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What gears for 37" tires ???

Discussion in 'The Garage' started by Z3PR, Jan 23, 2003.

  1. Z3PR

    Z3PR Banned

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    What gears for 37\" tires ???

    Okay, I know gears have been talked about for 33" tires and 35" tires. But I'm going 37x12.50x15 tires. I've decided on 37" tires. Here's what I've got. 76 K5 with a 400cid small block backed by a TH350/NP-203. Planning on swaping in a NP-205 in the near future. Will be adding heavy duty tranny cooler. I need to be able to drive on the interstate for cross country road trips, and go wheeling in the forest (Very steep hills) So what gears would I need ???? I plan on doing the swap and Detroit Locker in the 14 Bolt FF befor I install the 3/4 Ton axles.
     
  2. Highlander

    Highlander 1/2 ton status

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    Re: What gears for 37\" tires ???

    Paul
    I would say 4.56 would be a good start.


    Eric
     
  3. TONYP

    TONYP 1/2 ton status

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    Re: What gears for 37\" tires ???

    I'd like to know too, I'm running 35's right now w/3.73 and on the freeway it runs great, when the 37/38 go on I'll have to see how thy run. I was thinking of running a doubler for the low end..... /forums/images/graemlins/k5.gif
     
  4. HarryH3

    HarryH3 1 ton status Author

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    Re: What gears for 37\" tires ???

    4.56's would be good with no overdrive. 5.13's would probably be a sweet spot with an overdrive tranny. /forums/images/graemlins/cool.gif
     
  5. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    Re: What gears for 37\" tires ???

    i would go with 4:56's i have 38's and 4:10's and its ok on the freeway but sucks offroad /forums/images/graemlins/frown.gif so im going to 5:13's but for you with 37's and lots of freeway driving i would say 4:56's
     
  6. oatsk5

    oatsk5 1/2 ton status Premium Member GMOTM Winner

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    Re: What gears for 37\" tires ???

    has everyone forgot the 4.88 a friend of mine has 37's on his furd and hes running 37 with a 5 speed trany he loves it he also pulls his heep with it /forums/images/graemlins/thumb.gif
     
  7. 90K5

    90K5 1/2 ton status

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    Re: What gears for 37\" tires ???

    you friend also has OD...4.56's should work well. it would be a lot like 3.73s and 33's or 4.11's and 35's
     
  8. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    Re: What gears for 37\" tires ???

    i have 36"s right now and a set of 4.56s sittin in my room waiting to be installed, i'm goin up to 37x12.50 SSRs next.
     
  9. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    Re: What gears for 37\" tires ???

    with overdrive yes i would go with 4:88's but he dont have overdrive your friend does /forums/images/graemlins/shocked.gif
     
  10. MudFrog

    MudFrog 1/2 ton status

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    Re: What gears for 37\" tires ???

    I've got 37's and 4.10's and it's not a very fun combination. The truck is pretty sluggish now. I would go with 4.88's if I could swap in a set of gears.
     
  11. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

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    Re: What gears for 37\" tires ???

    I have 4.88 's and 37" mtr's with a 700r-4 works great For me /forums/images/graemlins/truck.gif
     
  12. zakk

    zakk 1/2 ton status

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    Re: What gears for 37\" tires ???

    4.56's would be about 2750 RPM's
    4.88's would be about 2880 RPM's

    with a SBC400, they do not spin as high (unless they are REALLY built), so go with the 4.56's, IMHO

    *edit* all calculations assume 65 mph
     
  13. Blazinaire

    Blazinaire 1/2 ton status

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    Re: What gears for 37\" tires ???

    I know that everyone else has already said this, but I will have to agree: without OD 4.56's and 37''s are the way to go. I will soon be running 37''s with 4.56's, but I feel that it won't be enough gear for me to really use OD (I am running 4.56's and 35''s right now with a 700R4) But without OD it should be just right
     

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