What size?

Discussion in 'Tires / Wheels' started by greene, Mar 14, 2013.

  1. greene

    greene Full Access Member

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    I have a 2003 Libberty that I am going to put a Tommudd's Econo 3.5" Lift Kit KJ (Tommudd's Econo 3.5" Lift Kit) on it in about 2 weeks. I do not know what tires I am going to run on it until I get it lifted and take some measurements. I would like to go with 265/75R16.

    Gears:
    I will be changing my ring and pinion set to 4:10 or 4.56. But it is not going to happen for a few months.

    Now the question: the Liberty 3.7 has plenty of power to push 265/75R16 or 275/70R16 even though re-gearing it is preferred and I know I will lose some power.
    Is it the transmission cannot handle it? Or the shifting points get thrown off?

    I would like to know what to expect.
    Should I just go with the 265/70R16 until I get the gears and then put them on my wife’s liberty after we put the OME and new shocks and go to the 265/75R16 then?

    265/70R16
    Overall Diameter = 30.7
    Width= 10.9

    275/70R16
    Overall Diameter = 31.0"
    Width= 10.9"

    265/75R16
    Overall Diameter = 31.9
    Width= 10.7
     
  2. LetFreedomRing

    LetFreedomRing Full Access Member

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    As far as gears go, you are limited to 4.10 in the front. Unless you go with the JBA steel front differential.

    As long as you plan on regearing, driving around with 265/75/16 tires shouldn't be too terrible. Many people have driven around longer than that before they regeared. Just expect not to use overdrive much until you do.
     
  3. tommudd

    tommudd Moderator Staff Member Moderator

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    If its going to be a few months before you re-gear, I wouldn't go to 265-75s yet. From experience even on flat straight roads it was a dog, once you got over 75-77 you could run with overdrive, anything under that all it would do is keep shifting back and forth. Gas mileage went into the hole and it ran hotter as well. Even with 245-75/265-70s you'll notice a difference but at least you can still use OD most of the time .
    So I'd strongly advise against running 265-75s and stock gearing
     
  4. greene

    greene Full Access Member

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    So Tommudd would the 275/70R16 be ok? Or do I need to go with the 265/70R16?
    265/70R16
    Overall Diameter = 30.7
    Width= 10.9

    275/70R16
    Overall Diameter = 31.0"
    Width= 10.9"
     
  5. tommudd

    tommudd Moderator Staff Member Moderator

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    I wouldn't go anymore than the 265-70/245-75 ( both basically the same height pretty much
     
  6. osufans

    osufans Full Access Member

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    I'll be honest...all this talk about can't run on 265's until you regear is bull.

    I'm running 265/75R16's. Have been since last year. I have no problems taking off, Jeep still have plenty of power. Does it get a little doggy between 45-55?? Sure. Until you press down the accelerator and it downshifts, then takes right off. Unless you are the random few who seem to only go 45 MPH around here, and complain about the transmission hunting between 3rd and 4th because the overall gearing is now too tall, you'll be fine.

    I haul a lawn trailer with about 1000# on it and still have no problems. Like I said, it's mostly just a bunch of bull.

    *** I'll add the disclaimer that if you're doing some serious trail riding, and need the lower gear ratio for crawling, then yes, maybe you'll want to re-gear. For everyday driving, you'll be fine. *****
     
  7. osufans

    osufans Full Access Member

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    I'll also add, I leave my OD on all the time. But yes, my MPG went to the crapper. I now only get about 14MPG, from the 17-18 I got before when I was stock. :rolleyes:
     
  8. tommudd

    tommudd Moderator Staff Member Moderator

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    SOOOOOOO
    it's not BULL
    You said it yourself right there , mileage went down etc
    Just swap to 4.10s if you want to run 265-75s !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:shrug:

    We need to take a ride from Columbus to Cambridge and back, count how many times your's switches back and forth from OD to drive and then do the same with mine or another one that is set up right
     
    Last edited: Mar 18, 2013
  9. 4x4kayak2112

    4x4kayak2112 Full Access Member

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    What about running a light weight 265/75 tire like a p street tread style. I know that 245 duratracs weigh more than a p265/75 street tire.

    I run street tires daily and when I go offroad just change out the set.

