What Factors to Consider when Picking Out a Leaf Spring when Adding an Axle to a Trailer

Question:

hello, i have a trailer that i am adding springs to the orignial spring pack, i was wondering what math formula i would need to use to figure out the new spring rate depending on how long or short of a leaf spring i would add from the new pack to the old pack. i have used the formula for determining the spring rate of the total pack but am getting bogus numbers like 22k pounds per inch. basically i need to know that if i have a 42 inch long main leaf in a 4 leaf spring pack and i add say a 27 inch spring of the same length and thickness what will be my new spring rate? i hope this makes any sense at all. thanks

asked by: Bob M

Expert Reply:

A much easier way to determine what replacement leaf springs you should be using on your trailer would be to first determine what the total weight of your trailer will be and then pick springs that are confirmed to be able to handle that weight.

For example the # e34SR that you referenced is designed for 6,000 lb axles. If your tandem trailer will weigh 12,000 lbs this would be a great choice for a spring. Trying to use the dimensions that you mentioned would be a tedious method that wouldn't exactly tell you what you need to know. I can't tell you how many lbs of capacity a spring would have if you added a new leaf to it.

expert reply by: Jameson C