Trailers that include tack compartments at the back of the trailer make working out of them a snap.

We humans have been carting our horses from one place to another for 3,500 years. By some accounts, horses traveled in horse-drawn carriages, in trucks during World War II and, by the 1960s and 1970s, in trailers.

Twenty years ago, you went to the trailer dealer and purchased a small, dark, two-horse straight load with a manger in front and storage underneath. You could hitch it to the bumper of your truck and drive away.

But if your horse were larger than the average Quarter Horse or Arabian, you had to stuff him in that average 5-foot-wide and 6-foot-tall trailer. His tail might have hung out the back of the trailer, his hindquarters pressed up against the door, his hocks just barely clear of the ramp or back doors.

Horse trailers had steel roofs, and larger horses traveled with their heads in awkward positions, leading to respiratory problems. (According to research conducted much later, horses need to cough out the dust, and therefore need to be able to easily lower and raise their heads.) We closed our horses inside to protect them from the elements.

Hauling Improvements

New composite materials have made horse trailers lighter and more rust-resistant. Instead of one size for everyone, you can now get a trailer more suited to the size of your own horses. Improvements in suspension will give horses a more comfortable ride. Better ventilation and larger windows can reduce the chances of respiratory problems associated with hauling. Many trailers come with living quarters so that people can stay with their animals on the road.

Horse trailers used to be relatively inexpensive. You could easily find a little two-horse steel trailer for a couple of thousand dollars or less. Trailers were just a steel box on wheels, so the materials were inexpensive and the construction very basic. Deluxe, back then, meant having a tack compartment.

Well, how times have changed. Now trailers are made to accommodate colossal draft horses and minis, and just about every size in between. Humans can tow trailers in the biggest, most powerful truck on the market or a smallish SUV because some trailers today are made  of lighter material. Trailer owners can lounge by a gas-log fireplace in their RV-style trailers after the horse show or trail ride.

You can’t find many horse trailers that cost less than $6,000 new, but you can find plenty that reach into the upper five figures. Changes in materials, design and mechanics of horse trailers have vastly increased the number of choices for customers, and helped improve the safety and comfort of their equine passengers.

Most horse trailer companies are small and independently owned—there are more than 600 manufacturers, according to one research report—so they often don’t have their own research departments. Instead, they borrow materials and manufacturing innovations from the automotive industry, and interior and design ideas from the makers of recreational vehicles. In fact, in the newest horse trailers, you’ll see many components reminiscent of RVs, such as lightweight shells, independent torsion suspension and pop-out walls.

Materials
Twenty years ago, trailers, like cars, were made of 100% steel. Nowadays, cars have steel frames and bodies of some kind of composite material, such as a fiberglass or aluminum combination. Trailers also can be made from steel, aluminum and fiberglass, or some combination, for the same reason: Lighter materials improve gas mileage and wear and tear on vehicles, and, most importantly, they don’t rust. Remember the old family car that was slowly crumbling away? Horse trailers used to suffer the same fate.

Adding aluminum walls and shells to steel frames was one of the first major innovations in trailer construction, primarily to address the rust problem. And aluminum did take the market by storm, says Tom Sheve, co-author of The Complete Guide to Buying, Maintaining and Servicing a Horse Trailer, with his wife, Neva. The Sheves also own Equispirit Trailer Co.

The very first aluminum trailers came on the market in the late 1970s. In 1984 and ’85, Sooner, Sundowner and Equisport introduced their first aluminum trailers, Sheve says. Early aluminum tended to rip, leaving sharp edges. Over time, though, the material has improved vastly because it is mixed with components such as silicon, copper and zinc. These combinations are called aluminum alloys. They tend to be stronger than straight aluminum, can more easily withstand the abuse a horse trailer takes and are safer in an accident.

Older used trailers can be a good value, but only if they've been well cared for. Rust is the enemy of any trailer.

But be warned that even an “all-aluminum trailer” will have some steel components, such as bases and sub-frames. Combination trailers have also become a lot more popular, with manufacturers building the shell out of lightweight aluminum and the frame out of steel.

Fiberglass has also gained popularity over the past few decades. It has several advantages, but a few disadvantages as well. First, it is softer than aluminum or steel (because it’s actually a textile, rather than a metal), and it reflects rather than conducts heat. Fiberglass trailers can be pulled by less powerful vehicles. However, they also don’t have the durability of steel or steel and aluminum trailers.

A more recent innovation comes from the RV industry, which has begun fabricating some of its shells from Fiberglass Reinforced Plywood (FRP). It’s a very light material and apparently strong, and the horse-trailer industry is now using that as well.

