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axle wrap

Discussion in 'The Garage' started by smp92xj, May 13, 2003.

  1. smp92xj

    smp92xj Registered Member

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    I am having problems with axle wrap, mostly on decel. I've got a 2.5 shackle flip, FF 14b, 35" goodyears and stock springs. Any ideas that would not limit travel or change the ride?
    thanks, sean
     
  2. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Axle wrap happens on acceleration, not deceleration. Describe the problem that you're having, since it's not axle wrap... </font>
     
  3. NE-RokToy

    NE-RokToy Registered Member

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    [ QUOTE ]
    <font color="green"> Axle wrap happens on acceleration, not deceleration. Describe the problem that you're having, since it's not axle wrap... </font>

    [/ QUOTE ]


    OK do a test for me go jump in your truck get up to about 50 MPH and slam on your brakes as hard as possible. Go out and look at the tracks left, most pickups will have axle wrap and wheel hop under accelerating and decelerating as these are the same forces acting on the springs just in oposite directions.

    The best bet to rid a leaf spring setup of wrap is a ladder bar style traction bar mounted with a shackle at the crossmember end. It will make your vehicle much more stable/predictable braking and accelerating, and it will wheel alot better too.
     
  4. morphed86k10

    morphed86k10 1/2 ton status

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    [ QUOTE ]
    Axle wrap happens on acceleration, not deceleration.

    [/ QUOTE ]
    No, its just more common for people to notice on decelleration. I believe Rene had a problem with axle wrap under decelleration after going to the 57" ford springs before the a-tron bar was tossed in.
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Yes I had wicked axle wrap under deceleration, the closer to lock-up the worse it got. If the rear tires started to lock they would start bouncing violently.../forums/images/graemlins/eek.gif

    I agree that axle wrap is much easier to notice under braking...especially if you have a 6.2 /forums/images/graemlins/grin.gif

    The A-tron bar absolutely killed my axle wrap problem though. I've had to make a panic stop once so far since installing it and it was very controllable and predictable with no tire hop whatsoever.

    Rene
     
  6. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> I've never had that problem, maybe because I have a pickup so it's just too light in the back to have any problems like that. It just doesn't seem like it would be that easy to induce under braking. Live and learn... /forums/images/graemlins/1zhelp.gif</font>
     
  7. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    It's actually easier under braking, all things being equal (but they aren’t). To get axle wrap on acceleration, you have to have enough power combined with traction to twist the springs while overcoming inertia before the tire slips to produce the hop. Also, many trucks (GM with 56” springs for instance) have an offset spring with the short side in front to combat acceleration induced axel wrap. For axle wrap on deceleration you have the similar forces at work (thought kinetically different) except you now have the braking power rather than engine power trying to twist the springs, plus you have the long side being bent up rather than the short side. The difference is that under braking you transfer weight to the front of the vehicle reducing the rear tires traction so that it usually slips before it can twist far enough to “hop” after slipping. Over simplified but that is the gist of things as I understand it...
     
  8. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> I understand the physics of it, I just never thought that it was a problem in the real world. I guess with the super soft springs that everyone runs now it probably happens alot more often. </font>
     
  9. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Yeah, my reversed 57s are so bad with 42s they hop both ways on a dirt road. /forums/images/graemlins/crazy.gif
     
  10. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    I have it really bad on acceleration but not really on deceleration, its more when I down shift going sorta fast, then the whole things jumps around, not when I slam on the brakes.
     
  11. Blazinaire

    Blazinaire 1/2 ton status

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    soon after I put my 57''s in I noticed that when rapidly slowing down from 70 mph (freeway offramp) the truck would hop around rather violently. It is actually much worse than the wrap that I get when accelerating hard. So would an anti wrap bar help with the deceleration axle wrap?
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    [ QUOTE ]
    So would an anti wrap bar help with the deceleration axle wrap?

    [/ QUOTE ]

    Yes, the A-tron bar eliminated that same problem on my truck. Even locked up in the rear the tires do not bounce or anything now. Without the bar as I got to the threshold of lock-up the rear tires would begin to violently hop up and down...sure made stopping distance grow to an unsafe level! The difference after the bar was installed is night and day!!/forums/images/graemlins/thumb.gif

    Rene
     

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