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What size lift should I use?

Discussion in '1936-Present Suburban' started by BanksBurban, Apr 11, 2002.

  1. BanksBurban

    BanksBurban Registered Member

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    I have an 87 3/4 ton with stock LT235/85R16 tires, towing pkg (HD rear springs) and running boards. It came with 4.10 gears and a TH400. It also has a GV overdrive unit, but it still screams on the highway. I want to lower the RPM's to get better milage and the easiest way I can think of doing this is to lift it with bigger tires. Are 33's big enough to make a difference? or do I need 35's? I use this truck to tow, so I don't want to go too big. And what size lift would I need for 33's and/or 35's?
     
  2. DesertDueler

    DesertDueler 1/2 ton status

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    Well since you tires are equal to 32s I would say to go to 35s. You can get away with a 4" lift if you dont wheel. If you wheel with it, then you can always trim the fenders. If you dont want to trim the fenders you need to go with at least a 6" lift. Both my vehicles run a 4" lift and 35s. Both rub alittle when I flex it out, but have clearenced themselves out so they hardly will rub unless full stuff and wheels turned.

    Dan
     
  3. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    i run a 4" and 36" TSLs and like it a lot but i'm going to do a 3" body lift soon.
     
  4. chvyhs

    chvyhs 1/2 ton status

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    I have a 6" lift with 36's and I do plenty of towing. I did have to trim the fenders a lot so they wouldn't rub. I don't know what you're towing but I tow anybody that breaks down when we go out. My loads are around 7000lbs. Like DesertDueler said you can get away with a 4" and 35's if your not flexing it too hard. Good Luck.
     
  5. Smurfmobile85

    Smurfmobile85 1/2 ton status

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    Our 85 was exactly what you have (we had 4 hubcaps too) and now we have 4" of lift and 35's on 15" wheels. It doesn't scream anymore! Did a little trimming and self adjusted some parts we forgot to trim, but 4" was enough to start with and we can still tow without too big a drop hitch.

    I have a question for everyone else... when we lifted it we disconnected the lever to the rear diff for brake proportioning.... should we extend it and reconnect it? What have you done?

    Deana
     
  6. chvyhs

    chvyhs 1/2 ton status

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    What lever are you talking about? I didn't see anything like that on my '90 3/4 ton.
     
  7. BanksBurban

    BanksBurban Registered Member

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    I don't wheel the Suburban. It's strictly a tow vehicle. I mentioned that I had running boards cuz they hang low and I didn't want to do any fender trimming. It's in too nice a shape. Would a 4" lift and 35's clear the running boards too? And would I have to lengthen the driveshafts or drop the t-case at 4"?
    Thanks for the help guys!
     
  8. K5DRAGER

    K5DRAGER 1/2 ton status

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    He's talking about the rear brake weight proportioning lever valve. I had a 88 3/4 ton with a 6 inch lift and 33's that I towed my mud drag truck with. I had it disconnected for a long time until I did a brake job on it and found out the rear brakes where not worn. From my understanding the more weight on the rear the more the valve opens to let the rear brakes work more. I decided to just remove it and splice the lines together and believe me I felt a big difference. And never had the rears lock up either. Just my .02 maybe it will help.
     
  9. chvyhs

    chvyhs 1/2 ton status

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    Do you know if I have this lever and valve on my '90? I haven't seen anything like that. Where exacly is it located?

    I think 35's might rub if you took it off road. If you're not planning on taking it off road I don't forsee any problems.
     
  10. Smurfmobile85

    Smurfmobile85 1/2 ton status

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    Maybe splicing them wouldn't be a bad idea. We can't seem to get them adjusted right. Thanks! /forums/images/icons/smile.gif

    Deana
     
  11. BanksBurban

    BanksBurban Registered Member

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    4" and 35's it is then. Can anyone recommend a good lift that uses HD rear springs capable of towing? I don't want to use blocks in the rear.
     
  12. JungleBoy

    JungleBoy 1/2 ton status

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    Someone may know of an aftermarket spring which will maintain your 2500s towing capacity - I do not. You may have to go with air bags, or some custom spring. What rpm are you running with 4.10s and the GV at 70?
    JB
     
  13. BanksBurban

    BanksBurban Registered Member

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    The tach doesn't work. I don't go over 65 cuz it sounds like it's gonna blow up LOL.
    And what good is high RPM's on a diesel anyway. That's why I want bigger tires, to bring it back to it's normal torque range at cruising speeds.
    The GV has a selector switch. It can engage at 20 MPH or 40 MPH. If I have it on 20 MPH, I can hit all four gears just driving around town.
    It's a great truck, but driving it like this sucks.
     
  14. tomseviltwin

    tomseviltwin 1/2 ton status

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    If you have this it is at the t where the main line connects to lines running to the wheels. The proportion valve is connected to the top of your axle housing and to the bottom of the body. Its a hinge like thing that folds when loaded. If you don't see it, you don't have it.
     
  15. FLASHLIGHT76

    FLASHLIGHT76 1/2 ton status

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    I'm sure this is a late post but I'll give it a go. I run 35's on 6 inches and as long as you leave the sway bar coneccted it's perfect. I'm still running the stock 3.73's and I run in the low 2000 to 2500 at 65 to 70 and that's with the 3 speed auto. As for the rear valve I pushed the lever up and disconected it from the axle and then removed the lever. When I order the extended brakelines I'll remove it completely. /forums/images/icons/smirk.gif
     

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