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4" lift and tire fitment ???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88K5Jimmy, Oct 23, 2001.

  1. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    4\" lift and tire fitment ???

    I was wondering if a 4" lift and 35x12.5x15 on 8" rallys would be enough lift with no rubbing. Or amybe the zero rate add-a-leaves and the same lift and tire combo. Anybody done this? Also, besides steering correction, longer brake lines, gears and correct drive-line angles, will I have to get new/longer driveshafts? Also, how will my stock 10-bolts hold up to street an mild-moderate offroading?
    Thanks
     
  2. SlyDog

    SlyDog 1/2 ton status

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    Re: 4\" lift and tire fitment ???

    The famous question .... Do you want to trim the fenders ? Cause if you flex you will with 35" tires .

    <font color=green>[​IMG]1977 K5 GETTIN IT AWN[​IMG]</font color=green>
    GO BUSH
     
  3. bee32

    bee32 1/2 ton status

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    Re: 4\" lift and tire fitment ???

    I have the same set up and have yet to rub with my new tires. I don't do any rock crawling(due to lack of rocks) but i do ALOT of mud. There hasn't been a time when I rubbed and I have been through some deep gullys and pretty steap hills. I am considering cutting out the fenders due to rust and just to be on the safe side of rubbing. I am triing to build an all around off road/daily driver. You will feel alittle loss of power with the ten bolt if it is stock I suggest either bigger gears or even better get a 12 bolt. I am soon.

    Brian
    83 K-5 4" on 35's
     
  4. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Re: 4

    Bee, others used to say that too. Look closely if you are moving the axle much they will rub. I think we came to an agreement that the 81 &amp; up wheel wells are a little bigger, but not by much.
    '88, I wouldn't sink money into a rear 10B, but that is just my opinion. I have 35x12.50s on my 15x8 Ralleys and it works fine. It keeps the tires under the fenders and that has good &amp; bad points, as well. You could also go with an off brand tire as they are smaller than stated. Then they might fit. A 10" rim would also shorten the tire. The first thing you need to do is decide what is your #1 requirment (tire size, lift hight, body mods, etc.) and work from there. Driveshaft legenth is usually good, but there are no guarantees. I needed new shafts and had to shim my X-fer case for my 4" lift on the '80, the '73 did not need this. The slip yoke cases have more problems with this than the fixed yoke. I strongly suggest ORD's steering box brace. When you do the lift make sure you carefully inspect/replace your wheel bearings and steering parts.

    Jim '80 GMC & '73 Blazer
    Body by Tellico
    <a target="_blank" href=http://www.tellicok5.rockcrawler.com>www.tellicok5.rockcrawler.com</a>
     
  5. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: 4\" lift and tire fitment ???

    Now this is an old question.

    My opinion is that there is no set in stone answer. There are alot of factors involved, such as:

    - brand of tire and it's actual size - there can be some very noticable size differences between two different makes of tires listed as 35x12.50

    - size and offset of rim - from my experience on K5's, the wider rims can actually cause more intereference between the tire and the rear of the fender during turning. I saw this when switching from the stock alloy 7" rims to 10" rims, both with the same offset

    - type of lift use (spring rate or actual lift height) - just like tires, all 4" lifts are not created equally and not all trucks weight the same (which will affect lift height). Also, the more flexible the springs are the more of a chance of the tires hitting the fenders

    - how the vehicle is used - normal street driving should never make the suspension flex as much as hard trail use. My truck has flexible front springs and the swaybar disconnected, I had to do some minor "adjusting" to the rear of the front fenders to keep my old 33's on 10" rims from rubbing.....obviously the current 35's required more trimming.

    Overall, in your case with the 8" rims and under most circumstances you should be okay. If you plan on doing serious flexxed out wheeling, then plan on doing at least a little trimming of the fenders. Don't forget to also check out the front part of the rear fenders.
     
  6. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Re: 4\" lift and tire fitment ???

    My springs are reasonably soft, but even with the sway bar on and the same rims he wants to use I was making slight contact at the back of the front wheel well on the street. That is with BFG MTs (35x12.50). He said he wanted to take it off road, I think the 81 &amp; up fender openings are a little wider, but not that much. You can fit an off brand 35 or a 33" BFG/Swamper with some Rancho (dump truck) springs and it might not rub. Like I said before you need to decide what is important and how it will be used and go from there. Like 6.2 said there is no exact answer to this question.

    Jim '80 GMC & '73 Blazer
    Body by Tellico
    <a target="_blank" href=http://www.tellicok5.rockcrawler.com>www.tellicok5.rockcrawler.com</a>
     
  7. bee32

    bee32 1/2 ton status

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    Re: 4\" lift and tire fitment ???

    Yeah okay, I was wrong. I went out last night to the deepest and steepest gully I could find and had my spotter check it for me as I came down through the turn up and sure enough they rubbed. I have to trim about a 1/2 inch to be on the safe side. I never even felt it but when I got out I could see where it had caught so be ready to do alittle trimming. I now know what to do this weekend before I go tagging saturday night. Thanks for setting me straight I sure would hate to have to buy two sets of tires due to trusting feel instead of a second pair of eyes.

    Brian
    83 K-5 4" on 35's
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: 4\" lift and tire fitment ???

    I have never noticed mine rubbing but a good look at the tires says that they did once. If you rock crawl, you'll most likely have to do some serious cutting. In the mud, they won't rub 'til you bounce hard or land from a wheelie.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  9. wayne

    wayne 3/4 ton status

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    Re: 4\" lift and tire fitment ???

    I guess I will through my $.02 in here. I have a 4" Superlift with ORD shackels and a Dana 60. So I should be clost to 5" lift. I have 15x10" with 4 1/8" backspacing and 35x14.50 SSR's and they rub both front and back without flexing. I have no choise but to trim because I don't even want to think of what will happen when I flex it.[​IMG]

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  10. txbartman

    txbartman 1/2 ton status

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    Re: 4\" lift and tire fitment ???

    I have 4" lift with 10" rims and BFG 35x12.50 MTs. With mild (very mild) off-roading and street driving I had no problems and the tires filled the wells nicely. Once I did some more serious off-roading, they rubbed like heck! I didn't damage my tires, but I bent up the insides of the fenders pretty good. I didn't need a spotter to tell me they were rubbing. You could HEAR them popping against the fenders up and down the trail! Ask sluggo45acp! It also made it dangerous as I would cross ravines or gulleys where I got some good flex as the tire would get jammed into the wheel well preventing me from being able to turn. That made me go directions and attack at angles I did not intend to persue!

    I trimmed my front fenders back to the inner wheel well. I also installated a set of Bushwacker cut-out flares to make the cuts look nice. I also installed a set of ORD 4 1/2" competition bump stops to reduce how high the axle could travel towards the frame. I am about to install (sitting in a box in the garage) ORD HD front shackles (which are a little longer) and an ORD 1" body lift. With all of those mods, I hope to have eliminated my rubbing problem.

    And, BTW, I run a Rough Country lift. And from what others have said, it is one of the stiffer sets of springs. As far as the rest of your question, you pretty well covered everything you will need. I did not need a longer front driveshaft, but some have. It really seems to vary from lift to lift, truck to truck. I would also consider a the swaybar correction/disconnect kit from ORD. It improves the ride on the street by correcting for the 4" lift while providing great handling off-road with the quick disconnect. I have been very pleased with mine. If you do this, might as well replace your bushings while you're at it.

    Best of luck!

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     

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