Tandem to spread axle conversion on a flatbed trailer?

Guys & Girls it would be better to just by a spread axle trailer. Truth be told a tandem axle tires don't wear down like spread axle tires. I understand the desire not to want to slide tandem but we are in the keeping in shape business right.
It is pretty easy to figure out the positioning of the tandems after doing a few loads for me anyways. All the best on your project. Keeping it simple

 

Putting a lift axel on might be less expensive,

 

Been done millions of times. Depends, is a fixed tandem, sliding tandem. Air or spring. But a quality truck shop can do this.

 

Is this a 53 foot trailer?
Why do you want to do this?

 

Well I would try to buy new hangers and use your axles, but this may be limited to your brand/type. Measure off king pin and a plum bob to locate new axle. You may or not have to fab crossmenbers for upper air bag mount. Extend air lines. Make sure to have a 10'2" axle spacing. Its not easy and can be expensive. But it can be done. I would plumb a dump into rear axle.

 

A plus with a tandem over a spread is they are easier to maneuver, the minus is loading, with a lift at the end of the trailer it would eleminate that,

 

I think your going to find that the cost of doing the modification correctly and with quality, will cost more than may be worth. Once you modify something like a trailer, your going to have to live with it for a long time. While you may have added usefulness to it, you have more than halved the resale on it.