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Tire pressure - how low can you go?

Discussion in '80-Series Tech' started by LINUS, Nov 20, 2003.

  1. LINUS

    LINUS Waiting for the Great Pumpkin

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    Maybe not 80/100 specific, but what's a realistic PSI that won't run a sidewall off a bead under light 'use' ?

    Reason I ask is that my truck is more a snow queen than any kind of rockcrawlin/mudboggin type rig, and airing down might be a reasonable solution on the drive home from the mountains under certain conditions (like a lack of chains in the back and lockers still on the shelf in the garage), so mainly we're talking about easy driving on snow covered roads/backroads.

    Or would the gain in traction be so small that it wouldn't be worth the time to air down? --Goodyear MT-R's FWIW--

    Total truth be told, I want to go snowboard this weekend (Mount Baker) and I haven't gotten a set of chains yet and I'm looking for any little advantage I can gain if I need it.
     
  2. DanKunz

    DanKunz SILVER Star

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    80s be heavy...I wouldn't go less than 15 for heavy offroad.

    I usually run 18 in the rear if I am loaded down for a run and 15 up front.

    If no load....15ish all around.

    For snow, etc...I dunno...doesn't snow here. If you plan on carrying any speed I would keep the pressure higher.
     
  3. moralien

    moralien

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    Just air down until you see a nice little buldge. I would not dip below 15.
     
  4. woody

    woody unhelpful spotter Staff Member Admin

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    unfortunately, it depends on a pile of variables....the tire itself, the rim, the rig weight, speed, etc. I know guys with 33" Swamper SX's that lose beads at 15 psi, yet I could run my 38.5" SX's at 5 and never lose one.

    Airing down even some will help in deeper snow. 15 sounds like a safe number. I've gone as low as 8 on radials and 3 on bias tires with no beadlocks and have never lost one. (~4000# rig tho...)
     
  5. MTNRAT

    MTNRAT SILVER Star

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    I would be reluctant to air down much for use snow covered roads. The extra sway from an airdowned tire may actually induce swaying and put you in the ditch. My first choice would be some ice radials, but if your pocketbook cannot take the hit, have the centre lugs of your MTRs siped. I siped mine and they work better than the stock MTRs.
    Sean
     
  6. cary

    cary

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    The general rule for driving on snow covered roads is that you want the smallest footprint so the tire will dig down and sit on a solid surface. If you are driving on roads with less than 1-1.5 ft of snow, you want to keep the tires aired up (notice the guys that live in snow country usually run skinnier tires). It is only when you are in deep snow that you want wide aired down tires, the idea being if the snow is 2-5 feet deep, you want to float on the top, not sink in.

    If you live in an areas that has a great deal of snow in the winter, consider real snow tires like Bizzacks, Pirelli W210s, Yokohama Gardex, Michelin Alpins. True snow tires will provide far better handling on snow covered roads and ice than any A/T or MT tire.

    Cary
     
  7. Bradass80

    Bradass80

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    I went to 8" wide wheels for this exact reason, i wanted to safely drop to 10psi, i like to drive in some deep snow when i can, 3' and deeper, i haven't lost a bead yet, 92 80 series on 37" MTRs, Brad.
     
  8. Junk

    Junk

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    Linus,
    First dude, you :flipoff2: for going to Baker. Wish I was there right now. That's my favorite spot in the whole frickin country.

    Airing down totally depends on the tire. For snow, you could go lower without destroying your rim than you could on the rocks. Just take it easy though and don't go too far unless you have a way to air back up. Driving on aired down tires at even backroad speed blows. So take it easy, and just kind of go with the flow.

    I've aired down bfg at/ko's last winter when in the snow down to 12 psi no problem, but I have a CO2 tank, so could always air back up no biggie. I've gone to 3 psi with swampers, but had to air up because it was just too low for heavy truck and I would have destroyed the rims.

    So the answer? There is no clear answer. Just air down, till you see a bulge. Go a little more, slowly, and go from there. It's easier to stop and let more out than it is to put more back in.

    :flipoff2: :D
     
  9. Hltoppr

    Hltoppr

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    Brad,

    Did you regear, or is your top speed now 35mph! ;)

    I prefer skinny tires aired up for snow that is up to 1-1.5 feet deep. Sucks in loose sand though...

    -H-
     
  10. Bradass80

    Bradass80

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    Yeah, it's got 5:29 gears in it and with that turbo Ben put on it'll go just about fast as you want it to, now if it would quit being 70 degrees in Colorado maybe we could get some snow to go and play in, Brad. :D
     
  11. nakman

    nakman addict. Supporting Vendor

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    IMO, you are nuts to use lockers in snow, particularly on actual roads with other cars around. They're fun for spinning, and will get you unstuck in some situations (can get you more stuck too) but a death wish on an icy or snowy paved road. CDL is a differerent story, but you knew that...