1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Pit Bull Trailer Restraint

Discussion in 'General' started by Cuddles de Sade, Sep 15, 2007.

  1. thepro8

    thepro8 Well-Known Member

    I hate you.
     
  2. Cuddles de Sade

    Cuddles de Sade AnACREE in the UK!!!

    damn Rick, yours was funny until...
     
  3. thepro8

    thepro8 Well-Known Member

    Just called Pit bull about this since I'm very interested. Here are the key takeaways. Hopefully I got things right, if not, oh well :)

    -Site is going to be updated soon with new pin kits for more bikes
    -Will have a 05-06 will have a pin kit in about 2 weeks (good for me)
    -Will be adding a brace to the inside of the trailer restraint for extra support (the goal is to make your trailer be able to "withstand a slow speed impact by a semi and not have your bike come off the floor if your trailer is flipped")
    -no issue side to side pressure on the swingarm. will not damage the bike
    -currently hold at least 1100lbs of side to side pressure (basically your floor board will come apart as a failure)
    -You need no extra restraints

    Only issue people have mentions is they don't like that the front wheel can turn. This won't cause an issue, but pit bull recommends tightening your damper if you got one to keep this from happening.
     
  4. thepro8

    thepro8 Well-Known Member

    The only thing I am wondering his by locking the bike into a vertical position by the rear wheel, when taking turns in your car the side force (or in statics is called a moment) will be put on the swingarm joint. How will this join react over time?
     
  5. frackadelic

    frackadelic Buddha Stalin is Chronic

    Oh money, where art thou :(
     
  6. G 97

    G 97 Garth

    :stupid:
     
  7. G 97

    G 97 Garth

    :stupid:
     
  8. KrashBandit

    KrashBandit The other guy at Pit Bull

    By locking the rear wheel into an upright position with minimal room for swaying back and forth, you prevent the bike from gaining momentum swaying side to side. Force is defined as the rate of change of momentum. If the momentum never increases, then there is no increase in force which means there should be no unreasonable force applied to any part of your motorcycle. By holding the bike rigid, you limit the rate of change of momentum.
     
  9. thepro8

    thepro8 Well-Known Member

    Krash, moments are stationary. It's different from momentum. basically what's going to happen if you lock the bike into place like the pitbull restraint does and keep side forces, if the bike does not move there is pressure placed on the bike and some of the force is transfered into the trailer. This is no big deal most places, but I'm not sure about the rotational force on the joint where the swingarm attaches to the bike. That joint was made to take vertical movement, and the momentum that will happen to the bike on the trailer restraint is a rotational force or moment. The issue is, will this rotational force cause damage to that joint over time.

    -Former ME here sorry for the dork content. Want to give me a job :) ?
     
    Last edited: Sep 27, 2007
  10. Chip

    Chip Registered

    The swingarm pivot location is only designed to take vertical movement?
     
  11. KrashBandit

    KrashBandit The other guy at Pit Bull

    I would say the easiest answer would be to ask Chip, lol. He's had this version and a previous version in his trailer for quite some time now. Chip knows all.:bow:
     
  12. thepro8

    thepro8 Well-Known Member

    Correct me if I'm wrong (may very well be), but the swingarm only goes up and down. It is held together by a bold which means there is any "play" for it to rotate.
     
  13. Chip

    Chip Registered

    Chip's an idtio....but Chip and company can break ANYTHING and we can't break the Pit Bull stuff.
     
  14. thepro8

    thepro8 Well-Known Member

    I'm not trying to dispove this product, trust me, I love pit bull products and would love for this thing to be a perfect solution, just have some questions.

    The same issue could arise for sts restraints because it too would have the same type of forces acting on it.
     
  15. Chip

    Chip Registered

    What kind of stresses do you think are being applied to a swingarm when the chain is pulling only on one side? What about when the bike is leaned over?
     
  16. Chip

    Chip Registered

    Simply, the swingarm and swingarm pivot area are extremely rigid.....unless you hit the thing with a bus, then you will not hurt it.
     
  17. KrashBandit

    KrashBandit The other guy at Pit Bull

    I think this may apply...but I may be wrong.

    Moment = Magnitude of Force x Perpendicular distance to the pivot
    force = mass x rate of change of velocity
    rate of change of momentum = mass x rate of change of velocity
    force = rate of change of momentum

    So while a moment is not the same as momentum, a lack of momentum would mean a lower moment of force, right? And Chip's right too...if he can't break it, nobody can:up:
     
  18. thepro8

    thepro8 Well-Known Member

    Unfortunately that's not right. Lack of momentum doesn't mean lack of force, it means there is a contradicting force acting in the opposite direction. For example, push down on the cement, no matter how hard you push, there is no movement or momentum, but there is a face from the earth pushing back on your hand.

    My professor would be so proud I still remember this crap
     
  19. Chip

    Chip Registered

    Math.....blah....blah....math.....blah......

    This didn't break the swingarm or swingarm pivot area.......then riding down the road in a trailer sure as hell ain't gonna break it! :D


    [​IMG]
     
  20. thepro8

    thepro8 Well-Known Member

    To really tell if this is in an issue the swingarm, join, and bold could be drawn in a cad system and put through a FEA (Finite Element Analysis). That would take into account he material properties and determine how much orational force it can truly take. It's also not hard to do if you have the setup. Could get it done within a day.

    The other option is set a bike up in the restraint system and do two test. First with a max side force scenario. Then inspect (maybe by taking measurements) on the swing arm, swing arm bolt and the joints where you connect the swingarm to the bike. You are checking for deformities.

    The second test is what I would consider the more important. Take the average side force the bike would experience when going through a turn on the trailer in the restraint system. Then repeat it may a couple thousand times for a couple seconds each and check do the inspection mentioned above.

    If it can handle those two test I think you would have a lot of consumer buy in.
     

Share This Page