Replacement Leaf Springs for 5th Wheel With Curt 7k Axles

Updated 06/30/2026 | Published 06/23/2026

Question:

Hello. I have a 5th wheel trailer with 2 Curt 7000lb axles. I’m looking to replace the current leaf springs with 4000 lb leaf springs. What do I need to ensure I’m ordering the correct size? As well, I’m certain they will need bigger u bolts than what is attached to the current 3000lb leaf spring configuration. Can you assist me with exactly what I will need to install this upgrade? Thank you, Jeff

asked by: Jeff K

Expert Reply:

Hey Jeff! To find the right replacement you need to measure the length of your leaf springs. See the attached photo. All of our leaf springs for 8k axles (4k each spring) like # e89FV measure 24-7/8". If that matches what you have you can use these as a replacement.

Longer U-bolts may or may not be required, it depends on the current length, and your current leaf springs. If you have 7-leaf right now it won't be an issue. If you have like a 3-leaf spring that would get you into the territory of needing longer U-bolts. If they're worn just replace them either way.

What kind of 5th wheel do you have? If your measurements don't match, I can help you find the right 7k replacement if you add the length in the comments below.

expert reply by: Robin H

7-Leaf Double-Eye Spring
(click to enlarge)

Leaf Spring Measurement
(click to enlarge)

Bill F.

6/28/2026

I used these springs on dual Dexter 7000 pound asked. The old springs were 3500 pound 6 leaf Dexter springs. I did have to get longer U bolts because of the added leaf. I have fun these for over a year now with 2 trips to Florida and they are doing fine so far.

Jimmy

6/28/2026

I replaced 3500lbs springs on my jayco pinnacle. These 4000lbs springs were fractions on an inch shorter, no issue there. the u bolts did have to be replaced even though I thought my current u bolts had the length.

William

6/29/2026

I had to replace a 7 leaf/ 4,000 lb. leaf spring on my Grand Design Solitude after it broke due to over loading the back of my trailer storage units. This leaf springs matched up with the three existing ones still in place. My axles were upgraded to 8,000 pound and from Dexter under the original purchase order. I reused the U-bolts and plate and made it work. If I were doing it again, I would have gotten all new hardware as it doesn't cost much more. I fought the old U-bolts and had to retorque them several times after driving for awhile.

Bill C.

6/30/2026

I recently replaced my 7000lb 6 leaf Dexter axel leaf springs with 7 Leaf 8000lb etrailer springs and I couldn’t be happier. The surging I had experienced with the 7K springs has all but disappeared, not to say there was none but not enough to mention. 1 of the spring leafs had broken and required replacing so upgrading to 8K was the way I went. I’m not an auto mechanic but I grew with a father who was and I learned plenty from him. A couple things I didn’t know was the end of the spring that has the safety band is the forward end. Secondly, you do an axel (in its entirety) at a time. I tried a wheel at a time which made it nearly impossible to align the centering bolt with the frame and the spring plate. By removing the U-bolts and supporting the axle with jack stands you can move the axle and springs however you need to align everything. Not knowing those two things tripled my level of effort. As it is, t just pulled my 38 foot 5th wheel about 200 miles and all indications are full steam ahead. 100% satisfied, all smile.