Determining Spring Hanger Spacing for Tandem Axle Trailer Fabrication Project

Updated 08/30/2016 | Published 08/29/2016

Question:

Hi ... I have a pair of 26 inch 5 leaf spring and have a temporary mock up tack weld with the center axle space at 33 inches. John H says the center axle distance are to be placed between 33 to 35 inch range. The outside hangers per preliminary recommendation are 29.5 inches on center hole side hanger from the center hole equalizer hanger. When I check the movement of the equalizer to see if it hits the bottom of the rail supporting the trailer load that is clear by 1/8th of an inch and has this clearance as the equalizer arm stops at the hanger first. When both springs are level the hanger straps from the equalizer go left and right from center at 45 degrees equally and look like the pictured diagram offered. Question is it better to move the outside hangers to 30 inches apart and not the 29.5 inches John H recommended as a starting place to mock up the springs to see how they operate. I do not like the equalizer hanger stopping on the metal to metal contact with the equalizer arm. Doing so will open up the equalizer strap angle to perhaps 50 degrees as well as open the distance of the center leaf springs to 34 inches from their current 33 inches. I am hoping doing so will stop the metal to metal contact of the equalizer to its support bracket.

asked by: Alan M

Expert Reply:

Thank you for the measurements you provided and for the photo of your trailer suspension mockup showing the spring components' spacing.

As long as your shackles do not hit the trailer frame (you mention 1/8-inch clearance) you should be fine, but if you'd like a bit more breathing room you could increase spacing from 29-1/2 to 30-inches without negatively affecting anything else.

expert reply by: Adam R