Tire size fitment question

Discussion in 'Lifted & Offroad Suspension' started by lifted03z71, Dec 20, 2012.

  1. lifted03z71

    lifted03z71 New Member

    hi i have a 2003 lifted chevy truck with a 6 in superlift and 3 in body lift, i need new tires and was wondering if a 37 14.50 would fit under it without rubbing. i have 35 12.50's on it now my wheels are 10 in wide. need some advice.
  2. SurrealOne

    SurrealOne Former Member

    Welcome! :great:

    I'd expect you'd have to trim. However, that's just a suspicion, as I've not dealt with tires that large, before. By the way, I seriously hope you're changing your gear ratios as you're moving up (so that your truck maintains some low-end grunt instead of becoming a dog) and that this is on a 2500 HD or better and not a 10-bolt 1500! (I'd be worried about the rear diff on a 1500 and also concerned about snapped axles on a 1500...)
  3. retired2001

    retired2001 New Member

    Welcome to the G M T C !
  4. donyms

    donyms New Member

    Welcome to the club, it's good to have you aboard............. :glasses:
  5. Conlan Rose

    Conlan Rose Super Moderator

    :sign0016:to the GMTC
  6. BillM

    BillM New Member

    I can't answer that, but welcome to the club.
  7. mfleetwood

    mfleetwood Moderator

    Thread title changed to relate to topic and moved to this section.
  8. lifted03z71

    lifted03z71 New Member

    The truck is a 1500 with stock gears and axles, there's 186k on the truck now and hasn't had any problems as far as axles go, thanks for the help
  9. weswins

    weswins New Member

    Hey, I work at a truck accessory shop and can tell you without a shadow of a doubt that those tires WILL RUB.
    This being said, they will rub on the rear of the splash guards on the front wheel wells and a small amount on the front bumper. If you do not trim these parts, your tires will quickly take care of that for you the first time you head offroad.
    As far as axles, drive it nicely, dont try burnouts on dry pavement and dont expect much longevity on hardware if you wheel it offroad.

    After all that, do it and enjoy it, there isnt much harm you can do in upsizing tires after 35's, the stress is already there.
  10. mfleetwood

    mfleetwood Moderator

    With stock gears (I'm assuming 3:73s?), your truck is pretty sluggish with those 35s already. As @SurrealOne mentions, a changing of the gears should be something you are considering as well if you are moving up another 2" or so in diameter.

    There is also a rule of thumb regarding tire width as it relates to rim width. I can't remember exactly what it is (someone will probably respond with the info if you need it) but I think if the tire is 4 1/2" wider than the rim, that may be too much and you'll have to change rims as well.
  11. SurrealOne

    SurrealOne Former Member

    The best rule of thumb is to check with the manufacturer as to the maximum size tire for which a wheel is designed ... and stay within that spec. :)

    You haven't stressed it, yet. If you move to shorter gears to restore lost torque and add even more stress with 37's (heavier than your 35's) and then go wheel it in mud pits or the like because you have the 37's to do it ... the axle and diff will be at risk, as what's in a 1500 is lighter duty than what's in 2500's. That's all I was trying to warn you about. If you just want a pavement monster you should have no problems...
  12. lifted03z71

    lifted03z71 New Member

    If I upgraded to a 37 12.50 would the tires still rub? I trimmed the front bumper on the bottom so that it would eliminate any rubbing on the bumpe
  13. SurrealOne

    SurrealOne Former Member

    It's tough to say. Even though your width would remain the same as what you currently have, you'd be increasing the diameter by 2 more inches, which could have interesting effects when you've got the wheel turned all the way in one direction, when your shocks are compressed, and most probably when both occur at the same time.

    You should probably take some measurements with your truck in each of those conditions and see if you have 2 more inches of clearance. It won't be a perfect answer but it'll give you a pretty good idea of whether or not you've got more trimming to do if you upsize by another 2 inches in diameter.
  14. aloxdaddy99

    aloxdaddy99 New Member

    With tires the size you are looking into it isn't the back I would be the most concerned with. It's the front! The front IFS suspension is at the upper range of being capable with 35's. 37's to me is asking for trouble. Why? The added weight of the tire which adds additional stress to what concider a "weak" suspension. If you plan to wheel this at all you will be replacing parts real quick.

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