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33" tires on a 2.5ltr YJ or not?

Discussion in 'Wheels & Tires' started by GUARDDOGG, Jul 9, 2017.

  1. Jul 9, 2017 at 12:04 PM
    #1
    GUARDDOGG

    GUARDDOGG [OP] Member

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    So I bought a 1994 Jeep YJ with a 2.5 ltr 4 cylinder I rebuilt & lifted (RC 4.5") I want 33" tires I have 4.11 gears & a 5 speed trans.
    I figure I'm going to want to re-gear to a 4.56 ASAP but what can I expect for a top speed on the highway & RPMs from my creation?

    This is my very first Jeep I drove it home the day I bought it, 20 highway miles on 31" tires & seemed fine for a 4cyl vehicle. Got it home & tore it apart & i'm about to put it on the road but want bigger tires.

    Please advise guys. I know a 4cyl is not the most ideal motor but that's what I'm working with.
     
  2. Jul 9, 2017 at 6:53 PM
    #2
    JKBob 25

    JKBob 25 Well-Known Member

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    Subbed. I'm curious too. Good luck with it Dan.
     
    GUARDDOGG [OP] likes this.
  3. Jul 11, 2017 at 7:39 AM
    #3
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    New tire size (33) X the old gear ratio (4.10) / the old tire size (?) will give you the gear ratio you should run to maintain factory specs. I always round up. The next available gear ratio.
     
    JKBob 25 likes this.
  4. Jul 11, 2017 at 7:44 AM
    #4
    OFFGRID

    OFFGRID Well-Known Member

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    Houston
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    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    If you had a 29 factory wheel that would look like this.

    33 x 4.10 / 29 = 4.6655172414

    Round up to 4.88 gears.
     
    JKBob 25 and aggrex like this.
  5. Jul 13, 2017 at 10:59 AM
    #5
    GUARDDOGG

    GUARDDOGG [OP] Member

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    Ground up rebuilding
    Cool, don't think it matters much but my rear end gearing is 4.11 and the front is 4.10.
    So with 4.88 or even 4.56 gears what would you say would be my Top speed would be on the highway?
    I'm sure somebody has or has had this combination on their Jeep & knows it off hand.
    Thanks for the help OffGrid.
     
  6. Jul 13, 2017 at 12:00 PM
    #6
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Do you know the gear ratio of your Top Gear?
     
  7. Jul 13, 2017 at 8:07 PM
    #7
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    You should be able to do the same speed you are doing now with stock gear ratio and stock tires. That is why the math equation is used. You run into trouble when you start going really big on a 4cyl like 37s and up. You might suffer a little with 35s, but the 33s will do fine.
     
    chris4x4 likes this.
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