Leaf Springs for Trailer Carrying 20-ft Pontoon Boat

Updated 01/08/2018 | Published 01/06/2018

Question:

My 18 ft pontoon when pulling bounces up and down quite a bit and you have to slow down to get it to stop bouncing it has 25.25 4 leaf spring.would you go with a six leaf spring ? And would I need a u bolt kit to install and how do I measure the size of axle 2 or 3 inch.

asked by: Al

Helpful Expert Reply:

If your trailer has the correct carrying capacity for your pontoon boat and if the trailer's suspension is in good order you may not gain anything by switching to 6-leaf springs. Trailer leaf springs are made with varying numbers of leaves and they are selected based on their specific weight rating which needs to match the axle. Spring length also matter too, of course.

If the springs are rusted/badly worn you may just need new ones of the same rating. The double-eye leaf springs we have in your length of 25-1/4-inches are rated for different capacity axles, for example part # e68SR which is a 4-leaf spring rated for a 3500-lb axle.

All of our double eye springs are displayed on the linked page. Be sure to measure your leaf spring length when it is not under tension and choose the weight rating based on the axle weight capacity.

The linked article on trailer suspensions will be helpful; it includes the typical diameters for axles of various weight ratings. Your trailer's main sticker should have axle ratings or they will be found on the stickers or plates on the axles themselves.

Sometimes trailer bounce just happens from driving speed and there will sometimes be no better solution than slowing down. Note that trailer tires do carry speed ratings and for safety reasons you do not want to exceed that rating for your particular tires. Tires use a letter code for speed ratings, such as L for up to 75-mph and M for up to 81-mph, and these will be noted on the tire sidewall along with the required psi pressure for safe operation.

expert reply by: Adam R