Tips for Buying a Used Boat Trailer

buying used boat trailer

If you are buying a smaller boat, then you are likely looking at buying a trailer as well. Used boat trailers can be a good deal if they are in good shape. Many used boats are also for sale with the trailer included. But how do you know if that used trailer is actually a good deal?

Before you buy a used trailer you want to give it a good examination to be sure that it is roadworthy for your boat.

If you’re looking to buy a used boat trailer now or planning on buying a boat that comes with a used trailer, Boat Owners Association of The United States (BoatUS) has shared some recommendations with us for buying used trailers to keep in mind.

Measure Boat Trailers Well

Trailers should come with a capacity plate indicating how big of a boat you can trailer, but don’t count on that still being legible on used trailers. With older trailers, the capacity plate or sticker may be long gone or too hard to read after being outside in the weather for years.

To determine a rough idea of a spring-axle trailer’s capacity, simply measure the diameter of the axle. An outer diameter (OD) axle tube size of 1.75” is typically rated for about one ton; 2.375” for 3,500 lbs.; and 3” for 5,200-7,000 lbs. – remember to subtract the weight of the trailer from the gross capacity.

Check Your State’s Regulations

All trailers are not built with the same specifications and regulations because each state may have different trailering regulations. While most states require brakes for trailers rated to carry more than 3,000 lbs., some states require brakes on trailers as light as 1,500 lbs., while a few others let you coast up to 4,500 pounds (although that’s not recommended). It can be expensive to retrofit brakes, and some states such as Florida require brakes on each axle.

With this in mind, you need to be careful about buying a used trailer out of state. State-specific trailer registration information can be found at

Tire Diameter Matters

After an hour at highway speeds, a 13-inch tire will have spun 10,000 revolutions more than a 15-inch tire, which means more heat, bearing wear and increased chance of problems. Having a fully serviced spare tire ready to go – and the tools to install it – will also solve many of the most common reasons for a trailer breakdown. If all else fails, having an annual BoatUS membership with Unlimited Trailer Assist roadside assistance to safely tow both your boat trailer and tow vehicle up to a 100 miles will make a bad roadside breakdown suddenly get much better.

Ensure Proper Paperwork

Watch out for paperwork snafus with ownership documents for the used trailer. If the trailer is missing the vehicle identification number (VIN), it cannot be legibly read or doesn’t match ownership paperwork, you may run into an issue with the DMV and have to apply for a replacement. It’s better to have the seller handle this before the sale.

More Trailer Parts to Check

In addition to these tips, BoatUS offers an even deeper dive in their used boat trailer buying guide on what to look for when inspecting parts of a used trailer.

Additional trailer parts to examine include:

  • Axles and Suspension
  • Frame and Fenders
  • Tires and Bearings
  • Trailer Wiring
  • Lights and Reflectors
  • Brakes
  • Trailer Coupler
  • Safety Chains

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Diane Seltzer

View posts by Diane Seltzer
Diane is the founder of as well as the boating lifestyle site for kids Active in the boating industry, Diane has also led the marketing for multiple recreational boating businesses and startups.


  1. Harper CampbellJuly 26, 2017

    My husband and I just bought a boat, and now we need a trailer to tow it around. It’s good to know that when it comes to finding the right one that we need to measure it well, so that we will be able to know it fits our boat. Personally, I never even thought about doing this because I thought it will be one size fits all.

  2. ScottDecember 21, 2016

    I had never considered to check for the VIN number on trailers. I can see why it would be important to know about this before registering it with the DMV to avoid any problems or complications. My dad has been looking into buying a boat to take all of his grandchildren boating on. I’ll have to make sure I mention this to him the next time I see him.

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