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3.42's with what size tire???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by XHitman396, Nov 20, 2002.

  1. XHitman396

    XHitman396 1/2 ton status

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    3.42\'s with what size tire???

    i WANTED to go 35's, but will the 3.42's, stock 350 and 700r4 be able to handle that without total loss of power, no rocks, just mud?? thanks in advance
     
  2. BLUESMAN

    BLUESMAN 1/2 ton status

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    Re: 3.42\'s with what size tire???

    Two words...NO WAY!!I think you might be bordering on running 32's.At least 4.10's with that 700 and 35" tires.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: 3.42\'s with what size tire???

    I've got 3.42's with my 33's, but I've got the SM465. If I had overdrive, I would have at LEAST 3.73's, if not 4.10's.

    3.42's and the 35's would be as bad as 3.08's and 33's I bet.
     
  4. K5thatShmobs

    K5thatShmobs 1/2 ton status

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    Re: 3.42\'s with what size tire???

    Even though 3.42s are a little shallow for the likes of 35s, youre still at as much of an advantage as possible on all other fronts. You have a 700R4 with a 3.06:1 first gear and an np208 with a 2.72:1 low range ratio. Gearing wise, that tranny/t-case combination is the lowest on a K5. My first blazer had the same tranny/t-case combo youre running with 3.07:1 in the diffs, and I was running 35" boggers. I did ok... I never noticed any impairing power issues, however, if I had the cash back then, I would have gone at least 4.10:1 in a second. 4.56 would probably work for you too, because you have overdrive with a mere .7:1 ratio in 4th gear.
     
  5. Lance

    Lance 1/2 ton status

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    Re: 3.42\'s with what size tire???

    If you don't use OD you should be fine. I had 33" w/ 3.42's and although I didn't notice any real power issues, at cruising speeds with the truck in OD, I would be too far below the desired power band. That is a real good way to smoke a tranny.
     
  6. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    Re: 3.42\'s with what size tire???

    I have 33's with 3.42s. It does fine around town. From what im readin here I guess I should consider changin some gears before I start goin to college next year. From what yall are sayin 700R4, 33s, 3.42s and OD on highway (throw in mountains on the way) and my tranny would be toast. Should I go 4.10s or will 3.73s do. /forums/images/graemlins/1zhelp.gif
     
  7. WakeBoard&4X4er

    WakeBoard&4X4er 1/2 ton status

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    Re: 3.42\'s with what size tire???

    i have 35s and 3.42, and pull a boat, and wheel, and use od all the time, and have had no problems, however i have a Big tranny cooler, and Tran temp gauge, watch the temp all the time.
     
  8. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    Re: 3.42\'s with what size tire???

    I do have a tranny cooler but no trans temp gauge. Maybe I should look into that /forums/images/graemlins/ears.gif
     
  9. milspecjimmy

    milspecjimmy 1/2 ton status

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    Re: 3.42\'s with what size tire???

    i have 3.42's on my jimmy, and its a little doggy on the hills, but fine for every thing i want to do with it for now. i will be putting in 4.56's when i swap to 60's.
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
     
  10. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: 3.42\'s with what size tire???

    35's and a 700 I'd be concidering 4.56 to take the load off the tranny and keep it from hunting in and out of OD.
    I'm not sure I would put that ig of a tire on with out 4.10's atleast. With OD that will put the engine in the sweet spot on the hwy.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: 3.42\'s with what size tire???

    Only a couple of things, and slightly off topic, the 465/205 combo with 3.42's is a 44:1 crawl ratio, the 700/208 is only 28:1.

    35" tires installed after 31" tires with a 3.42 axle ratio equals an effective gear ratio of 3.03. 33" tires vs 31" tires with 3.08 axle ratio equals an effective ratio of 2.89. Those effective numbers are darn close, (33 with 3.08's vs 35's with 3.42's) and I don't think anyone would agree that 33's and 3.08's even with a 700 are a match made in heaven.

    But anyway, thats just my opinion. If you've got a strong motor, gear ratio won't mean quite as much, but with a 305, 700/208 and 3.08's, even with 31's, my former K5 was a dog.
     
  12. XHitman396

    XHitman396 1/2 ton status

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    Re: 3.42\'s with what size tire???

    ok since this was a pretty one-sided reply, now the big question, how much does it cost/how hard is it to swap over to 4.10's, i can't afford much, and have never taken a diff apart before either, thanks
     
  13. BurbLover

    BurbLover 1/2 ton status

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    Re: 3.42\'s with what size tire???

    I ran my 3.42s with 33s for almost 2 years. I seldom went off-rioad. I mainly did highway driving. For that, they worked very well. However, I was running 90 most of the time from Cheyenne to Colorado Springs. Not much in the middle. I would agree this is not the best combo, but my 350/700R4/208 w/ 3.42s worked just fine. I's say determine your requirements & see what will work. If it is $$, do what momma says you can afford!!!
    /forums/images/graemlins/burb.gif
     
  14. MA87K5

    MA87K5 1/2 ton status

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    Re: 3.42\'s with what size tire???

    I was told by a local rearend shop that it would cost me $750 to replace my rear gears. I looked at my rear and found that the internal gears and shaft were worn. So that gave me the perfect excuse to get a posi. I installed it myself and got lucky with the carrier shims. Didn't need to touch the pinion. Took my time and it took me a weekend. That was almost a month ago and no problems with it. I'm very happy. Sorry to ramble. I think most rearend shops charge $75 per hour. I have 3.42 rear and 33" tires with 340/700r4, and when I went muddin I had no problem going through. I had the power to do it and my engine has 178k miles on it. The only things that was upgraded was the exhaust to 3" and a K&N filter. It is pretty quick for a 4500lb+ truck. It used to take me 45 min to get to work on the highway. Shifted into od at around 60mph and never had a problem with gas or wear. I watched the gas guage start to move 75mph and higher. Now I have a much closer job and I don't have to worry about gas anymore. Well not as much. I wouldn't go any taller then 33" tires with 3.42 though. I have front and rear 3.73 10blt sitting in my garage that I was thinking of installing but the gain would not outway the work of installing. And around here no one wants 3.73. To end this, Coloradok5 site it the best site for any kind of info for the K5 blazer.
     

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