TIRES... Tires have to be checked frequently with a trailer because a flat can go unnoticed on multiple axle trailers while it is being towed. Running with a flat can cause it to catch fire and burn up your rig. With multiple axles or tandem wheels it is hard sometimes to see a flat tire as the other tires are supporting the weight of the rig and the flat spot is less noticeable. A quick check can be made by "thumping" each tire with a tire iron or rod to make sure they all sound the same. Each time you gas up, walk around the trailer and give a quick check by feeling each tire with your hand. A tire that is getting low will be hotter than the rest. There is no substitute, however, for actually measuring tire pressures to make sure they are all within safe limits. This should definitely be done before each trip.

NOTE: The most common causes of tire failure are overloading and underinflation. Both result in excess flexing of the sidewall which causes heat buildup and eventual failure. Continuing to run with a flat can cause it to catch fire.

WHEELS AND LUG NUTS... Trailers have higher wheel loading than passenger cars or trucks. Tandem axles do not steer, and wheels are subjected to high twisting side loads in tight, slow turns. This causes the wheel to flex which tends to loosen wheel lug nuts over time. Always check lug nut torque before each trip. A suitable torque wrench only costs about $30 and is a worthwhile investment considering the value of your trailer.

Wheel lug nut torque is usually much higher than that specified for passenger car wheels. Check your particular trailer's recommended specifications. Most are in the 90-95 ft.-lb. range. On a new trailer, check the torque on all wheels after the first 25-50 miles of towing. Also recheck any wheel that has been removed and replaced after towing 25 to 50 miles. Do not drive a loaded trailer with a missing lug nut or damaged lug bolt.

Torquing order for various wheel lug nut patterns as suggested by a trailer manufacturer in their owner's manual. 

Wheel lug nuts are usually torqued in a "star" pattern pattern for 5- and 10-bolt wheels, crossing over to opposite sides as you work around the wheel. A "cross" pattern is used for 4-, 6- and 8-bolt wheels. Shown above are some suggested orders for tightening nuts on various bolt patterns. Using the numbers on the above diagram, a popular alternate for the 5-bolt pattern would be a 1-2-5-4-3 star pattern.

WHEEL BEARINGS... Axle wheel bearings also occasionally need attention. Feel with your hand at the hub to check for one that may be running hotter than the rest. (Be careful. If the bearing is adjusted too tight or is running without grease it can get VERY hot!) A hot bearing needs immediate attention. Most often either more grease or proper adjustment will ease the problem, but replacement may be necessary. Boat trailers are a particular source of wheel bearing problems as they are often put in and out of the water. A warm bearing that is suddenly cooled by being immersed in water tends to suck water into the inside as the air cools and shrinks. The water causes the bearings to rust and fail. Spring-loaded pressurized bearing caps are recommended to eliminate this problem. They are cheap and work great.

RECOMMENDED HITCH WEIGHT PERCENTAGES

TYPE OF TRAILER	PERCENT OF WT. ON TONGUE
Single Axle	10% minimum/15% maximum
Tandem Axle	9% to 15%
Travel Trailer	11% to 12%
5th Wheel	15% to 25%

PLACING THE LOAD

It would be overly simplistic to say, "put the heavy items over the axles". Sometimes a lot of little items can far outweigh one big one. I believe the value of an item should be one of the first considerations of where it is put in a trailer. Arrange the load so that these items are protected by their location. Don't put big, heavy items in a place where they can't be securely tied down. A glued down rug makes a great floor for a cargo trailer. Things stay put and don't slide around. Of course, it would be easy to say everything should be securely tied down but it would be also unrealistic. Start with top heavy items if you have them. That's usually a good place to start because you must have plenty of room available to properly tie them down. Tying them straight down is not secure enough. They need to be tied off at several angles or they could fall over in an abrupt change in speed or direction. You need room to accomplish this. Smaller items can be used to fill the spaces around them later.

Once you have the heavy items located, check the tongue weight . If the load is radically off, make the changes necessary to get close. The smaller items can be loaded in such a way that they balance out the load. They should be located so that they will stay put. Placing them next to items that have already been tied down helps, but your main concern should be to not lose the balance of the trailer. Don't forget you can also get one side of a trailer a lot heavier than the other without a little planning. This can cause a very serious problem when cornering, even causing the trailer to turn over in a sudden turn.

Top heavy loads can cause problems not only in cornering but also in hard braking. They have a tendency to make the trailer "dive" in hard braking conditions. This suddenly increases tongue weight and can decrease front axle loading just when you need steering and those big front disc brakes the most. Center top heavy items or arrange the remainder of the load to act as a counter weight to minimize this effect.

Top heavy loads can cause trailer "dive" under hard braking, possibly reducing steering and braking control.

Never place heavy objects on add-on devices hung on the rear bumper or placed across the tongue frame. A bicycle may be fine to hang out in back, but not a motorcycle. This places heavy objects where they will dramatically effect handling in corners or bumps. Heavy weights placed well behind the axle can also aggravate swaying in turns.

It is not possible to cover every conceivable loading or trailering situation. The best advice I can give is to use good common sense and to always allow plenty of margin for safety. The purpose is to try to give you the necessary information to make intelligent, informed decisions when loading. The ultimate responsibility for using that information correctly lies with you and you alone.

Contact Information RTM INDUSTRIES Telephone: 435-986-8474 FAX: 435-986-8482 E-mail: rtmindustriesusa@aol.com