Leaf Spring Recommendation for a Trailer to Stiffen Up Suspension that has 3,500 lb Axles

Published 06/19/2015

Question:

I have a boat trailer with a single 3500 LBS axle. It has the factory 3 leaf springs. With the boat on the trailer, the trailer seems to nearly bottom out on some highways. The load in the boat should not be considered overloaded. Would going to 3500 lbs 4 leaf springs take some of this bounce motion away?

asked by: Richard

Expert Reply:

Regardless of the amount of leaves a leaf spring has if the capacity is the same between two of them they would both flex and bottom out the same.

I would recommend you have your trailer and boat weighed so that you know whether or not you are overloading the trailer/leaf springs. You should note that going to a heavier spring won't necessarily give your trailer a higher weight rating, just a higher spring rating.

For a higher rated spring you would want the part # e28SR as it has a 4,800 lb axle capacity and has the same dimensions as most 3,500 lb leaf springs. This would give your trailer stiffer suspension, but not additional capacity.

expert reply by: Jameson C