Consider the following example:
A vehicle model base weight is 5,500 lbs (2 495 kg);
2,800 lbs (1 270 kg) at the front axle and 2,700 lbs
(1 225 kg) at the rear axle. It has a GVWR of 7,200 lbs
(3 266 kg), a RGAWR of 4,000 lbs (1 814 kg) and a
GCWR (Gross Combination Weight Rating) of
14,000 lbs (6 350 kg). The trailer rating should be:
You can expect tongue weight to be at least 10 percent
of trailer weight (850 lbs (386 kg)) and because the
weight is applied well behind the rear axle, the effect on
the rear axle will be greater than just the weight
itself, as much as 1.5 times as much. The weight at the
rear axle could be 850 lbs (386 kg) X 1.5 = 1,275 lbs
(578 kg). Since the rear axle already weighs 2,700 lbs
(1 225 kg), adding 1,275 lbs (578 kg) brings the
total to 3,975 lbs (1 803 kg). This is very close to, but
within the limit for RGAWR as well. The vehicle is set to
trailer up to 8,500 lbs (3 856 kg).But let us say your speci c vehicle is equipped with
some of the latest options and you have a front
seat passenger and two rear seat passengers with
some luggage and gear in the vehicle as well. You may
add 300 lbs (136 kg) to the front axle weight and
400 lbs (181 kg) to the rear axle weight. Your vehicle
now weighs:
Weight is still below 7,200 lbs (3 266 kg) and you may
think that you should subtract 700 additional pounds
(318 kg) from your trailering capacity to stay within
GCWR limits. Your maximum trailer would only be
7,800 lbs (3 538 kg). You may go further and think you
must limit tongue weight to less than 1,000 lbs (454 kg) to
avoid exceeding GVWR. But, you must still consider the
effect on the rear axle. Because your rear axle now
weighs 3,100 lbs (1 406 kg), you can only put 900 lbs
(408 kg) on the rear axle without exceeding RGAWR.
4-36
ProCarManuals.com
The effect of tongue weight is about 1.5 times the actual
weight. Dividing the 900 lbs (408 kg) by 1.5 leaves you
with being able to handle only 600 lbs (272 kg) of tongue
weight. Since tongue weight is usually at least 10 percent
of total loaded trailer weight, you can expect that the
largest trailer your vehicle can properly handle is
6,000 lbs (2 721 kg).
It is important that you make sure your vehicle does not
exceed any of its ratings — GCWR, GVWR, RGAWR,
Maximum Trailer Rating or Tongue Weight. The only
way to be sure you are not exceeding any of these
ratings is to weigh your vehicle and trailer.
Total Weight on Your Vehicle’s Tires
Be sure your vehicle’s tires are in ated to the upper limit
for cold tires. You will nd these numbers on the
Certi cation/Tire label. SeeLoading the Vehicle on
page 4-22. Then be sure you do not go over the GVW
limit for your vehicle, including the weight of the
trailer tongue.
Hitches
It is important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why you will need the right hitch. Here
are some rules to follow:
The rear bumper on your vehicle is not intended
for hitches. Do not attach rental hitches or
other bumper-type hitches to it. Use only a
frame-mounted hitch that does not attach to the
bumper.
Will you have to make any holes in the body of
your vehicle when you install a trailer hitch? If
you do, then be sure to seal the holes later when
you remove the hitch. If you do not seal them,
deadly carbon monoxide (CO) from your exhaust
can get into your vehicle. SeeEngine Exhaust
on page 2-37. Dirt and water can, too.
4-37
ProCarManuals.com
Safety Chains
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer so that the tongue will not drop to
the road if it becomes separated from the hitch.
Instructions about safety chains may be provided by the
hitch manufacturer or by the trailer manufacturer.
Follow the manufacturer’s recommendation for attaching
safety chains and do not attach them to the bumper.
Always leave just enough slack so you can turn
with your rig. And, never allow safety chains to drag on
the ground.
Trailer Brakes
If you tow more than 1,000 lbs (450 kg), use trailer
brakes. Because your vehicle has antilock brakes,
do not try to tap into your vehicle’s hydraulic brake
system. If you do, both brake systems will not work
well, or at all.
Be sure to read and follow the instructions for the trailer
brakes so you will be able to install, adjust and
maintain them properly.
Driving with a Trailer
Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you will want to
get to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
4-38
ProCarManuals.com
Checking Things Under
the Hood
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing, and tools away
from any underhood electric fan.
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
Hood Release
To open the hood, do the following:
1. Pull the hood release
handle with this symbol
on it. It is located
under the instrument
panel on the driver’s
side of the vehicle.
2. At the front of the vehicle, pull up on the center of
the hood, and push the secondary hood release to
the right.
3. After you have partially lifted the hood, gas struts
will automatically take over to lift and hold the
hood in the fully open position.
