Can a Second Axle be Added to a Single Axle Pontoon Boat Trailer

Updated 01/31/2017 | Published 01/30/2017

Question:

I am going to buy a pontoon boat trailer. It has single axle but I would like to ad a second axle because I think my pontoon is very heavy for only one axle. To do that, can I just buy a second axle and springs and install it, or I have to take the existing axle and buy a tandem system ? I will appreciate all the info that you can provide to my lack of knowledge. Thank you in advance,

asked by: Marcos P

Helpful Expert Reply:

I would only add an axle if it is really needed. Otherwise you are making more work for yourself than is needed. But if you do add an axle then I recommend making it a true tandem set up for better ride quality and so the 2 axles can work together and not independently.

Adding an axle is going to involve taking some measurements and doing a little math. I have included a picture that shows how to determine axle spacing on a trailer build. Once the positioning is figured out you can select the other components needed such as the springs and hardware.

A tandem axle set up will require a total of 4 double-eye springs, 2 front hangers, 2 center hangers, 2 rear hangers, 2 equalizers, 8 shackle straps, 14 shackle bolts, 4 u-bolt sets (total of 8 u-bolts), and 4 u-bolt plates. You will probably be able to reuse some of the parts you already have. I have included a link to a help article on trailer suspension and a link to trailer suspension parts for you.

Another option is to replace the axle you have and add 2 axle-less systems. I have included a link to those systems for you.

expert reply by: Michael H