What Axle Capacity Leaf Spring for 2018 Jayco Seismic 4212

Updated 03/04/2025 | Published 03/02/2025

Question:

Hi, I have a 2018 Jayco seismic 4212, I would like to replace the leaf springs this summer, the trailer has Dexter 7000 lb axles, what would be the best leaf springs to replace with, 7k or the 8k springs. Thank you Tim

asked by: Timothy F

Expert Reply:

Hey Timothy, I know the temptation is to go with a higher rated spring since bigger is better. But in reality the correct rated spring will give you a better ride quality since the heavier the spring the stiffer it will be.

So instead I would recommend a 7k spring like the part # TRU52FR which will provide a much better ride quality.

You do need to make sure you get the right length spring too. The TRU52FR is 25-1/4 inch long and is a very common size so be sure to measure what you have.

expert reply by: Jameson C

Timothy F.

3/4/2025

Jameson, Thank you, for the reply, I already have 7 leaf, leaf springs on my trailer, they measured 25.5 inches, probably because of the weight on them. I would imagine that the 24 7/8 you mentioned would fit. So what would be the next option? Tim F

Jameson C.

3/4/2025

@TimothyF Glad to help! If you can measure with the weight of the trailer off of the suspension that would be your best option for getting correct length. For 24-7/8 inch spring we have the part # e64SR though. The weight of your trailer on the suspension could be stretching the spring a decent amount and the 24-7/8 inch spring would be accurate or it might just barely flattening it out and instead the # TRU52FR would be what you'd want.