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Can you use a smaller spare tire if you have a open differential?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by shum1, Dec 12, 2000.

  1. shum1

    shum1 1/2 ton status

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    I'm gonna get 35's but they dont fit in the stock spare location in my suburban. Can I get by w/ a 31" spare on the highway if I have open differntials? Will this hurt anything? Thanks
     
  2. TX Mudder

    TX Mudder 1/2 ton status

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    I wouldn't drive it on the highway like that.
    If you had a flat and had to drive it home at about 35 it seems lie it would be OK - let air out of the other tire on the same axle as the 31 to help it a little.
    And, have both 35's on the front (more important.)
    -- Mike
     
  3. BigJim85

    BigJim85 1/2 ton status

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    Heh, my friend runs 35's on his Bronc. He has his old left over bald 31 on his spare carrier. He hasn't fouled up yet, but I'll keep ya posted on how it rides when he does.

    <font color=red>If it's stupid but works, it isn't stupid.</font color=red>
     
  4. HarryH3

    HarryH3 1 ton status Author

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    You don't want to go far or fast with that configuration. The spider gears just ride on a thrust washer, not real bearings. They are designed to just rotate a little bit, from time to time. I don't think that they'd be very happy if you kept them spinning continously, which is exactly what they'd be doing with two differrent size tires. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  5. Executioner

    Executioner 1/2 ton status

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    How do you know you have an open diff. ?
    Sometimes a limited slip/possi will act like an open diff.
    Even a GM Eaton Gov-Lok, can act like an open diff.
    If you really what to drive on the freeway, please be carfull !
    If you can put both same o.d. tires on the front, and make sure the hubs are unlocked,
    if full-time four wheel drive, see if you can remove the front driveshaft.
    In the rear lower the air pressure in the larger tire, and increase the pressure in the smaller tire.
    Good luck
     
  6. shum1

    shum1 1/2 ton status

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    Thanks for the advise. I'm assuming that my diff is open because the code is not listed on the glovebox and the one owner before me didnt mention it, although the did say it had been rebuilt.
     
  7. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Running a different size spare shouldn't hurt anything if you just run it long enough to get to a tire shop. Also, make sure to reduce your speed because the different sized tires can cause some weird handling. It's pretty common for vehicles to come stock with smaller sized spares........
     
  8. ftn96

    ftn96 1/2 ton status

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    Wait a minute. If your on the Highway, the only gears that will be turning will be the rear, right? Wouldn't you want to put the tires of the same diameter on the rear? The front is not geared at this time so only the tires will be turning, not the differential. Yes the steering and handling issue then arises, but go slower and get to were you can fix the tire. But to save the gears, if that is the issue, put the same size tires on the axle thats being used.

    I miss my Ex, but my aim is getting better!
    http://mccordhouse.freeservers.com
     
  9. 6.2Blazer

    6.2Blazer 1/2 ton status

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    In my opinion, I wouldn't bother swapping tires back and forth to put the smaller spare in a particular location.....if a rear tire went flat put the spare on the rear, if a front tire went flat put the spare on the front. I don't think the wear on the rear end would be an issue unless someone decided to run thousands of miles with different size tires.
     
  10. ftn96

    ftn96 1/2 ton status

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  11. jmpd

    jmpd 1/2 ton status

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    I had to run a tire off my buddy's 1970 2 wheel drive Chevy Truck from Rocky Point Mexico, back to Mesa, AZ. the tire size was a stock 70 or something like that. I had 31" tires, 3:73 open rearend at that time(10Bolt). I put the tire on the drivers side rear. I drove home at about 60mph for about 200 or so miles, with 4 guys and gear. My spare had separated the day we left for Mexico. This was back in my college spring break days when money was something I had very little of.

    P.S. I think this help contribute to my spider gears exploding a couple of years later on the POS 10bolt

    Michael
     

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