Determining What Hanger Spacing For Tandem Axle Trailer Using 28-3/4" Long Leaf Springs

Published 09/22/2021

Question:

Hi I have 730mm eye to eye spring We need to built boat trailer. We have tri axle components such as 1 1/2" front and rear hanger Equlizer 7 3/4" Shackles 2" But I need you help for mounting distance for hangers

asked by: Antony

Helpful Expert Reply:

I would be happy to help, but the only way to find the exact location for mounting the hangers to your boat trailer is going to be by tacking the hangers in place and moving them around until you get the suspension correct. When done correctly the shackle straps on the equalizer should point like a W like in the included picture.

Your 730mm spring translates to 28-3/4" which is not a very common length so there is not exact hanger spacing anywhere for a spring that length.

On all of the hanger kits we offer with a 7-3/4" equalizer the hanger spacing is right around 4-3/8" longer than the leaf spring being used, so following that same formula I would start with hanger spacing around 33-1/8" and go from there until you get the correct suspension geometry.

In addition to the hanger spacing you will need to make sure that you are placing the axles in the correct location to keep you tongue weight in the 10-15% range. Since the weight of boat trailers are typically far back due to that being where the motor is the axles are typically pretty far back as well. I included a link to a helpful article on determining where to place axles on a trailer for you to take a look at.

expert reply by: Samuel C