When you are on the road with your trailer, you not only have the responsibility to your horse to keep him safe, you also have the responsibility to yourself, whoever is riding with you, and to all the other drivers out there on the road. You certainly don't want to be responsible for causing an accident that may result in injury or death to someone else. By making the right choices, you can maximize your chances to be safe.
Before choosing your tow vehicle you should know how much your trailer weighs. The number on the sticker on the trailer is not the weight of the trailer, but the GVWR, (Gross Vehicle Weight Rating) or the manufacturers recommended capacity of the trailer including the weight of the trailer itself and any thing being hauled in it. The trailer should never be loaded past that recommended capacity.
The actual weight will sometimes be listed on the Certificate of Origin or the title, but not always. You can take it to a scale to get an accurate weight. Once you have the weight of the trailer, then add the weight of the horses, hay, grain, or any other equipment and tack you have on board. That will give you the GVW, (Gross Vehicle Weight) or the actual loaded weight of the trailer.
When you choose the tow vehicle, the easiest and best way is to just use the GVWR of the trailer because you know the trailer will not ever weigh more than that amount unless you overload it. This also gives you the safety margin you need to haul the live shifting weight of horses.
Once you know the weight of your trailer then you know how much the tow vehicle has to be rated to pull your trailer safely. Hauling with a vehicle that is inadequate will put extra wear and tear on the engine and the drive train and will shorten the life of your vehicle. You also won't have the maneuverability on the road in case you need to make a quick stop or get out of the way of another car coming at you. You could lose control of the trailer because your trailer can become the tail wagging the dog.
The tow vehicle you choose must have enough power and substance to carry the extra load and to perform at its maximum capacity. It has to be in good running condition. Depending upon the trailer you'll be towing, it doesn't particularly have to be a full sized truck, but if you want to downsize, it's extremely important to keep within the tow capacity of the vehicle and to have the proper hitch.
All vehicles are not created equally even though they may look the same. Several different vehicles of the same manufacturer may look exactly alike, but they can all have different towing capacities. Towing capacity is determined primarily by the engine size, the axle ratio, and the transmission. Every manufacturer publishes a vehicle tow guide that can be obtained at any dealership. Insist on seeing this information before you buy your vehicle. Don't take the word of a car salesman without seeing it in print. You can also find this information on the internet.
Neva Scheve is a recognized authority on horse trailer safety and author of, "The Complete Guide to Buying, Maintaining, and Servicing a Horse Trailer." You can learn more about trailer safety at EquiSpirit Horse Trailers.