i got them for. But i got rid of the truck i was work'in on but kept the tires. They are 28" tall like the Wranglers on the jeep, just a bit wider. But i'dd have to get rims for them, because there to wide for my 15X7" ECCO's alloys.

They might look a bit stupid to some of you out there, because they'ed probly look to short and stick out to much, which would make me want'a  and hide my head when another jeep passed by, and maybee wave or even laugh 

Or i can, for the same cost of the rims, get some recapped 31's to put on the ECCO alloys, for $60 a pop. But im affraid that i'll drop 5 mpg, with the 4.11's. And at $30 buck for 15 gallons of gas, and 60 mile round trips to work and back every day, it could be a pretty big hit.

Im not gonna slap gears in it untill she's paid for, which wont be for another 2 yrs.    I dont ever have time to wheel my jeep, and there is'nt any place thats close enough to home, so i figured that recaps would be ok for a DD.

So if anyone has any wopping oppinions about how my fuel milage will SUCK with 31's (Please Advise)

[JeepGeek666]

I dont think the 31's are going to hit you that hard in the MPG.   I have the same problem and same jeep.   I drive mine 75-120 miles a day but I am thinking of getting 31's.   With the 4:10s in the rear they should turn OK.   THe 2.4L doesnt have as much low end as the 2.5 as far as I know but in the upper band there is more so at speed you may do OK.   I dont think the 31's will fit on your stock rims, you may need 8" and possibly spacers.   TJ's clear 31's stock better than the YJ's do but they may still rub the wells during hard turns.   

The 31's on my old YJ would rub the leaf springs when I cranked it and I had to shave the feneder flares a bit to reduce rubbing.     5th gear on certain parts of the highway may be a problem tho.....but even with stock tires hills make me drop it to 4th.       My YJ had a 6 cyl. and I had to drop gear going over the berkshires in Mass. with the 31's on as well.    Give it a try, you can always go back to 225's if its not working...or 235's.

[streetmaster]

ThanX for your responce, start'in to feel kicked towards the curb LOL    Yeah the 2.4 is supposed to have about 25 hp more than the 2.5 does which is no big deal i suppose. Im just more or less concurned about the mpg thing than anything, because if by switching to a tire that 2.5 to 3" taller than the one's that i have on, might cost me an extra 20 buck a week in gas, i might wait untill i can gear for a set of 32's.

[TahoeYJ]

I have no idea how the newer 2.4's do on gas with larger tires, but when I was running stock gears 33's on my YJ I lost 5th gear for the most part, but could still get 14-16 MPG on the highway, and about 14 around town. With 4:88's it went up some but not a whole lot. With 31's you should still be able to use 5th gear and retain the same or close mileage. Also 25 extra HP is a decent amount, esepcially in a little 4 cylinder. That extra 25 HP will really help keep larger tires rolling at highway speeds

Keep in mind that All Terrain tires generally get better mileage than mudders, although I can get in excess of 18-20 MPG if I baby my rig and that's with 35's. I dropped in a rebuilt 2.5 with about 40K on it and added a 4.0 TB (Don't think that'd work on the 2.4...), and that's when my mileage really went up.

[aw12345]

31's run ok on a 2.4, I ran those for close to a year with 3.73 gears should work pretty well with 4.10's
you might drop 1 mile to the gallon or so over stock

[streetmaster]

Yeah, im just try'in to get some perspective on it, because i've had my jeep since 06, i figured some one's had to have ran larger tires on a 2.4 TJ by now. Besides, if i keep it right at 2500 rpms do'in 65 in 5th gear on the 225's, I stay in the 20+ mpg range.

4.88's with 32's should run just like stock from what i understand, meaning that my 2.4 TJ came stock with 215/75/15's (27") and 4.11's, and 4.88's with the 32's would run better that my 225's and 4.11's in there now.

If i warrent so chicken sh#t about it, i would just say the hey with the warrenty and go for the 4.88's and 32's, and be done with it.  

[aw12345]

I tun 32's and 4.56 gears and am happy, however regearing, tires and lift does hurt milage.
For a bit of wheeling and street driving 31's and stock gearing works pretty well

[streetmaster]

Yeah now that gas prices are going down some, i think im gonna shoot for the 31's on my stock 15X7" ECCO alloys for now. I mean (MAN) a few months ago $20 bucks would only give me 1/4 tank. I just stuck $20 bucks in, with the needle between empty and 1/4 tank, it got me up to just below the full mark at a $1.78 a gallon. 

[JeepGeek666]

I dont think 31's will fit 7".   You will probably have to get 8" ...so 15x8" wheels.  You can find some nice wheels for a decent price at summit racing.  They even sell them with the back spacing already done.   

I'm running 225's on my 2.4 for now because like you I was concerned with the MPG with my delivery job.... however, if the xmas funds are decnt this year, I might get a set of 30" or 31" BFG A/T or M/T.   I'd prefer the MT as I like to do some wheeling on the old logging trails near my house but the A/T's should be able to handle it.   

I'm thinking a 1.5-2 inch lift come tax return time as well for a little more clearance.   For now, I dont want to go too high....have a 2 year old and my jeep is my daily driver.  He weighs a ton because he is the size of a 5 year old ( over 3' tall and 50lbs) and I usualy gotta load him in through the back or else he will make a mad dash for the drivers seat to play with daddy's jeep ha ha.   Gotta love it! 

Whats the avg cost and what am I lookin at difficulty wise in putting in an SYE and or dropping the T-case?   Anyone?

[Jeffy]

3.5" difference between wheel width and tire width is acceptable for most tires.  A 31x10.5R15 will fit on a 15x6" with some bulging.  15x7" would be better.    A lot of people run 31x10.5R15's on 15x6's around the world though.

Really study up on backspacing if you don't know what it is.  It is important to get it right.  Running too wise or too narrow isn't good.

[JeepGeek666]

back spacing explained      http://www.customtacos.com/tech/index.php?article=40

Ive heard 4.5 to 3.75 is common spacing for a set of 31's.   

I didnt know about spacing when I had my YJ and my tires always rubbed my leafs when I would make a tight turn.   

[JeepGeek666]

here's how to measure  http://www.ehow.com/how_2113075_measure-back-spacing-car-wheel.html

[Jeffy]

back spacing explained      http://www.customtacos.com/tech/index.php?article=40

Ive heard 4.5 to 3.75 is common spacing for a set of 31's.   

I didnt know about spacing when I had my YJ and my tires always rubbed my leafs when I would make a tight turn.   

3.75" would be a bad choice.  That will out the tire a few inches outside of the stock flare when there is no need to do so.  For most Wranglers, you want something around 4.75" and 4.5" for most tires.  When you start getting to 33's, you'll need to turn out your steering stops a bit.