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For The Trailer:
Gross trailer weight (GTW) is the weight of the trailer fully loaded
in its actual towing condition.
GTW is measured by placing the fully loaded trailer on a vehicle
scale. The entire weight of the trailer should be supported on the
scale as shown in Figure 1.
Tongue weight (TW) is the downward force exerted on the hitch ball by
the trailer coupler. In most cases, it is about 10 to 15 percent of
GTW. TW of up to 300 lbs. can be measured on a household scale by
resting the trailer coupler on the scale and placing the scale on a
box so that the coupler is at its normal towing height. The trailer
must be fully loaded and level.
For heavier tongue weights, place a household scale and a brick that's
as thick as the scale three feet apart as shown in Figure 2. Set a
length of pipe on each and rest a beam across the pipes. Re-zero the
scale to correct for the weight of the beam and pipe. Securely block
the trailer wheels. Rest the trailer jack on the beam as shown, one
(1) foot from the brick and two (2) feet from the scale.
To obtain the TW, multiply the scale reading by three (3). For greater
tongue weights, place the scale and brick four (4) feet apart, rest
the jack on the beam three (3) feet from the scale and multiply the
scale reading by four (4).
For The Tow Vehicle:
Like the trailer, the tow vehicle has a maximum weight capacity it was
designed to tow. Its maximum towing capacity can be found in the
owner's manual.
YOUR TOWING EQUIPMENT
TRAILER HITCHES, RECEIVERS AND BALL MOUNTS
Select these products by their gross trailer weight and tongue
weight ratings. Select hitches and receivers for specific vehicles.
HITCH BALLS
Select by gross trailer weight rating, mounting platform thickness
and hole size, and coupler socket size Platform must be
at least 3/8 inch thick. Hole must not exceed threaded shank
diameter by more than 1/16 inch. Use lock washer. Tighten per
instructions. When tightened, shank must protrude beyond
bottom of nut. Gross trailer weight rating and ball diameter are
marked on DRAW-TITE balls.
TRAILER COUPLERS
The coupler socket should be smooth, clean and lightly lubricated.
Tighten or adjust per coupler manufacturer's instructions.
SAFETY CHAINS
Connect safety chains properly EVERY TIME YOU TOW. Cross
chains under coupler. Attach securely to the hitch or tow vehicle
so they can't bounce loose. Leave only enough slack to permit
full turning. Too much slack may prevent chains from maintaining
control if other connections separate. Don't let chains drag
on the road.
TRAILER LIGHTS, TURN SIGNALS, ELECTRIC BRAKES
AND BREAK AWAY SWITCH CONNECTIONS
Make these safety-critical connections EVERY TIME YOU TOW,
no matter how short the trip. Check operation, including electric
brake manual control, before getting on the road.
SWAY CONTROLS
Sway controls can lessen the effects of sudden maneuvers,
wind gusts and buffeting caused by other vehicles. We recommend
them for trailers with large surface areas, such as travel
trailers. Adjustable friction models can help control trailers with
low tongue weight percentage.
OTHER USEFUL EQUIPMENT
AIR SPRINGS, AIR SHOCKS or HELPER SPRINGS are useful
for some hitch applications. A TRANSMISSION COOLER may
be necessary for heavy towing. Many states require TOWING
MIRRORS on both sides.
TIRE INFLATION
Check often. Follow tow vehicle and trailer manufacturers' recommendations.
Improper tire inflation can cause trailer sway.
CHECK YOUR EQUIPMENT / REPLACE WORN PARTS
Check ball, coupler, chains, retaining pins and clips, and all
other connections EVERY TIME YOU TOW. Re-check at fuel
and rest stops.
SAFE TOWING TIPS
NO PASSENGERS IN TRAILERS!
Never allow people in trailers while towing, under any circumstances.
TRAILER LOADING
Proper loading helps prevent sway. Place heavy objects on the
floor ahead of the axle. Balance the load side-to-side. Secure it to
prevent shifting. Tongue weight should be 10-15 percent of gross
weight for most trailers. Too low a percentage of tongue weight can
cause sway. NEVER load the trailer rear-heavy. LOAD THE TRAILER
HEAVIER IN FRONT.
DRIVING
The additional weight of a trailer affects acceleration, braking and
handling. Allow extra time for passing, stopping and changing
lanes. Severe bumps can damage your towing vehicle, hitch and
trailer. Drive slowly on rough roads. STOP AND MAKE A THOROUGH
INSPECTION IF ANY PART OF YOUR TOWING SYSTEM
STRIKES THE ROAD. CORRECT ANY PROBLEMS BEFORE
RESUMING TRAVEL
CHECK FOR EXCESSIVE SWAY AND ELIMINATE IT
Excessive sway can lead to loss of control. Sway motion should
settle out quickly. Sway tends to increase on a downgrade. Starting
slowly, increase speed in gradual steps. If sway occurs, adjust your
trailer load and equipment. Repeat until the trailer is stable at
highway speed. Do this whenever your trailer loading changes.
IF YOUR TRAILER SUDDENLY STARTS TO SWAY
Turbulence from another vehicle, a wind gust, or a downgrade can
cause sudden sway. So can a shift of the trailers load or a trailer
tire blowout. IF THE TRAILER SWAYS, IT IS THE DRIVER'S
RESPONSIBILITY TO ASSESS THE SITUATION AND TAKE
APPROPRIATE ACTION. Below are suggestions that may apply,
depending on conditions:
DO
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Reduce your speed gradually.
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Hold the steering wheel as steady as possible.
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If your trailer has electric brakes, apply the trailer brakes alone,
without using the tow vehicle's brakes
DON'T
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Don't hit your brake pedal hard unless absolutely necessary. A
"jackknife" can result.
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Don't try to steer out of the sway condition. Sudden or violent
steering can make it worse.
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Don't speed up. Sway increases as you go faster.
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Don't continue towing a trailer that tends to sway. You may lose
control during an emergency maneuver or if the conditions listed
above occur.
DON'T OVERLOAD ANY PART OF YOUR TOWING SYSTEM.
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