Steel technology remains a favorite, though, because it is cheaper (although for the past couple of years the price of steel has been increasing steadily) and easier to modify and repair. Steel is still the most durable material available, and the industry has made vast improvements in rust control. Now you can find rust-resistant and coated steel products, such as Galvaneal—a steel that is heated until it becomes porous and then infused with zinc and iron. That is not the same as galvanized steel, which has a rust-proof coating.

Some steel trailers are made with different weight steels for various parts—lighter steels for the shells and heavy-gauge steels for the frames. Trailer manufacturers who use this method say the weight difference between steel trailers and aluminum is only about 15%. With today’s steel trailers, owners get the durability, safety and ease of repair of steel without yesterday’s rust problems. And although it is still heavier than aluminum or fiberglass, steel tends to hold up better in a crash.

Floorboards used to be plain old two-inch-thick wood planking (often oak or some other strong wood). Some argue that this is still the best material for floors because it is durable, easily repairable and porous, allowing manure and urine odors to dissipate quickly. (Another reason horses sometimes get respiratory disease after hauling has to do with ventilation and the accumulation of ammonia odor in enclosed trailers.)

Like steel, wood-treatment options have expanded widely, increasing the longevity and safety of the plain old wooden floor. Such innovations include pressure treating wood (often pine) to seal it against decay, or painting it with various coatings that retain the wood’s porous nature but also protect it from rotting.

Wood planks tend to still work best because wood doesn’t conduct heat the way aluminum or other metals can. (There’s a reason cooking pots are made of aluminum.) Rubber composite, called Rumbar, has become popular over the past few years, and trailer manufacturers who use it say it can eliminate the need for mats because it is soft and cushiony.

Modern trailers include plenty of tie rings as well as rounded metal edges to prevent tied horses from cutting themselves.

One Size Doesn’t Fit All
One of the most important changes over the past 20 years, though, is the size of horse trailers. Rarely more than 6 feet wide in 1975, few horse trailers today measure less than 7 feet wide. And while it doesn’t matter so much for a small horse to ride in a large trailer, the opposite almost always causes discomfort.

A market researcher who was working with specialtyvehicles.net and wrote a report for the trailer industry noted that trailers are simple structures, and that the modifications usually come from customers. When larger horses started becoming more popular, customers started demanding more custom horse trailers that were both taller and wider.

“Anyone with welding gear can make a trailer,” says Jeremy Brahm. “Horse-trailer manufacturers have listened to customers who say, ‘It’s just not wide enough for my horse.’ In the past it was one size fits all, but if one company decides to make something wider, it filters very quickly through the industry.”

Once a company finds that several customers have suggested similar modifications, it will often adopt that suggestion in the next product line. Larger trailers used to be custom requests, but now nearly every trailer manufacturer makes a larger-sized trailer. And recently, with the increased popularity of mini breeds, one manufacturer has even fashioned a mini-horse-sized trailer.

Ten Reasons to Upgrade

Rust. There could be more serious structural damage. Check the welds and the frame. Size. Your horse is stuffed in your old trailer. Tails hanging out the back are not cute—they’re dangerous. Change in towing vehicle. Did you trade your truck for a large-sized SUV? Maybe it’s time to think about trading steel for aluminum (although the difference nowadays is minimal). Ventilation. We know a lot more than we used to about horse health while traveling. The more air circulating, the better your horse will feel when he gets there. Change in location. Did you move to an area of the country with a different climate? Your stock-side trailer that worked fine in the desert Southwest might not be appropriate for hauling during a New England winter. Or vice versa: A fully enclosed, dark-colored trailer might be more solid than you need for hauling Arizona horses. Too many vehicles. You’re hauling your horse with truck and trailer while your husband drives the camper? Time to make a trade. Sell the camper and trailer and buy a reasonably priced weekender horse-trailer package. Just plain age. Sometimes it’s just time. If repairs and changes are costing you more than the value of your trailer, it’s probably time for a new one. Cost. If you are spending a lot of money on hotels, calculate the costs of room nights and restaurant meals on the road. You might be surprised to find that a trailer with living quarters makes financial sense. More members of the equine family. The rule of thumb is to have one more space than you need (a three-horse trailer if you have two horses, for example). If you need to evacuate your horses in a hurry, you don’t want to have to worry about finding one or two of them a ride. Safety. Horse trailers are structurally improved and much safer than they used to be. Even if your trailer is in pristine condition, you might owe it to your horses to consider an upgrade to a safer model.

