horse trailer

Three main factors to consider when deciding what size horse trailer will fit your needs – and the needs of your equine companions!

Horses first. Horse trailer second. Tow vehicle third. It’s a simple formula, and it makes sense when you think about it. But it’s surprising how many horse people buy a tow vehicle before knowing for sure what it needs to pull. Many of us want a tow vehicle that can be a great everyday vehicle during the week, and that can tow a trailer on the weekend. But when the tow vehicle is chosen first, the buyer often finds it doesn’t quite meet the requirements for safely pulling a fully loaded horse trailer. When that happens, owners start looking for a lighter and smaller trailer to keep the weight down; but if the trailer is too small or insubstantial for the horse(s), problems can arise. In other words, the buyer is trying to fit the trailer to the tow vehicle instead of to the horse(s).

Horses first

To choose the right trailer, start by determining the size of the horses you have now, and the size of those you might have in the future. If you have Warmbloods, for example, your trailer will need to comfortably fit horses from around 16 to 18+ hands, which requires a stall length of 11’ and an interior height of 7’8”. If you have Quarter horses, you want to make sure your trailer will fit animals in the range of 14 to 16.3 hands, necessitating a stall length of 10’, and an interior height of 7’4” to 7’6”.

To choose the right trailer, start by determining the size of the horses you have now, and the size of those you might have in the future.

Horse trailer second

Once you know the size and weight of your horses, you have the information you need to choose the right-sized trailer. Keep in mind that a horse needs room, light and ventilation to stay sound and healthy during transportation. It is important that he has enough head room. He needs to be able to stretch out his neck for balance, to cough out any hay or dust that might lodge in his respiratory system, and to stand in a natural position. If the horse can’t lower his head to cough out hay dust or noxious gasses, he can be at risk for shipping fever. Interior height is also important. A horse is less stressed and less claustrophobic if he can lift his head without feeling the roof is restricting him.

Stall length is measured from butt to breast bar. A horse should fit between the two without being squeezed, yet not have so much room that he could be harmed by going up over a breast bar or being thrown into it during a sudden stop. The width of your trailer stalls is also very important. A horse can keep his balance quite well if he has room to spread his legs. That’s why we recommend a partial center divider, which doesn’t extend to the floor. A lower center partition will restrict the horse’s ability to spread his legs and keep his balance. Of course, there are exceptions. Some horses, who have had poor experiences in the past, have learned to lean on the dividers; but usually, once given the right amount of room, they learn to keep their balance without leaning. Some horses will learn to climb the trailer walls if they don’t have enough width to follow the motion of the trailer.

Once you determine the size of trailer that will keep you and your horses safe and comfortable, you need to determine its loaded weight, or use its Gross Vehicle Weight Rating (GVWR), which is stated on the trailer as the maximum weight it can carry and still be safe. When you figure in the weight of your horses, plus tack, feed, hay and water, make sure that total is not more than the GVWR. You should never exceed the trailer’s capacity as determined by the manufacturer. In general, most well-constructed, two-horse bumper pull trailers with a dressing room will weigh around 3,200 pounds. Add two 1,200-pound horses and some tack, and the trailer will then weigh about 6,000 pounds. The GVWR of most two-horse dressing room trailers is 7,000 pounds. In this case, you would use the GVWR to determine the capacity of the tow vehicle you’ll need.

You should never exceed the trailer’s capacity as determined by the manufacturer.

Tow vehicle third

Now you have all the information you need to choose a safe tow vehicle. There are three criteria to use when choosing the right vehicle:

  1. The tow rating – this refers to how much the vehicle is rated to tow safely. For example, a trailer with a GVWR of 7,000 pounds (but with a loaded weight of around 6,000 pounds) should have a vehicle that can tow at least 20% more than the loaded weight. But since most horse owners don’t weigh their trailer when fully loaded, to play safe it would be best to choose a tow vehicle that has a tow rating equal to the GVWR of the horse trailer, but preferably have a tow rating 15% higher. So a trailer with a GVWR of 10,200 pounds should use a tow vehicle with a tow rating of at least 10,200, but preferably 12,000 pounds. But the tow rating is not the only factor.
  2. The wheel base length – this is the distance between the front and back axles of the tow vehicle. The longer the wheel base, the more stable the vehicle. With bumper pull trailers, vehicles with a short wheelbase tend to bounce from front to back due to the trailer’s tongue weight pushing down on the rear hitch. This causes the front end of the tow vehicle to lift (float), giving you less control. Floating can be corrected by a weight distribution system (often mistakenly called sway bars), which is highly recommended.
  3. The curb weight – Some very light tow vehicles have a fairly good tow rating, but you don’t want the “tail wagging the dog” so to speak. A tow vehicle can weigh less than the loaded weight of a bumper pull trailer, but it shouldn’t be by much less. The Combined Gross Vehicle Weight Rating for the tow vehicle will tell you how much the whole rig should weigh and still be safe. For larger gooseneck trailers, such as a four- or six-horse trailer, the difference between the trailer’s weight and the tow vehicle can be greater. For example, a truck pulling a loaded six-horse trailer weighing 16,000 pounds can be pulled with a one-ton truck rated to pull 20,000 pounds, but the truck itself will weigh 6,900 pounds.

In summary, the formula is simple:

  • Horses first – determine their size and weight.
  • Trailer second – determine the size, style and strength (construction) that will best keep your horses safe.
  • Tow vehicle third – choose the vehicle that meets all the requirements to safely pull your chosen trailer and horses.

Understanding trailer stall length

It’s important to realize that a stall may not only be too short – it can also be too long.

  • In a straight load trailer, a horse with too much stall length from butt bar to breast bar can be tossed too far forward into the breast bar if you stop suddenly. Too much length can also give the horse room to go up and over a chest bar.
  • A slant load trailer does not have butt or breast bars, but stall lengths are limited by the width of the trailer, which is set by the Department Of Transportation. Most stalls in slant load trailers are 36” to 44” wide, which makes the usable length of the stall only about 8’6”. This means horses over 15 hands just won’t fit comfortably. Be careful when getting slant load stall measurements – some dealers will give you the diagonal length (far corner to far corner) which will measure about 2’6” longer than the actual usable horse space.

For more in-depth information on trailer terms and safety, visit