Stock Trailers, Flatbed Trailers, Utility Trailers and More

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A hydraulic-dump trailer is great for hauling grain or sand, and it will handle anything you'd toss in the back of your pickup.
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Hauling is such a part of the horsey life, you might as well have great equipment.
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Table of Automotive Engineers trailer hitch classes.

This buyers guide tells you what you need to know about stock trailers, flatbed trailers and utility trailers. 

Humans have been using wheeled vehicles for transport since at least 400 BC, and they have been arguing about how to back them up ever since.

Initially, people pulled or pushed those carts and wagons, but they soon discovered that beasts could relieve their burden. Today, automobiles and trucks have replaced the buggies and drays once used for travel and freighting, but our need for towing is as keen as it has ever been. Take a glance at any American highway and you will see road tractors pulling freight-laden semi-trailers, families with their earthly possessions packed in moving trucks with cars in tow, pickup trucks attached to stock trailers taking live loads to market, and more.

For farmers, trailers are a matter of economy and efficiency because we all need to move machines, animals and bulk materials. Trailers add value and possibilities to any tow vehicle, but they also add liabilities and responsibilities. Towing isn’t quite as simple as latching a trailer to your truck and heading down the road, but it isn’t neurosurgery either. With a little forethought and consideration anyone who is comfortable behind the wheel of a motor vehicle can master the ancient art of towing.

Choosing the Right Stock Trailers, Flatbed Trailers and Utility Trailers

For hauling livestock, you can choose a general-purpose stock trailer to haul everything from draft horses to pygmy goats, but there are also highly specialized models designed for one animal species. Ranchers often choose a general purpose pipe-and-panel stock trailer with at least one fore-aft partition to haul everything from calves to the whole remuda. Those trailers can easily handle a small tractor with implements and also move the teenager off to college (you might want to clean it first, depending on your teen). Specialized hog and sheep haulers are more tightly enclosed with a lower overall height, while some completely enclosed, specialized horse haulers offer fully equipped stalls and an air-conditioned tack/dressing room.

The open-deck flatbed trailer is perfect for moving machinery or various types of bulk freight like lumber and can be loaded from virtually any angle. These handy haulers come with plenty of load-securing attachment points for chains and binder straps, and regularly spaced stake pockets, which can be used for attaching removable side panels for added versatility. Some flatbed owners build removable compartments for livestock or dry freight and use the stake pockets to keep them in place.

Hydraulic-dump trailers are useful for hauling bulk materials such as feed, grain, manure, gravel, mulch and sand, but they are useful for much more than that. Many dump trailers can also accommodate a small tractor or utility vehicle and can certainly be used to haul anything that you might think of tossing into the bed of your pickup — like firewood or a water tank. Probably not the teen on his way to college, however.

Utility trailers are generally lighter duty vehicles, but they can be used on the farm. Smaller models are suitable for hauling lawn and garden tractors or other light materials such as bagged mulch. Larger models may accommodate larger-sized payloads, however, the relatively inexpensive utility trailer ought never be substituted when a heavier-duty flatbed is needed, regardless of the utility trailer’s size.

Calculate Your Trailer’s Capacity

The inexperienced often assume that size is all that matters in choosing a trailer, when in actuality weight is more important. Consider an economy 16-foot tagalong (the kind with the hitch at the rear of the tow vehicle) livestock trailer with a 5,000-pound gross towed weight rating (GTWR). While it might have room inside for four 1,500-pound bulls, simple math lets you know that you can’t haul 6,000 pounds of bull at once. So how much bull can you really haul?

The stock trailer’s 5,000-pound GTWR includes the combined weight of the trailer and the cargo. The trailer weighs 2,500 pounds clean and empty, so its payload capacity is 2,500 pounds. Or is it? The trailer’s GTWR is based on the capacity of its axles, and to some extent, its framework, but what about wheels and tires? Our test-case trailer has a pair of axles under it, each with a 2,500-pound gross axle weight rating (GAWR). But a quick glance at the tire sidewalls show that they are rated for 1,000 pounds each.

Four 1,000-pound rated tires brings the trailer’s actual GTWR down to 4,000 pounds, which leaves enough capacity to haul one of the 1,500-pound bulls after deducting the 2,500-pound weight of the trailer. If the trailer is full of manure or caked with snow or ice, there isn’t enough capacity to haul even one bull.

These calculations change some with weight transfer hitches since the tow vehicle carries part of the trailer’s GTWR. For example a 14,000-pound GTWR flatbed trailer with a gooseneck hitch might have a pair of 6,400-pound GAWR axles under it. This trailer is designed to transfer 1,200 pounds or more to the tow vehicle so the 12,800 pounds of axle capacity is plenty adequate. But when fully loaded, at least 1,200 pounds of the trailer’s gross weight is borne by the tow rig to avoid overloading the trailer’s axles. You will need to be certain the truck can handle the additional 1,200 pounds of effective payload without being overloaded.

How do you know whether your tow vehicle is suited to a specific trailer? Small cars rated for towing might be able to pull 1,000 pounds or less, while dually pickups might handle over 12,000 pounds. Motor vehicle manufacturers provide a gross combination vehicle weight rating (GCVWR) for their tow-approved cars and trucks, which is defined as the combined weight of the loaded trailer and truck when hitched together. The GCVWR is often less than the truck’s gross vehicle weight rating (GVWR) added to the trailer’s GTWR. A pickup with a 9,600-pound GVWR (be sure to check tire capacities, too) hitched to a trailer with a 12,000-pound GTWR probably won’t have a 21,600-pound GCVWR – more like 18,000 pounds depending on the truck and its equipment. The truck is still a good match for the trailer, but the GCVWR sets the upper weight limit for total payload. If the truck isn’t loaded to 9,600 pounds, then more weight can be placed on the trailer.