Height, more than width, has changed drastically over the years. Jim Branch, who has been selling trailers for 20 years for S and H Trailers, says that the driving force here was the crossbreeding of the short, stocky Quarter Horse with the taller, leaner Thoroughbred, as well as the increased importation and breeding of the European horses with draft-horse type builds.

Trailers grew from 5 or 6 feet tall to 7-plus, depending on the manufacturer. More importantly, though, trailer sizes became variable. You now can find one to fit your horses, rather than cramming your horse into a one-size-fits-all model of yesterday.

Mechanicals
Axles, springs and other suspension components have become much more advanced and comfortable for equine passengers, thanks in part to engineering advancements in recreational vehicles and in cars. Older horse trailers (and less expensive ones) tend to have leaf spring or shackle suspension, in which the springs are curved together to absorb the shock. Manufacturers began installing rubber torsion suspension (a round axle inside of a square one, with the gaps filled with rubber) several years ago, which offers a smoother ride for the horse, according to Tom Sheve.

Rubber torsion means that each tire moves separately and bounces on its own natural rubber cords. Sheve says this is a quieter ride for the horses and an easier pull on the driver. However, torsion suspension is more expensive than the other two options. And if you use your trailer on dirt roads or out in fields, it can be bouncier for the horses.

Shackle springs, which are attached with hangers to the leafs, give you little independent axle movements. They are best for lighter trailers not used frequently, or those you use in bumpy terrain.

Slant or Straight?
We won’t get into the slant vs. straight debate here. We’ll leave that to the researchers at universities who study which way horses prefer to ride.

During the 1980s, trailers were straight loads, period. Gradually, slant loads began appearing on the market, mostly because customers requested the ability to carry more horses without extending the trailer length.

Four-horse trailers used to be long affairs, with two horses up front, a middle load ramp, two horses behind and a rear ramp. But engineers came up with the slant concept, and now about 80% to 90% of the larger three- and four-horse trailers sold in the U. S. are slants.

Why did straight loads go out of fashion? Some university research showed that horses traveled better when all their weight was distributed on the slant. But manufacturers contend that people wanted to pull more horses without substantially adding to the length of their trailers.

The research about horse comfort remains inconclusive. Slant-load trailers have some obvious disadvantages. For example, to get to the front horse, you have to unload the back horse — not always a safe idea. Some manufacturers have added ramps and doors to the front slant space, which makes it flexible enough for those who might want their horses to ride backwards, or who might need to unload a horse on the road. Manufacturers still make a large number of straight-load, two-horse trailers, and those may never go out of fashion.

The Air Up There
The industry has made a lot of discoveries over the years about horse trailers and what’s the healthiest way for a horse to travel. One of the most important ways trailers have improved is in the ventilation area.

Super-sized trailers have spawned super-sized trucks to pull them.

Rather than closing the doors and windows (often just sliding plastic with window screening behind it) to protect the horses from wind and weather, windows have increased in size and complexity. In addition, almost all trailers come with some kind of opening roof vents. Windows have expanded in width, from tiny 6-inch rectangles to square configurations that are much wider. They are installed with safety glass instead of Plexiglas or plastic.

Living Luxe on the Road
The single biggest trend in the past two decades in horse-trailer manufacturing is the addition of living quarters. These days you can have a trailer with a porta-potty, cowboy shower, sink, bed and air conditioner for an affordable price (called the weekender in the industry). Or you can go all out and have a fully equipped bath, kitchen, sleepers for four and even a gas fireplace.

The amenities are almost as astounding as their popularity. In the past it wasn’t unusual to find horse trailers that their owners had modified to accommodate camping. These often crude setups were more like tent camping in a steel box.

It didn’t take the trailer industry long to catch on, though, and the first production living quarters appeared on the scene a decade or so ago. Those were high-end affairs, often fabricated using manufacturers in the RV industry. Now, though, their popularity has grown so enormously that there’s a living quarters setup for nearly every budget.

You’ve Come a Long Way, Baby
Engineers have been working tirelessly to improve automobiles and their components, and along the way the horse-trailer industry has borrowed plenty of innovations. It hasn’t been left behind in price, either. From $1,500 in 1980 to $50,000 and more, horse trailers have become a major purchase. The finance industry has also evolved. Today, horse-trailer dealers have setups similar to car dealerships, where buyers can have their new horse trailer financed on the premises.

As for the future, look for the comfort and safety of horses to become the subject of more studies, and for manufacturers to continue to borrow from the car, truck and recreational vehicle industry (all substantially larger than the horse-trailer manufacturing business) for its innovations. There are plenty of reasons to purchase a newer horse trailer these days, from safer, stronger materials that protect the horse in the event of a crash, to the little extras that make life a little safer and more comfortable for people.