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Gound Pressure?!

Discussion in 'Heavy Equipment & Pavement' started by TNdigger, Apr 14, 2008.

  1. TNdigger

    TNdigger LawnSite Member
    Posts: 10

    i am hopeing that some of you more experienced guys can help me understand this. The machines that I am lookng at have anywhere 3.5 up to 5.1 ground . The rep at the case dealership said that his low GP D6 dozer has 5.5. I need a machine that can handle heavy loads up and down hilly terrain. However I am a small company and frankly can not afford multiple Track loaders. The case is a beast of machine as far a specs go but being that I working a high end residential market I can not afford to have to replace every piece of turf I Drive across. So I gues my question is will there be a noticable difference in track depths (over sensitive ground) between machines of equal weights that have that a big difference in ground pressure difference (3.5-5.1). Thanks again for your time and knowledge.:confused:
  2. hansondirtman

    hansondirtman LawnSite Member
    Posts: 49

    In my experience even half a pound of ground pressure can make a huge difference. Think about it, 5.1 is 45% more than 3.5, that is a lot heavier on the ground. I would trust your instincts and get the lowest ground pressure you can.
  3. AWJ Services

    AWJ Services LawnSite Platinum Member
    from Ga
    Posts: 4,276

    The track lug design will cause more damage then the actual psi.
  4. dozerman21

    dozerman21 LawnSite Bronze Member
    Posts: 1,170

    On sensative or wet ground, 3.5 psi and 5.1 are noticeably different. I would demo whatever your considering and test it on a yard and see how it does. Something else to think about is soil type. Different parts of the country will have different ground, so what doesn't work one place might be o.k. somewhere else.
  5. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Posts: 10,101

    It also matters to how many times you make trips back and forth over the same path.
  6. Digdeep

    Digdeep LawnSite Bronze Member
    Posts: 1,840

    Good points. Weight distribution front to rear will also have an effect. Machines with more weight toward the rear will curl up the turf and soil more than a machine with a more even weight distribution.
  7. Bob Horrell

    Bob Horrell LawnSite Member
    Posts: 27

    An average adult footprint exerts about 7psi - a child is around 3 to 4psi. With this in mind you can see that the damage a machine does to the ground if it is anywhere less than say 7psi is going to be determined by factors other than ground pressure. Some of these factors are: grouser height, number of grousers, the type of soil, the moisture, any change in direction while traveling, the speed traveled, the amount of vibration of the soil by the machine etc. etc. A 7psi machine traveling in a straight line with medium size grousers on hard packet soil will leave very little evidence while a 3psi machine with worn out grousers on wet soft soil will make a heck of a mess. There are many factors other than psi that make a difference.

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