So, you’re ready to build your own homemade utility trailer?

If you’re not sure exactly what size and style you want, we’re here to help.

Homemade utility trailers come in all sizes and shapes, from tiny 4×8-ft teardrop trailers to stout 6×12-ft ATV haulers.

How to Choose a DIY Trailer Design

Before we begin, a reminder: We’re talking DIY trailers and general-purpose trailers here!

If you’re wondering, “Do I want a removable gooseneck or a double-drop car hauler?” then dare I suggest you’re browsing the wrong website! Heavy-duty haulers should only be designed by professional engineers and constructed by master, certified welders.

I recommend that home builders only build utility trailers limited to 7,500 lbs GVWR (Class III Hitch or smaller). 3,500 lbs GVWR is even better.

1. How Often Will You Use Your Trailer?

You may be thinking to yourself, “I’ll only use my trailer a handful of times a year.”

But owning a trailer is like Parkinson’s Law: Trailer use will expand to fill the weekends allotted. You’ll start cutting down your own Christmas tree, picking up free roadside mattresses, hauling your recycling en masse, etc.

So browse this list and identify ALL the possible uses you might have for your trailer.

What Will You Use Your Trailer For?

• Recycling, junk and garbage disposal
• Lawn and leaf clippings removal
• Moving lawn equipment
• Kayak, ski and snowboard transportation
• Motorcycle, snowmobile or ATV transportation
• Jet ski or speed boat transportation
• Camping and adventure
• Contracting and construction
• Picking up firewood
• Home improvement and house renovation
• Moving animals

Rule of thumb: When in doubt, overbuild a trailer. Better to overbuild it now than wish you’d overbuilt it later.

2. Where Will I Store My Trailer?

Will the Trailer Fit in Its Designated Parking Area?

Don’t trust nominal measurements. Use a tape measure. Measure the length, width and height of your driveway, garage, carport or storage unit.

Can You Safely Drive the Trailer to Its Parking Area?

Do a trial drive-through with your tow vehicle. Are there any low-hanging branches, bridges or power lines? One-way streets? Restricted narrow roads?

Will My Trailer Be Safe in Storage?

Yes, trailers get stolen. Don’t become a statistic. If possible, your chosen storage area should be off the road, private, under lock and key, preferably protected by a security camera system. Defend your trailer from vandalism and theft.

Will My Trailer Be Protected from the Weather?

Sunlight and moisture will degrade paint, cause rust, dry rot tires, and otherwise shorten the lifespan of your trailer. An ounce of prevention is worth a pound of cure! Keep your trailer in the shade, away from the rain. This will prevent cracked leaf springs, sticky brakes, frozen couplers, rotted decking, and rusted fasteners.

Caution! If you live in suburbia, check your HOA or CC&R regulations about trailer storage and on-street parking. For instance, some neighborhoods have restrictions against RV or equipment on-street parking.

3. What Is My Tow Vehicle Capacity?

To find out how much your vehicle can tow, read your Owner’s Manual or check the VIN sticker on the inside of your door jamb. If you can’t find a specific tow rating, look up the VIN details online or with the help of a local dealership.

As a quick n’ dirty estimate, just use the ol’ standby 80% rule: Assuming you’re not driving in the mountains or across the country, you should limit your maximum towing weight to 80% of the tow vehicle’s stated capacity.

• For additional resources, please read this in-depth article on how much you can actually tow.
• And if you don’t want to do the math yourself, here’s a handy towing calculator.

Next, check your hitch! You need to confirm that your hitch is capable of towing AT LEAST as much as your stock tow vehicle.

Hitches are rated in Classes:

	Receiver Size	Max GTW	Max TW
		Gross Trailer Weight	Tongue Weight
Class 1 (I)	1-1/4″	2,000 lbs	200 lbs
Class 2 (II)	1-1/4″	3,500 lbs	350 lbs
Class 3 (III)	2″	8,000 lbs	800 lbs
Class 4 (IV)	2″	10,000 lbs	1,000 lbs
Class 5 (V)	2″ – 2-1/2″	16,000-17,000 lbs	2,400-2,550 lbs

Heavy-duty commercial vehicles may have additional classes and sub-classes.

For more information, please see this helpful article on hitch classes from Curt Manufacturing.

If you plan to install a new hitch on your tow vehicle, it must be rated to at least match the capacity of your tow vehicle!

Equipping your vehicle with a bigger hitch than necessary does not mean you can tow heavier loads, of course. The weakest link still breaks the chain!

Common Towing Thresholds

The following numbers are estimates for factory towing weights. They are estimates only! You should also check your personal tow vehicle. These numbers are market estimates only. Also, they are only estimates for bumper-pull trailers, not fifth-wheel or gooseneck connections.

• 2,000 lbs: Medium-size cars, small crossovers and station wagons
• 3,500 lbs: Large crossovers and SUVs
• 5,000 lbs: Heavy-duty SUVs, half-ton tucks

After 5,000 lbs, most tow vehicle manufacturers will recommend or require that you have A) a factory-installed or factory-approved towing package and B) a weight-distribution hitch rather than a simple ball hitch.

