Noise Control System
Tampering with Noise Control
System Prohibited
The following information relates to compliance
with federal noise emission standards for vehicles
with a Gross Vehicle Weight Rating (GVWR) of
more than 10,000 lbs (4 536 kg). The Maintenance
Schedule provides information on maintaining
the noise control system to minimize degradation
of the noise emission control system during
the life of your vehicle. The noise control system
warranty is given in your warranty booklet.
These standards apply only to vehicles sold in the
United States.Federal law prohibits the following acts or the
causing thereof:
1. The removal or rendering inoperative by
any person, other than for purposes of
maintenance, repair or replacement, of any
device or element of design incorporated into
any new vehicle for the purpose of noise
control, prior to its sale or delivery to the
ultimate purchaser or while it is in use; or
2. The use of the vehicle after such device or
element of design has been removed or
rendered inoperative by any person.
Among those acts presumed to constitute
tampering are the acts listed below.
Insulation:
Removal of the noise shields or any
underhood insulation.
Engine:
Removal or rendering engine speed governor,
if the vehicle has one, inoperative so as to
allow engine speed to exceed manufacturer
speci cations.
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(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the light truck (LT-Metric) tire
illustration, it would mean that the tire’s sidewall is
75 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:The service description
indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
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/
transaxle, 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.
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.
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