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35" tires what gears would be best?

Discussion in '1982-Present GM Diesel' started by surg82k5, Aug 27, 2001.

  1. surg82k5

    surg82k5 1/2 ton status

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    35\" tires what gears would be best?

    I have an '82 blazer with a 6.2, i added a 4" lift and 35". my question is what gears should i use I have heard people recommend 4.56 with OD or 4.10 without, I don't have OD at the moment but will drop in a 700 eventually, are these recommendations ok for my 6.2 or are the best just for gas engines. thanks
    sergio

    Check out my new website. <a target="_blank" href=http://www.surg82k5.rockcrawler.com>http://www.surg82k5.rockcrawler.com</a>
     
  2. surg82k5

    surg82k5 1/2 ton status

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    Re: 35\" tires what gears would be best?

    Anyone please...I am really curious to find out, Thanks
    sergio

    Check out my new website. <a target="_blank" href=http://www.surg82k5.rockcrawler.com>http://www.surg82k5.rockcrawler.com</a>
     
  3. JORGE

    JORGE 1/2 ton status

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    VITORIA-GAZTEIZ(ALAVA)BASQUE COUNTRY,SPAIN
    Re: 35

    I don,t know very much about the chevy diffs,here in Spain are not usuals.I have an 88´with 33x12.50 and i thinking,maybe i must to change to lower ratio too.However look at www.differentials.com in the FAQ.I think they have information about the ratios you need when you have high tire sizes.
    However this is the formula for the ideal MPH/RPM
    RPM=Gear ratio x Over Drive* x MPH x336 / Tire Diameter
    * Overdrive manual= .8
    Overdrive automatic=.7
    I hope to help to you.
     
  4. DieselDan

    DieselDan 1/2 ton status

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    Re: 35

    The 4.56/4.10 recommendation is pretty valid. I have a '89 6.2 with 700R trans. The D60/14FF hold 4.56 and turn 35" BFGs. The OD tranny really drops RPMs so it doesn't pull steep grades in OD very well. I plan on swapping in a manual SM465 trans sometime. That will keep my "comfortable" highway speed at about 65MPH, max. Then I'll have a good excuse to step up to 37" or 38" rubber!

    My recommdation for a non-OD trans is 4.10 if you do alot of highspeed/highway driving, 4.56 if you're willing to slow down just a little. And at least a 4.56 for the OD transmissions.

    Real trucks don't have spark plugs!<P ID="edit"><FONT class="small">Edited by DieselDan on 09/01/01 07:55 PM.</FONT></P>
     
  5. Kennedy

    Kennedy Registered Member

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    Re: 35

    What kind of fuel economy do you get with 4.56 gears and 35s- with, or without overdrive?
    I have a set of 5.13s that I might run with 37s and the TH700R4 but I am a little scared of the fuel consumption/RPM. Would 4.88s be better?

    What do you think?

    David
    1982 6.2L K-5
    2000 Silverado 2500
     
  6. DieselDan

    DieselDan 1/2 ton status

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    Re: 35

    I get 20+ MPG always during my daily commute that consists of some in town, alot of two lane, and some highway. Yes I would think 5.13 might be a little (too) much. 4.88 might be alittle too much also if plan on commuting in it. Diesels aren't real found of big RPMs. Just for though CUCV M1008 (K30) uses a TH400, 4.56 and 31" rubber; it just screams at 65 MPH. Fine for off road but could be tiresome for highway duty.

    Real trucks don't have spark plugs!
     
  7. BigDiesel

    BigDiesel Registered Member Premium Member

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    Re: 35

    Take a look at www.4lo.com. At the top is a gear calculator. Input all but the rpm and it will tell you what RPM you will spin with any given gear ratio.

    99 3500 dodge cummins, blah, blah, blah
    soon to have: 90-91 blazer or jimmy with 6.2
    I love the smell of diesel in the morning. (no,not really;))
     

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