Pusher lift axle pressure

Discussion in 'Heavy Haul Trucking Forum' started by macmanboomer, Jan 17, 2020.

  1. macmanboomer

    macmanboomer Light Load Member

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    Oct 19, 2014
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    I just added a new pusher lift axle & working on figuring out my regulated air supply pressure to get weights matched with drives which takes time & experimenting.

    Question is why not have the drive axle air bag supply feed air to the controls for the lift axle so that it automatically provides even pressure across all 3 axles? When you drop your suspension it would drop all 3 axles & you could still lift the pusher by itself as well. My flip axle on the trailer is set up that way. Is there a reason not to do it on the front tri like that?
     
  2. Roberts450

    Roberts450 Road Train Member

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    It all depends on the axle and tire rating of the lift axle. If you’re running a 20-22k lift spaced close to the drive’s and can run 20k across all 3 and the air bags are ruffly the same size, then I dont see why you couldn’t have it setup to run “suspension” pressure. I have a 13k steerable lift on my truck and only allowed 11k per the tire rating and my 3 axle group is only rated for 45k so I generally run enough pressure in it to put right around 10k on it.
     
  3. macmanboomer

    macmanboomer Light Load Member

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    Oct 19, 2014
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    Yes, sorry I forgot to specify.

    20k pusher, same spacing as the tandems. Normally permitted at 60k or 55k on tridem.
     
  4. Arch Stanton

    Arch Stanton Bobtail Member

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    May 5, 2019
    San Diego
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    you need to look up your specific Axel and ride height on my Watson Chalin they give pressure for load based on ride height and to run the same pressure on drives and drop axel the bags would have to be the same diameter and same suspension. also on my drop Axel the lift bags and load bags run of the same regulator if I ran my lift bags at the 15 pounds my rear suspension runs when I'm empty the lift Axel bounces up and down because 15 psi in not enough to keep the lift Axel tight to the frame
     
  5. macmanboomer

    macmanboomer Light Load Member

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    Oct 19, 2014
    TN
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    Good point about not enough pressure to lift. I think you could work around that with 2 separate valves though.
     
  6. beastr123

    beastr123 Road Train Member

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    Moose Jaw SK CAN
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    if your bags are equal diameter then it is possible to use an automated system such as: Automatic Lift Axle Control | Today's Trucking
    or something similar. they are mandated as the only legal way to lift axles on trailers in Western Canada (by annual permit) and lifts are still outlawed on tractors with some special exceptions.
    10 or 15 years ago I used to get calls 2 or 3 times a year to go to Estevan SK scales to transload a piece of equipment for a US hauler who ran afoul of Canadian laws. The most common was long wheelbased tractors and lift axles on tractors. We had a short jump-jeep that could pin a 86 inch swing and just make legal weights at 54000# (34000 drives and 20000 jeep). That jeep let me take his loaded trailer to deliver and return saving crane time on no wheel loads.
     
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