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Bigger tires on stock suspension

Discussion in 'Wheels and Tires' started by Howard Rogers, Feb 16, 2020.

  1. Howard Rogers

    Howard Rogers Junior Member

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    First Name:
    Howard
    Truck Year:
    1986
    Truck Model:
    GMC 2500
    Engine Size:
    350
    what is the biggest tire i can run on stock suspension.. 1986 gmc 2500 4x4... thanks
     
  2. RecklessWOT

    RecklessWOT Full Access Member

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    Truck Model:
    V10 Suburban Silverado
    Engine Size:
    350 TBI
    I ran 31x10.5x15s on my 87 Suburban 4x4 (1/2 ton) when it had stock suspension, no clearance issues whatsoever.
     
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  3. 78C10BigTen

    78C10BigTen Full Access Member

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    350
    Ive got the same size on my 2wd 78 with saggy front coils and no issues.
     
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  4. 80BrownK10

    80BrownK10 Full Access Member

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    I am pretty sure you can fit 32's
     
  5. RoryH19

    RoryH19 Full Access Member

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    I'd say 31's. I had 33x12.5 on my k20 but needed a 2" lift.
    The tires would hit the back fender opening unless you want to clearance.

    My k5 came with 31x10.5 from the factory.
     
  6. TubeTruck

    TubeTruck I like anything fast enough to do something stupid

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    400ci, 350ci
    If you're using the factory rims then 33x10.5x15. That's what I run. 12" wide you'll need a lift.
     
  7. bucket

    bucket Super Moderator Staff Member

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    I had a 4x4 3/4 ton Suburban that ran 33"x12.5's and factory wide steelies on bone stock suspension. No rubbing even offroad.

    8625464145_baf5e7d167_b.jpg

    But there's a definite gray area with 33's. A 1/2 ton will almost certainly need trimmed. The exact same wheel and tire combo can actually rub on the same truck with lift springs. Soft lift springs can provide much more axle droop, so if one side is dropped and the other side is stuffed, it can put the stuffed tire closer to the fender than with stock springs.
     
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  8. waterpirate

    waterpirate Full Access Member

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    I have run 31x10.50x 15 on my 87 stock short box 4x4 for decades. Even when airing it out they do not rub.
    Eric
     
  9. Craig 85

    Craig 85 Full Access Member

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    First picture is Frankenchevy's truck. He is running 285/75R16's (32"x11") with 16x8's with 4"BS on his K30 w/o rubbing. They would probably fit a K20 without issues. Second picture is my truck (also K30) before I bought it with old school 33x12.50x16.5's on a 9.75" wheel. It has minor trimming on the front fenders.

    [​IMG]
    Original K30.jpg
     
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  10. Shorty81

    Shorty81 Baby Boomer

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    31x10.50x16 no rub.

    IMG_20171124_151430_hdr.jpg
     
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