Getting Your Trailer Hitched

Trailer attaching systems include a hitch and mount for the tow vehicle, and a matching coupler on the trailer’s tongue. If you tow with a pickup, frame-attached hitch mounts are typically located ahead of the rear axle (gooseneck and fifth-wheel) or behind it (tagalong). In many cases, the pickup’s rear bumper is rated as a hitch mount, and many farm trailers are coupled to balls bolted to the bumper’s center. Most vans and larger SUVs can be equipped with hitch mounts attached to the frame behind the rear axle; some also have rear bumpers with rated towing capacity.

The hitch receiver is an ideal mount when the same tow vehicle is used with several different hitch sizes and styles. The receiver consists of superstructure mounted to the vehicle’s frame, which locates a 2-inch square steel socket centered beneath the rear bumper. The socket is designed to receive different hitches, which are pinned into the socket and can be quickly swapped or removed when not towing.

The most commonly encountered hitch systems utilize a ball on the tow vehicle matched to a socket coupler on the trailer’s tongue and all have a specific weight rating (Table 1). Lighter-duty tagalong hitches are generally rated for trailer tongue weights of less than 500 pounds, which many tow vehicles’ rear GAWR can readily bear. Weight distribution attachments, required for towing tagalong Class IV and heavier unclassified trailers (check tow vehicle specs), apply leverage across the hitch and place some of the trailer’s load on the tow vehicle’s front axle to keep tongue weights within specification. Other heavy-duty tagalong trailers might be equipped with a ring-shaped coupler (lunette eye) — a pintle hook on the truck is required to make that hitch. (See automotive table in the image gallery.)

When routinely towing heavier or longer loads, gooseneck or fifth-wheel systems are ideal. These heavy-duty hitches are often rated for 25,000 pounds GTWR or more (most pickups can’t legally or safely tow that weight), and when located ahead of the truck’s rear axle, they proportion the load to the front axle. The gooseneck system consists of a 25/16-inch diameter ball located in the truck’s bed, but attached to its frame through a heavy-duty mount, and a large socket coupler built into the trailer. The hitch ball supports the gooseneck’s tongue, while the socket coupler retains it.

The fifth-wheel system consists of a slotted plate (fifth wheel) with retaining latch located in the pickup’s bed (solidly attached to the truck’s frame) and a kingpin coupler on the trailer. The fifth-wheel’s latch retains the kingpin, while the trailer’s tongue weight is supported by the fifth wheel itself. This hitching system is found on every semi-trailer tractor combination on the highways today, except auto transports and mobile-home toters.

Once the truck and trailer are physically connected, they need also to share an electrical system so that, at the very least, all required lights on both vehicles operate together. This coupling is accomplished with any number of standard plug and socket combinations; use an adapter when plug and socket don’t match.

Higher GTWR trailers are often equipped with electric brakes, or electrically actuated hydraulic brakes. Power for these braking systems comes from the tow vehicle’s electrical socket via an inertia-sensing brake controller that keeps them in sync with the tow vehicle’s brakes. Hit the brake pedal hard, and the trailer brakes will be applied rapidly and with more force than when tapping the brake pedal lightly. Most controllers also allow manual trailer brake activation and power adjustment to accommodate different loads.

Trailer Load Control

Each trailer’s GTWR is based on an evenly distributed, idealized, maximal payload, which is easy to achieve with grain in a dump trailer, but not so easy with sheep in a livestock trailer. Bear this in mind as you load any trailer, and do your best to distribute the weight as evenly as possible. Static loads are more predictable and therefore generally safer, so if at all possible confine livestock or liquids so that their movement is limited and has minimal affect on the trailer’s tongue weight or attitude. Loading dry goods into an enclosed trailer can be accomplished with careful packing, but it is prudent to strap portions of that load to the trailer’s floor or walls to avoid shifting.

Securing freight on a flatbed is an absolute must – even if it is just a load of hay. If you intend to haul your 6,000-pound tractor you should have at least four 3/8-inch Grade 43 chains and appropriately rated tighteners (load-binders) securing it to the trailer to comply with Federal Department of Transportation rules. Grade 70 chain and binders would be better, but they are more expensive. If the tractor has a loader on it, the loader must also be chained or strapped to the trailer. Substitute weight-rated straps for chains and binders when there is no danger that they will be cut by abrasive vibration. State and Federal DOT load-binding rules continuously evolve – check your state DOT’s regulations at least once a year. Exceeding the binding system’s weight rating is a sure way to earn an expensive ticket or huge liability damages if they fail – even in an accident that isn’t your fault.

Trailer tongue weight should be approximately 10 percent of a trailer’s loaded weight. This is particularly critical for tagalong trailers since goosenecks and fifth-wheels are designed with an unladen tongue weight approaching 10 percent of the GTWR. Moving freight forward increases the tongue weight, while moving it behind the rear trailer axle can cause a negative tongue weight and overload the axle. Negative tongue weight causes tow vehicle instability. Too much tongue weight can overload the truck’s rear axle and lighten its front end enough to make steering difficult.

Oscar “Hank” Will has pulled a variety of trailers over thousands of road and farm-lane miles carrying hay, cattle, grain, lumber, machinery, water, firewood and even his children’s household goods. He installs his own hitches, maintains his own trailers, secures his own loads and takes towing safety seriously.

Hank Will raises hair sheep, heritage cattle and many varieties of open-pollinated corn with his wife, Karen, on their rural Osage County, Kansas farm. His home life is a perfect complement to his professional life as editor in chief at GRIT and Capper’s Farmer magazines. Connect with him on .

Published on Nov 1, 2006

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