Airing PUP Down

Discussion in 'Taking Your Camper Off Road' started by Shuswap, Feb 19, 2012.

  1. Shuswap

    Shuswap New Member

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    Just got our ntus Evo E1 and see the trailer tires call for 50 psi. The Explorer's 33's carry 35psi. When offroad I air down the truck to about 26 psi. Question is how much to air down the trailer tires?
     
  2. austinm48

    austinm48 http://s1174.photobucket.com/albums/r604/austinm48

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    you let the air down in the tires to widen the tires but i wouldn't lower pup at all so it has the better ground clearance
     
  3. papachaz

    papachaz New Member

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    yeah you're not needing more surface area for traction or turning, it's just being dragged along. i'd leave them be if it was me
     
  4. CIGARGUY

    CIGARGUY New Member

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    Totally agree. I used to offroad in several Wranglers years back. We always deflated tired so they conformed better to the terrain and proceeded a better grip, but the PUP doesn't have drive wheels. Deflating them would actually be counterproductive by making it harder to pull.
     
  5. mgeiger

    mgeiger New Member

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    Congrats on the E1, my dream pup. Airing the trailer down does smooth the ride a little, to reduce the shock and vibration. If it's slick(mud or snow), a little bigger contact patch would not hurt in keeping it tracking straight.
     
  6. Shuswap

    Shuswap New Member

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    I should have mentioned that, in our experience, the main issue offroad is washboard and loose rock. I would have thought that airing down the pup ries some would reduce the vibration over the washboard.
     
  7. electronflux

    electronflux Member

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    an excerpt from tire rack.com:

    "An underinflated tire can't maintain its shape and becomes flatter than intended while in contact with the road. If a vehicle’s tires are underinflated by only 6 psi it could lead to tire failure. Additionally, the tire’s tread life could be reduced by as much as 25%. Lower inflation pressure will allow the tire to deflect (bend) more as it rolls. This will build up internal heat, increase rolling resistance and cause a reduction in fuel economy of up to 5%. You would experience a significant loss of steering precision and cornering stability. While 6 psi doesn’t seem excessively low, remember, it usually represents about 20% of the tire’s recommended pressure."
     
  8. CIGARGUY

    CIGARGUY New Member

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    This information absolutely holds true when it comes to onroad, everyday driving. Under inflation is the quickest way to destroy a tire. In the OP's situation, deflating the tires somewhat is common practice, and the above information doesn't really apply. When offroading, you're usually at a creeping rate of speed, and you're tires aren't in contact with a paved surface so abnormal wear is at a minimum.
     
  9. electronflux

    electronflux Member

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    notice there weren't any exceptions listed for going off road.

    Just because you say that it's common practice doesn't mean it's a smart practice. It's been disproved on mythbusters that under inflating your tires gives you better traction. they did it on dry/wet/icy pavement and dirt.
     
  10. Twisty

    Twisty New Member

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    I don't think that bias trailer tires are intended to flex at all. The springs are the suspension and installing softer ones would help.
    Consider running radials and airing them down.
     
  11. CIGARGUY

    CIGARGUY New Member

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    There aren't any exceptions for offroad because only a fraction of tires sold actually get used offroad. I participate(d) in some high adrenaline activities that many would consider dangerous (offroading, road rallies on mountain highways, skydiving). I can assure you that people who do participate in these type things are far safer in their practices than the majority of people who don't. We realize that we are flirting with disaster each time we participate so we double and triple check our equipment and safety precautions. Just because you deem it to be "not smart practice" doesn't necessarily make it so. If mythbusters didn't test this theory on rock crawling, there really isn't an argument to be made here. I have seen and experienced it firsthand, and anyone who enjoys the sport of rock crawling will agree, slight deflation does improve your rig's capability. We travel at speeds that are so low they wouldn't register on a speedometer. How, exactly, could an under inflated tire be dangerous in this scenario?
     
  12. Twisty

    Twisty New Member

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    Apples and Oranges my friends.
     
  13. electronflux

    electronflux Member

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    what does rock crawling have to do with pup towing?
     
  14. Twisty

    Twisty New Member

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    Horses and Oxen my friends.
     
  15. bearman512

    bearman512 Well-Known Member

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    I'm with you Cigarguy, and I am waiting for this to get heated and then I will add my [2C].
    Been running washboard roads forever and when I do head up my secret camping trails I lower the psi in my pup tires.
    1 caveat though, I have 15" mud terrains on mine and can lower the psi to 25 which keeps the sharp rocks from puncturing sidewalls. I would rather reseat the bead than tear a hole in the sidewall. Around here in NM we do have signs warning you to ether air-down or risk cuts in your tires.
     
  16. CIGARGUY

    CIGARGUY New Member

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    A broken bead is no match for a can of carb cleaner and a lighter, right? [:D]

    I'm leaving this thread alone. I think in some cases it's better to agree to disagree. We all have practices that others think are crazy whether they're dangerous or not.
     
  17. bearman512

    bearman512 Well-Known Member

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    AGREE Keep on Rockin my brother.
     
  18. Shuswap

    Shuswap New Member

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    I found this in an ARB blog http://arbusa.wordpress.com/2011/10/26/the-lowdown-off-road-tire-pressures/

    "Lower tire pressures (but not as low as for slow rock crawling) can also be of benefit when driving on faster gravel or dirt roads by allowing the tread to conform to the individual stones or sharp protrusions to help prevent puncturing. Remember to keep in mind that the lower your pressure are set, the lower your speeds should be."

    That article also describes how to determine how much to air down the trailer tire.
     
  19. CIGARGUY

    CIGARGUY New Member

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    Nice find! Honestly, I wouldn't have thought it would make sense to deflate trailer tires, but it just goes to prove that I never have it all figured out. Theres always something to learn.
     
  20. zjrog

    zjrog Member

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    Very common to reduce tire pressure in sand and soft surfaces. For rock crawling you want the tires to conform to the rock face. On desert washboard, lower tire pressure preserves equipment and makes for a smoother ride. I do this myself frequently.
    [​IMG]

    Which is why I want to put bigger tires on my own Pup. A margin of comfort and safety.
     

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