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Thread: Wheel Loader Problem

  1. Wheel Loader Problem

    Wheel Loader - Komatsu WA 500 - 6 - problem with tyres

    Hi, to everyone!

    Well, I have one problem and I can't conclude way it's happening.
    Let's start from beginning.
    Whell loader Komatsu WA 500 - 6 is woking in quarry and it's load dolomite raw material into dump tracks (granulation 0 - 400 mm).
    Type of tyres: 29.5R25 GP-4B AT OS 200B E4/L4 YL with chains on them. Right front tyre have small cracks at broadside. After thet we change position of font and back side of right tyre and it's happening again. Crack at broadside of tyre appears again. We check pressure every day and it's correct.

    Does everyone knows what happening?

    Thanx and best regards!
    Davor Antoljak, quarry engineer at Kamen Sirač, Croatia

  2. Tires my favorite subject-not




    Greetings and salutations from my corner of the
    frozen eastern wilderness@1140 feet above
    mean sea level.


    Please take note I have to go into great detail regarding this

    TO HELP YOU, and HELP ME TO HELP YOU as I am assuming

    you have a surface quarry-but the quick fix fix also works for room and pillar mining too.



    Have no fear you have a common problem which is

    serious and potentially fatal to a bystander but easily solved.


    At what time are you checking the tire pressures?


    The following information is very important because the tire pressure will vary

    widely during the operating day from the use of the tire.


    A few questions from me first:

    Are you using a solid tire/slick tread or a lug tire?

    are the tire pressures identical onn all four wheels or

    greater on the bogie end -boom and bucket end of the loader?


    The normal state of affairs is to have 10 KPA greater pressure

    on the bucket end of the machine.





    Assuming on my part you have a 5 piece Goodyear rim, or other

    tubeless rim base with a tapered side for your tires consisting of a wheel with a large bore

    with a welded lug nut ring attached to it but not centered in the wheel

    utilizing lug nuts to attach it to the mounting flange and driven by planetary axles:


    If you have tube type rim it is straight across with no slope and has a long machined slot for a tube and

    valve stem.

    ==========================================================================


    1. two side wall rings

    2. wheel

    3. tire sealing ring with o-ring groove

    4. tire locking ring

    5. wedge lock for tire split rim locking ring

    a. large bore tubeless tire valve stem with oring sealing.

    b. 3/8 inch metric equivalent O ring for sealing purposes if tubeless


    ===================================================


    As I do not know how many shifts per day you operate-

    The tires should be checked only when they are cold and

    ONLY then because this is the only time you wil have a

    a proper tire pressure- for many reasons including:



    The tire is a pressure vessel it becomes a "pressure vessel affected by heat" created by simple friction

    which will add air pressure and tire deflection from mucking-scooping, travel speed-tramming speed

    road surface condition stressing the tire tread and sidewalls.




    What you are dealing and have no physical control over is sidewall

    flexing of the tires and this happens for a number of reasons

    and of which is something I am very familiar with and is corrected by

    you and your tire supplier as a side wall blowout of a tire is

    powerfull enough to kill bystanders and not a good thing.


    (Also one of the many reasons I absolutely hate and detest

    tubeless mining and logging tires with o-ringseals as tube type tires

    are easier to maintain from my point of having installed and removed and

    repaired tires up 29.00- 26. 00 size and everthing smaller than that as part of

    my previous job on a daily basis).


    =========================================================================

    Solving the problem and the quick fixes


    1. Your use of the tire chains adds much life to

    your tires and that is great for your use.



    2. using smaller shot rounds to make smaller shot

    muck piles to allow the loader to scoop\rather than dig

    by shooting one line rather than multiple shot lines which

    in itself is easier on the machines tires but affects production-

    a smaller shot reduces the amount of ore brought down at

    one time and reduces the effort required to enter the pile to

    dig the material out to transport it to a crusher or haul truck.

    This is the quickest fix for you to see immediate results as

    less muck will be thrown and the operator should only have

    to scoop the rock- a bit more flyrock will be created but

    it will be much less weight to deal with as far as resistance

    because the actual created volume of material is less.


    a. resetting the loaders throttle high idle to 60 percent of actual engine high idle speed-

    this will be your easiest to implement solution if you intend to keep your shot rounds

    and tonnage the same size, and will be immediate in a solution to your problem.

    and physically locking the transmission to limit travel speed to one speed forward,

    one speed in reverse- you will see the quickest results with this method as

    one one forward speed will be used to enter the muck pile and exit it.

    and the engines net available torque will force the operator to

    slow down to prevent wheel slip and simply keep scooping until the

    bucket is nearly full- FYI you want a bucket load that is struck-level and

    not heaped whch makes it harder on the machine in any case.



    3. adding liquid calcium chloride ballast, will help with traction but

    the loader MUST be reduced to one speed forward and one in reverse

    which will totally solve the problem in either case as the tires will be

    able to add tractive effort (you do not want the tires to spin while digging)

    anyway and by then you have no traction because of the resistance by the shot

    limestone weight and actual mass.



    4. using the engine speed and travel spedd fixes are the ones with the quickest results for you.

    just be sure to check the tire pressures on a cold basis.


    Depending on the tire it may have 24 or more tread plies and 18 sidewall plies in its contruction

    in addition to wire stengthening reinforcement plies.




    Recapping.


    Locking out all but the first gear in forward and reverse and changing the engine high

    idle speed will show immediate results for you.


    Sidewall cracking is inevitable with machines employing planetary axles.


    Keep using the chains to protect the tires.





    lzaharis
    Last edited by lzaharis; 25th March 2010 at 16:46.

  3. Sounds like side walls of retreads cracking.

  4. tires

    for what its worth

    New tire side walls will do the same thing with mining/logging tire so its a common problem-see below.

    I have had loaders tear and break the bolts out of the bogie axle mounting/attaching plates due to no spin differentials and too much torque while mucking as the ground did not slip under the loader due to its being rock and the throttle was not limited

  5. Thank you Izaharis! Thanks to everybody, ofcourse!

    ...let's go to work and check all this parameters and if I concluded what happaned with tires, I'll post a reply.

    Best regards!
    Davor Antoljak, quarry engineer at Kamen Sirač, Croatia

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