I recently purchased a tandum axle boat trailer that needed the leaf springs replaced. I measured what was left of the rear springs and the intact front, both messured to be 20 inch from eye to eye. I purchased new springs and put it all together, but the rear springs are tilting the axle about 5 degrees forward and the equilizer is not even to the front springs/axle it seems that either I need to put a shackel on the rear mount of the rear springs or get a longer spring for the rear, I always thought that on tandum axle trailers the leafs are the same size front and back, am I wrong? any help appreciated
asked by: Robert J
If you do not have the boat on the tandem axle trailer, what you have mentioned is how the trailer suspension will look without a load on it. The equalizer will be up in the rear and the rear spring will be tilting the axle forward. The reason is because the rear tires on your boat trailer are made to scrub when turning and with the suspension set up this way it keeps the majority of the load on the trailer from being put on the rear tires.
If the boat is on your trailer and the trailer suspension is sitting with the rear axle tilted forward and the equalizer not level, then you have the boat up on the trailer too far. The boat will have to be moved back so the trailer will be loaded correctly.
On a tandem axle trailer the leaf springs are the same size, front and back. You will want to make sure you have the correct size leaf springs for the trailer axles weight capacity.
A leaf spring like the 3-Leaf Double-Eye Spring, part # SP-169275, has 3 leaves and a eye to eye measurement of 20-3/8 inches and is rated for 1,000 lbs., so two leaf springs will work on a 2,000 lb. axle.
A correct leaf spring suspension on a tandem axle trailer will have four same length leaf springs attached to the center hanger of the trailer with an equalizer and shackle straps.
I am including a link to a FAQ page on a double-eye trailer suspension.