What Is Normal Deflection Of Leaf Springs On Trailer

Updated 07/07/2016 | Published 07/06/2016

Question:

I completed a axle flip on my 24’, 1996 Terry fifth wheel several years ago and have since wondered about the increased distance between the top of the leaf spring stack and the frame. I have calculated a guess the original distance was about 3 inches. This three inch apace limited the travel of the axle and springs to three inches. There is a steel square tube welded to the frame above the axle I assume to act as a stop to limit the vertical travel. Now that the axle is on the bottom side of the spring the space is approximately 6 inches. This increased distance permits the axle and springs to travel beyond the original 3 inches. I have a duel axle system. Hangers are 4 ¼ tall, at 25 inch spacing. The equalizers are 5 ¾ inch with a 2 inch vertical distance to the top bolt hole. Shackles measure 2 ¼ inch. Springs are 4 leaf, 1 ¾ inch wide, about 21 ¼ inch in length. Axles are Dexter model 2800, 2800 Lb rating. Camper grouses out at around 6200 Lbs. I am thinking about having a new stop attached to the bottom of the frame above the axle that will again limit the spring travel. What is a safe vertical travel for the leaf spring? Thank You,

asked by: Jim F

Helpful Expert Reply:

The typical spring deflection for leaf springs on a trailer is up to 1-1/2 inches when at capacity.

The recommended clearance with leaf spring suspension on an unloaded trailer is between 2 - 2-1/2 inches. It sounds like you have a little more than that since you flipped your axle. Leaf springs only tend to deflect about 1-1/2 inches when carrying a load.

expert reply by: Jeffrey L