    Just a thought

    Sent from my SPH-L710 using Tapatalk 2
     
  10. tommudd

    tommudd Moderator Staff Member Moderator

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    Height is what affects the overall gearing
    Weight affects the power it takes to turn them over no matter the height
    add both and you're seriously down on power
     
  11. tjkj2002

    tjkj2002 Full Access Member

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    Can you run them with stock gears? Yes but like you stated your mpg's will go way down,your getting worse then you think since your speedo/odo is way off now.It also makes your engine and trans work harder which produces more heat,more so in the trans which will reduce it's life alot.Yes it is true your damaging your trans,it's most likely running at least 15-20 degrees hotter then it should be and 15-20 degrees can kill a auto trans pretty fast.

    Also where you live it's not as bad as say someone who live where I do at over double the elavation and alot of mountains to go over.


    I run 5.13 gears with 35" tires and truthfully it's not low enough for the 3.7 and the area I live in, I also have the better trans(45RFE),5.38's would have been better.
     
  12. osufans

    osufans Full Access Member

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    I am running p rated tires, so that may also be the difference where some have complained about not being able to run 265's.

    As far as the issue about tranny running hot or gas mileage...whatevs. I see folks running 33's on 4cyl Yotas. Heck, I ran 33's on my Ford Ranger with no problems, and it only got 14-15 mpgs. I realize that things can be done to improve performance after going to 265's, but that doesn't mean they have to be done if you don't mind the difference. This isn't a discussion about who's rig is the most perfect. It's about what works and what doesn't work. I'm pointing out that just because you don't like it, doesn't mean it doesn't work.
     
  13. greene

    greene Full Access Member

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    What about running 4.56 with 265/75R16? I do plan on pulling a little 18’ Travel trailer from time to time.
    I also have a little Ford ranger 4x4 that I have 35s on with 4.88
    [​IMG]
     
  14. tjkj2002

    tjkj2002 Full Access Member

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    I've seen 54" bogger on a Sami(had rockwells) and running a 1.6 four banger,it's all about gear ratio.


    Run what ever you like but when it fails don't come on here and cry about it,which many do even when told how to prevent it but are super cheap.
     
  15. osufans

    osufans Full Access Member

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    Gear ratio only goes so far though. Even with the right gearing, you can put too much stress on axle shafts.

    And it's not just about gear ratio. It's also about HP/Torque. My '05 Hemi Ram had 3.55 gears and was running 33" tires. You're gonna tell me that that gear/tire combo was too tall? That thing smoked pulling from the line. It made punk kids driving sporty compacts go home crying to momma.

    So my point here is, while yes, I do agree there are optimal tire/gear ratio combos for specific applications, not all of us drive our vehicle under the same application. What works for one of us, may not work for all of us. That being said, I'm also saying that just because something works perfect for you, doesn't mean that's the only solution out there.

    Sorry to beat a dead horse, but as long as the dead horse keeps getting drug out here, I'll keep beating it. :beatdeadhorse5: :D
     
  16. greene

    greene Full Access Member

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    What about running 4.56 with 265/75R16?
    I do plan on pulling a little 18’ Travel trailer from time to time.
     
  17. TheBlueKJ

    TheBlueKJ Full Access Member

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    Unless you plan on getting the JBA steel front diff or an SFA swap you can only go 4.11s in the front
     
  18. greene

    greene Full Access Member

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    My Libby is still 2WD. I do plan on Converting it to 4wd with a SFA in about a year.
    It will end up with 33 on it.
     
    Last edited: Mar 20, 2013
  19. tjkj2002

    tjkj2002 Full Access Member

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    In a sense your right but also wrong.You can overcome the lack of gearing with torque but you can overcome the lack of torque with gearing also.

    Take that Ram with the 5.7,it does not need lower gears to turn 33" tires as it has enough torque unlike a KJ with the 3.7 which has about half the torque of the 5.7 will need lower gears with 33" tires(at least 4.56's,4.888's would be better) to get back to near stock performance and mpg's.
     
  20. osufans

    osufans Full Access Member

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    First off, the 3.7 has a reported 235 ft/lb of torque, while the 5.7 (in 2005) had 375 ft/lb. That's not exactly half.

    Secondly....this isn't a discussion about getting back to the original MPG's or stock performance. This is a discussion about what size tires can be run. As I've been pointing out time and again, as long as you are willing to sacrifice the minimal loss of performance, you can run 265's without an issue. I have no issue with the suggestion that "hey, btw...if you do go to 265's you may want to consider regearing, as you'll lose MPG's and some power." But no, it's more like "You can't run 265's without regearing, or you'll break your mother's back, burn down your house, bring on the apocalypse, and then your Jeep will blow up." ;)