How to Determine Correct 3,500 lb or 4,000 lb Leaf Spring For Trailer

Updated 12/22/2025 | Published 10/04/2024

Question:

I need new 4-leaf springs do my Keystone Bullet Crossfire 2430BH. Possibly upgrade from 3500 to 4000. What is correct length?

asked by: Loren H

Expert Reply:

Hello Loren,

I can help you determine the right replacement 3,500 lb or 4,000 lb double-eye leaf springs for your Keystone Bullet, though we don't have any way of knowing off-hand what specific ones you need. It's easy to find out though, as you just need to measure your current leaf springs from center-to-center of the spring eyes.

Keep in mind leaf springs also flatten out a bit over time, so go with ones that measure a touch shorter than what you currently have. For example, if your leaf springs measured 27-1/4" you could go with the 27" long 4-Leaf Double-Eye Spring for 3,500-lb Trailer Axles # e97SR.

I have added a link below to our entire selection of 3,500 lb and 4,000 lb leaf springs, which you can filter through by length, or if you let me know the measurement you get I can give you the right option.

expert reply by: Kyle S

Robin H.

12/22/2025

Hey Loren, what measurement did you get for the leaf springs on your Keystone Bullet? Once you have that length, I can help confirm whether the 27-inch 4-leaf spring or another option is the right fit. Let me know what you find—I'm here if you need a hand narrowing it down.