• 8,000 lbs: Half-ton trucks with factory tow packages and recommended options
• 10,000+ lbs: Three-quarter and full-ton trucks*

4. What Is Required Cargo Capacity and GVWR?

You should carefully consider the empty (tare) and fully loaded (GVW) weights of your designed trailer. You need to calculate what cargo capacity you require.

For instance, a welded single-axle 6×10 steel utility trailer can easily weigh almost 1,000 lbs with decking and sides! Even the smallest steel trailers will weigh 300-600 lbs.

Aluminum frames weigh quite a bit less, but should not be used for heavier loads.

You will need to subtract the empty (tare) weight of your trailer from its Gross Vehicle Weight Rating (GVWR) to calculate the maximum cargo capacity.

For instance, if you build a single-axle ATV trailer with a GVWR of 3,500 lbs, and the trailer itself weighs 925 lbs, then your cargo capacity is 3500 – 925 = 2575 lbs.

Since most ATVs weigh less than 700-900 lbs, this trailer is strong enough for your application.

However, if you planned to transport a half-cord of firewood that weighs 2,750 lbs, then you would be 2750 + 925 = 3,625 lbs, which exceeds your GVWR and is neither safe nor legal.

Once you have estimated what cargo capacity you require, you can select your type and capacity of axle.

Introduction to Single-Axle Trailers

Single axles are commonly found beneath adventure trailers, equipment trailers, small cargo trailers, and general-purpose utility trailers.

They normally have a capacity (GVWR) of 1,200 – 5,000 pounds, with 2,000-3,500 pounds being the most common range.

If the GVWR is 3,000 pounds or less, some can be sold without brakes depending on state regulations. That is not recommended, however.

Single-axle trailers are easy to maneuver! They’ll practically turn on a dime. Unfortunately, they’re also a bear to back up. The shorter the trailer, the more difficult to reverse. They are also more prone to trailer sway at higher speeds. And, of course, a single tire blowout can be catastrophic.

Single-axle trailers are the most affordable, most common, and easiest to build.

Introduction to Dual-Axle Trailers

Dual axles are usually found beneath cargo trailers, car haulers, small dump trailers and camper trailers.

They normally have a total capacity of 4,000-10,000 lbs, with 5,000-7,000 pounds being the most common range.

Essentially all are sold with brakes and other upgraded equipment. Generally, dual-axle trailers are more heavy-duty than their single-axle cousins. They track better at highway speeds, but they are a bit cumbersome at slow speeds.

Suspension design and selection become much more complicated with dual-axle trailers.

Triple-axle suspensions are reserved for heavy-duty cargo haulers, Tiny Houses, and mammoth RV travel trailers. They are not addressed on this website.

	Single-Axle Trailer	Dual-Axle Trailer
Maneuverability	High	Medium
High-Speed Stability	Fair	Good
Tire Blowout Safety	Low	Medium
Ease of Backing Up	Difficult	Moderate
Cost	Low	Medium
GVWR Range (Common)	2,000-5,000 (lbs) – 3,500 TYP	5,000-10,000 (lbs) – 7,000 TYP

5. What Size of Trailer Deck?

Minimums

Unless you’re building a super-skinny kayak transportation trailer, the minimum width of most trailers is about 4 feet (48 inches).

Maximums

Any trailer wider than 80 inches – that includes fenders, lights, etc. – requires additional lighting to comply with Federal Motor Vehicle Safety Standards (FMVSS).

The legal maximum width in most states with an oversize permit is 8 feet (96 inches). This does not apply to all roads in the state! Major roads, like Interstates, many allow trailers up to 102 inches wide. However, smaller country roads may restrict widths to even less than 8 feet!

If you’re building a deck-between trailer, like most utility trailers, then that limits your maximum deck width to about 6 feet (72 inches). This is the most common deck width size for most utility trailers.

If you count every inch, you can get away with an 82″ wide deck and limit your total width to 96-102″. This is the typical width for a car hauler.

It is difficult to construct a deck-over trailer without utilizing I-beam construction, which is beyond the purview and skill of most home builders. Therefore, it is very difficult for a home builder to construct a trailer with a width greater than 72-82″.

6. Should I Include Sides on My Frame?

Unless you have an overriding reason for wanting an open flat deck, you should add sides to your trailer.

• Sides strengthen the frame.
• You can add a hinged ramp/gate.
• Sides allow you to schlep around bricks, sandbags, lawn clippings, and other loose items without spending 30 minutes strapping or tarping everything down.

Usually, a trailer with sides can do almost everything an open-deck trailer can – but not vice versa!

The exception to this rule is when you plan to build a separate structure on top of the trailer frame, such as for a teardrop trailer or cargo camper.

But in general, sides are well worth the slight weight and price penalty. Sides can be solid, mesh, or planks.

Without sides, many trailer frames require significant reinforcement.

Conclusion – How to Design a Homemade Trailer

To recap, here are the six big questions you should answer to choose your design for a homemade trailer:

1. What will you use your trailer for?
2. Where will you store it?
3. How much weight should the trailer be able to carry?
4. How much weight can my vehicle tow?
5. What size of a deck do you require?
6. Will I include sides?

From there, you can determine the width, length, sides, and axle type and capacity for your trailer.

Now, let’s get to work!