1. Eugene
    January 28, 2019 @ 10:53 AM

    Hi. Nice article, helps me a lot on my project. I am thinking of the triple axel set up and was wondering what the spacing is on the axels? Thanks


    • The Mechanic
      January 28, 2019 @ 11:05 AM

      Thanks for the note. Axle spacing depends on several things like spring length, tire & wheel size, hardware and more. There are some standards, so I recommend following info from the axle and hardware manufacturers. For instance, this PDF gives suggestions for Dexter axles and hardware based on each axle capacity. Good luck with your project.


      • Eugene
        January 29, 2019 @ 10:45 PM



  2. Nickolas Lockard
    May 9, 2019 @ 1:27 PM

    Why no analysis or discussion on air bag suspended trailers? Intuitively, I’d think they suffer some of the frame loading stress concentration issues as torsion axles, for maximum deflection bumps (hitting the hard-mounts).

    On the other hand, if I’m right in my intuition there can be solutions for that. And, there should also be the advantages that airbags have:

    1. variable ride height
    2. variable spring rates
    3. some natural damping effects of the rubber
    4. suppression of a wide band of vibration frequencies, which protects both trailer and it’s load from fatigue loading stresses

    Downsides are: if you develop a leak or have un-repairable rubber tears, cracks, or rots, then road-side repairs are made more difficult, and you may not be able to safely limp home on a jerry-rigged repair.

    I mean virtually all OTR trucks have gone to them. And they’re no more expensive than other systems really. What’s your opinion and analysis?


    • The Mechanic
      May 9, 2019 @ 6:32 PM

      Good comments and good observations. Thanks for the questions. Unfortunately I don’t have much experience with them. The trailer axle kits available for DIY are more expensive with a lot more going on, so they don’t appear much. I like your intuition, and I don’t have much to add either way. Maybe a comment on required monitoring and maintenance.


  3. Thomas Pietsch
    September 2, 2019 @ 9:17 AM

    I making a 16′ double axle trailer with slipper springs and I would like to know the proper positions to put all three brackets for the springs. Center pivot and the 2 outside brackets. The springs are 26 1/2″ from center hole to end with 3500# axles and the A frame tongue is 54″ out from the front frame. Thank you in advance for your response, Tom.


    • The Mechanic
      September 2, 2019 @ 10:15 AM

      Good questions. Please check with your spring / axle manufacturer to see their requirements. Most have some dimensional documentation to give the dimensions you need. For the axle placement on the trailer, please see our article with the needed axle position equations.


  4. Kenneth Gregory
    August 5, 2020 @ 10:01 AM

    My vpn has interrupted this… I’ll try again
    You guys are so helpful. More business’ should operate with this sort of approach. Do well and prosper for it!



  5. Ryan Overton
    January 29, 2021 @ 10:20 AM

    This is very comprehensive information, so I’m asking the creator of this for help: I’m attaching a link to a picture of my oddly worn axle triangles. I’m assuming this problem is caused by incorrect axle positioning, but could it possibly be caused by rear axle brakes? I’ve never seen triangles wear like this before…



    • Mechanic
      January 29, 2021 @ 12:03 PM

      There is a lot here. First, I agree, that’s a different wear pattern. I don’t think it’s brakes. The wear is a straight-ish vertical line, so it’s likely suspension loading is symmetric. Probably not incorrect positioning either. Your guess about one causing the other is possible, but I personally guess it’s poor quality parts. There should be a bushing in the eye to keep it from wearing into the cast material, but I’m guessing that was not there, or bad, so it wore quickly. The bolt is much harder than the cast, so after wearing through the thick part, the thin area went relatively fast. These parts are under-rated or just cheap junk. I’d replace with all new parts (rocker, bushings, bolts), then keep an eye on it. I’m also wondering if an imbalanced wheel would exacerbate this, causing it to fret all along the drive? Good luck.


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