12213 1200.01
8
DETERMINING TONGUE WEIGHT (TW)
NOTE.
Gross trailer weight (GTW) is the
actual
weight of the trailer fully loaded
(including trailer, boat, motor, fuel and accessories). Tongue weight (TW ) is
the downward force exerted on the hitch ball at the trailer coupler. In most
cases, this should be 5 to 7 percent of GTW (refer to previous Trailer
Adjustment section).
Tongue weight should be directly measured with a tongue weight scale
(shown). If unavailable, tongue weights of up to 200 Ibs. can be measured on
a household scale by resting the trailer coupler on the scale and placing the
scale on a block so that the coupler is at its normal towing height with trailer
frames level and parallel to level ground. Trailer should be towed with frames
level to parallel ground at all times.
For heavier tongue weights, place a household scale and a brick or block of
wood of equal thickness as the scale upon blocks spaced three feet apart as
shown below. 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. Lower the trailer coupler on the beam as shown, one
(1) foot from the brick or wood block and two (2) feet from the scale.
To obtain the actual tongue weight, multiply the scale reading by three (3). For
greater tongue weights, place the scale and brick or wood block four
(4) feet
apart. Lower the coupler on the beam three (3) feet from the scale, then
multiply the scale reading by four (4).
IMPORTANT NOTICE
-
I
MPROPER
TONGUE
WEIGHT
,
OR
A
TRAILER
TOWED
AT
A
FRAME
ATTITUDE
OTHER
THAN
LEVEL
AND
PARALLEL
TO
LEVEL
GROUND
,
CAN
LEAD
TO
IMPROPER
TIRE
WEAR
AND
UNSAFE
TOWING
CONDITIONS
.
Tongue Weight
Diagram
For determining
tongue weights in
excess of 200 lbs.
with a household
scale
Tongue Scale
Method
For direct
measurement to
1,000 lb.
