Is It Possible to Add an Axle to a Single Axle Trailer

Updated 07/02/2025 | Published 02/01/2021

Question:

I have a ? Is it possible to add another axle to a Single trailer it’s a 5x10

asked by: Francisco

Expert Reply:

It is possible, but you'll need to use the linked formula to determine the correct axle placement. Because you're adding an axle, you'll likely need to remove the existing spring hangers and reposition things so that the center spring hanger sits right about where the original single axle used to sit, but the formula will walk you through that.

Also, keep in mind that if you add an additional axle with the same capacity as the existing, you won't necessarily double the weight capacity of the trailer. You still might be limited by the capacity of the coupler or the structure of the trailer itself.

You'll also need new spring hangers and you'll need to add an equalizer and springs but the specific parts needed will depend on the capacity of the axles used.

expert reply by: Mike L

Bryan

6/26/2025

Mike i have a 1987 continental trailer. the gvrw is 4000#s, but boat and trailer both weigh 4250#s but when we load the boat with vacation supplies it is heavier. i have twice in 3 years blown tires on our return trip. would putting a second axle on the trailer help with the added weight or would adding different leaf springs make a difference. Thanks, bryan

Mike L.

7/2/2025

@Bryan A second axle would help, for sure. That being said, it still won't increase the capacity of your boat trailer. You'll be limited by the capacity of the lowest-rated component. The secondary axle and springs will increase the capacity of those components only, if the coupler, the bunks or the frame of the trailer itself is rated lower, you'll be limited to that amount.