Before closing the hood, be sure all ller caps are on
properly.
Pull the hood down to close. Lower the hood until the
lifting pressure of the strut is reduced. Then allow the
hood to fall and latch into place under its own weight.
Check to make sure the hood is closed. If the hood does
not fully latch, gently push the hood down at the front and
center of the hood until it is completely latched.
5-11
ProCarManuals.com
(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 60, as
shown in item C of the illustration, it would mean
that the tire’s sidewall is 60 percent as high as
it is wide.
(D) Construction Code
:A letter code is used to
indicate the type of ply construction in the tire. The
letter R means radial ply construction; the letter D
means diagonal or bias ply construction; and the
letter B means belted-bias ply construction.
(E) Rim Diameter
:Diameter of the wheel in
inches.
(F) Service Description
:These characters
represent the load range and speed rating of the
tire. The load index represents the load carry
capacity a tire is certi ed to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certi ed to carry
a load. Speed ratings range from A to Z.
Tire Terminology and De nitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of the
tire. Air pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of a tire’s height
to its width.
Belt
:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
5-53
ProCarManuals.com
Bias Ply Tire:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.
Cold Tire Pressure
:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. SeeInflation - Tire Pressure on
page 5-56.
Curb Weight
:The weight of a motor vehicle with
standard and optional equipment including the
maximum capacity of fuel, oil, and coolant,
but without passengers and cargo.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identi cation Number (TIN), an
alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
GVWR
:Gross Vehicle Weight Rating.
SeeLoading the Vehicle on page 4-22.GAWR FRT
:Gross Axle Weight Rating for the
front axle. SeeLoading the Vehicle on page 4-22.
GAWR RR
:Gross Axle Weight Rating for the
rear axle. SeeLoading the Vehicle on page 4-22.
Intended Outboard Sidewall
:The side of an
asymmetrical tire, that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric unit for air pressure.
Light Truck (LT-Metric) Tire
:A tire used on
light duty trucks and some multipurpose passenger
vehicles.
Load Index
:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum In ation Pressure
:The maximum
air pressure to which a cold tire can be in ated.
The maximum air pressure is molded onto the
sidewall.
Maximum Load Rating
:The load rating for a tire
at the maximum permissible in ation pressure
for that tire.
5-54
ProCarManuals.com
Maximum Loaded Vehicle Weight:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight.
Normal Occupant Weight
:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). SeeLoading the Vehicle on
page 4-22.
Occupant Distribution
:Designated seating
positions.
Outward Facing Sidewall
:The side of an
asymmetrical tire that has a particular side that
faces outward when mounted on a vehicle.
The side of the tire that contains a whitewall,
bears white lettering, or bears manufacturer,
brand, and/or model name molding that is higher
or deeper than the same moldings on the other
sidewall of the tire.
Passenger (P-Metric) Tire
:A tire used on
passenger cars and some light duty trucks and
multipurpose vehicles.
Recommended In ation Pressure
:Vehicle
manufacturer’s recommended tire in ation
pressure as shown on the tire placard.
SeeInflation - Tire Pressure on page 5-56
andLoading the Vehicle on page 4-22.Radial Ply Tire
:A pneumatic tire in which
the ply cords that extend to the beads are laid
at 90 degrees to the centerline of the tread.
Rim
:A metal support for a tire and upon which
the tire beads are seated.
Sidewall
:The portion of a tire between the tread
and the bead.
Speed Rating
:An alphanumeric code assigned to
a tire indicating the maximum speed at which a
tire can operate.
Traction
:The friction between the tire and the
road surface. The amount of grip provided.
Tread
:The portion of a tire that comes into
contact with the road.
Treadwear Indicators
:Narrow bands, sometimes
called wear bars, that show across the tread of
a tire when only 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires
on page 5-64.
5-55
ProCarManuals.com
UTQGS (Uniform Tire Quality Grading
Standards):A tire information system that
provides consumers with ratings for a tire’s
traction, temperature, and treadwear. Ratings
are determined by tire manufacturers using
government testing procedures. The ratings are
molded into the sidewall of the tire. SeeUniform
Tire Quality Grading on page 5-68.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. SeeLoading
the Vehicle on page 4-22.
Vehicle Maximum Load on the Tire
:Load on
an individual tire due to curb weight, accessory
weight, occupant weight, and cargo weight.
Vehicle Placard
:A label permanently attached
to a vehicle showing the vehicle’s capacity
weight and the original equipment tire size
and recommended in ation pressure.
See “Tire and Loading Information Label”
underLoading the Vehicle on page 4-22.
In ation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-in ation or over-in ation is all right.
It is not. If your tires do not have enough air
(under-in ation), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-in ation),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazards
5-56
ProCarManuals.com