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How to Build a Car Trailer

Kalpana Kumari
A car trailer is a useful personal belonging, and building one involves just a few simple steps. However, welding skills, and availability of all the parts and tools, are the two basic requirements for building a car trailer.
A car trailer comes to use when you have to move from one place to another, or when you want to transport your elegant car without putting any mileage on it. It is highly useful to car racers as sports cars are not authorized to run on the streets. So, car trailers are frequently used to get the cars to the track.
Purchasing a car trailer from a dealer would be costly. If you feel the need to have one of your own, you can cut down the expense by building a car trailer yourself. The required materials are easily available at junkyards and auto parts shops. Following are the basic features of a car trailer accompanied by a brief overview of how to build a car trailer.


If you wish to build a car trailer, remember that an ideal one should be long enough to accommodate cars and small trucks. The minimum recommended length and width for a car trailer is 16 feet and 9 feet respectively.
A car trailer is rectangular in shape. Weld a rectangular frame out of 4 by 4 inch steel. The length and width of the trailer should be 16 feet and 6 feet 6 inches respectively. Maintain accuracy in measurements while welding. Cut five cross bars of 6 feet 6 inches in length. These should be attached to the inside of the frame.
Weld one at a distance of 1½ feet from the center, and just at the center of two axles. Join two cross bars beneath the spring hanger mounting points, one at the back of the frame, and weld the last cross bar along the length, joining the middle points of the two short sides of the frame.
The frame is covered by heavy gauge metal plates. Approximately, 104 square feet metal is required to cover the whole frame.
However, covering the entire car trailer is not necessary. Just attaching runners for the tires would be enough. To do so, you need two long strips equal to the length of the car trailer. Textured metal runners would be highly beneficial as they provide traction to the vehicles driving on them.

Fold-Down Ramp

It should have a fold-down ramp as this would ease the loading and unloading of the vehicles. An adequate length is three to four feet.


A car trailer can be constructed with either one or two axles. It is always advisable to install two axles as they provide greater support and are better shock absorbers. Going for mobile axles would be even more beneficial as they are able to support much heavier weights and give a smooth ride.
Try to find axles with springs and brakes. If the parts available with you do not fit appropriately, you can always weld them accordingly. Axles are fitted beneath the car trailer. The car trailer is quite heavy and you might need machines to lift it up.


Wheels must be attached to the axles as they ease heavy load hauling. There are tires specially made for car trailers. Bias ply nylon tires are considered to be the best. They are available in 14½ inch and 15 inch sizes. It is always advisable to keep a spare tire as you might need it in any kind of emergency.


In order to make a hook for the car trailer, cut 4 by 4 inch steel into an 82-inch piece. Cut the piece into two identical halves lengthwise.
Weld each along the bottom of the frontal parts of the long sides of the frame, such that the first half of the piece length joins together to form the upper two sides of a triangle, and the second half touches the long sides of the frame. Weld the tips of the front halves together. This front portion acts as the hook.

Cover Base and Wheel Runner

Both the cover base and the wheel runner are essential. A cover base facilitates the hauling of cargo and vehicles. A wheel runner is required to ease the job of checking and repairing under the vehicle while it is on the car trailer.


A backlight kit and brake controller are easily available in any auto parts shop. Fix the backlight kit in the area of the car trailer or as prescribed by your state. Connect the backlight kit to the front of the car trailer through wires.
This is a simplified description of how to build a car trailer. Once it's constructed, street legality of the vehicle must be ensured. It is always recommended to test it well before attempting to load a vehicle on it.