Get Wheels and tires -> Definition of terms for tires and loading Guide for Mercedes GLC Class SUV First generation (2015-2021)

476 Wheels and tires

All-weather tires and winter tires

"C", "D", "E": a load range that depends on

the maximum load that the tire can carry at a

certain pressure

Index

ZR...Y¹

ZR...(..Y)¹

ZR¹

Speed rating

Index

Speed rating

up to 186 mph (300 km/h)

over 186 mph (300 km/h)

over 149 mph (240 km/h)

Q M+S²

T M+S²

H M+S²

V M+S²

up to 100 mph (160 km/h)

up to 118 mph (190 km/h)

up to 130 mph (210 km/h)

up to 149 mph (240 km/h)

Definition of terms for tires and loading

Tire structure and characteristics: describes

the number of layers or the number of rubber-

coated belts in the tire contact surface and the

tire wall. These are made of steel, nylon, poly‐

ester and other materials.

Bar: metric unit for tire pressure.

14.5038 pounds per square inch (psi) and

100 kilopascal (kPa) is the equivalent of one bar.

DOT (Department of Transportation): DOT-

marked tires fulfill the requirements of the

US Department of Transportation.

Average weight of the vehicle occupants: the

number of vehicle occupants for which the vehi‐

cle is designed, multiplied by 150 lb (68 kg).

Specifying the speed rating as the "ZR" index

in tire code 4 is optional for tires up to

186 mph (300 km/h).

If your tire code 4 includes "ZR" and there

is no speed rating 7, find out what the max‐

imum speed is from the tire manufacturer.

If load-bearing index 6 and speed rating 7

are in brackets, the maximum speed rating of

your tire is above 186 mph (300 km/h). To

find out the maximum speed, ask the tire

manufacturer.

Winter tires bear the i snowflake symbol

and fulfill the requirements of the Rubber Manu‐

facturers Association (RMA) and the Rubber

Association of Canada (RAC) regarding the tire

traction on snow.

Load index 8:

No specification given: standard load (SL)

tire

"XL" or "Extra Load": extra load tire or rein‐

forced tire

"Light Load": light load tire

"ZR" stated in the tire code.

Or "M+S i" for winter tires

Wheels and tires 477

Uniform Tire Quality Grading Standards: a

uniform standard to grade the quality of tires

with regard to tread quality, tire traction and

temperature characteristics. The quality grading

assessment is made by the manufacturer follow‐

ing specifications from the U.S. government. The

quality grade of a tire is imprinted on the side

wall of the tire.

Recommended tire pressure: the recommen‐

ded tire pressure is the tire pressure specified

for the tires mounted to the vehicle at the fac‐

tory.

The tire and information table contains the rec‐

ommended tire pressures for cold tires, the max‐

imum permissible load and the maximum per‐

missible vehicle speed.

The tire pressure table contains the recommen‐

ded tire pressures for cold tires under various

operating conditions, i.e. loading and/or speed

of the vehicle.

regardless of whether it is actually installed on

the vehicle or not.

Rim: the part of the wheel on which the tire is

installed.

of the fully laden vehicle (weight of the vehicle

including all accessories, occupants, fuel, lug‐

gage and the trailer drawbar noseweight if appli‐

cable). The gross vehicle weight rating is speci‐

fied on the vehicle identification plate on the

B‑pillar on the driver's side.

Maximum weight of the laden vehicle: the

maximum weight is the sum of the curb weight

of the vehicle, the weight of the accessories, the

maximum load and the weight of optional equip‐

ment installed at the factory.

Kilopascal (kPa): metric unit for tire pressure.

6.9 kPa corresponds to 1 psi. Another unit for

tire pressure is bar. 100 kilopascal (kPa) equals

1 bar.

Load index: in addition to the load-bearing

index, the load index may also be imprinted on

the side wall of the tire. This specifies the load-

bearing capacity of the tire more precisely.

GAWR (Gross Axle Weight Rating): the GAWR

is the maximum permissible axle load. The

actual load on an axle must never exceed the

gross axle weight rating. The gross axle weight

rating can be found on the vehicle identification

plate on the B‑pillar on the driver's side.

Speed rating: the speed rating is part of the tire

identification. It specifies the speed range for

which a tire is approved.

GVW (Gross Vehicle Weight): the gross vehicle

weight comprises the weight of the vehicle

including fuel, tools, the spare wheel, accesso‐

ries installed, occupants, luggage and the trailer

drawbar noseweight, if applicable. The gross

vehicle weight must not exceed the gross vehicle

weight rating GVWR as specified on the vehicle

identification plate on the B‑pillar on the driver's

side.

Curb weight: the weight of a vehicle with stand‐

ard equipment including the maximum capacity

of fuel, oil and coolant. It also includes the air

conditioning system and optional equipment if

Increased vehicle weight due to optional

equipment: the combined weight of all standard

and optional equipment available for the vehicle,

GVWR (Gross Vehicle Weight Rating): the

GVWR is the maximum permitted gross weight

478 Wheels and tires

these are installed on the vehicle, but does not

include passengers or luggage.

without direct sunlight on the tires or the vehicle er's identity code, tire size, tire type code and

has been driven for less than 1 mile (1.6 km).

the manufacturing date.

Maximum tire load: the maximum tire load is

Tire contact surface: the part of the tire that

Load-bearing index: the load-bearing index is a

code that contains the maximum load-bearing

capacity of a tire.

the maximum permissible weight in kilograms or comes into contact with the road.

lbs for which a tire is approved.

Maximum permissible tire pressure: maxi‐

mum permissible tire pressure for one tire.

Maximum load on one tire: maximum load on

one tire. This is calculated by dividing the maxi‐

mum axle load of one axle by two.

PSI (pounds per square inch): standard unit of

measurement for tire pressure.

Tire bead: the purpose of the tire bead is to

ensure that the tire sits securely on the wheel

rim. There are several wire cores in the tire bead tion between the tires and the road surface.

to prevent the tire from changing length on the

wheel rim.

Side wall: the part of the tire between the tread

and the tire bead.

Weight of optional equipment: the combined

weight of the optional equipment weighing more

than the replaced standard parts and more than

5 lbs (2.3 kg). This optional equipment, such as

high-performance brakes, level control system, a

roof luggage rack or high-performance batteries,

is not included in the curb weight and the weight

of the accessories.

TIN (Tire Identification Number): a unique

identification number which can be used by a

tire manufacturer to identify tires, for example,

in a product recall, and thus identify the pur‐

chasers. The TIN is made up of the manufactur‐

Traction: traction is the grip resulting from fric‐

Wear indicator: narrow bars (tread wear bars)

that are distributed over the tire contact surface.

If the tire tread is level with the bars, the wear

limit of 1/16 in (1.6 mm) has been reached.

Distribution of vehicle occupants: distribution

of vehicle occupants over designated seat posi‐

tions in a vehicle.

Maximum permissible payload weight: nomi‐

nal load and luggage load plus 150 lb (68 kg)

multiplied by the number of seats in the vehicle.

Aspect ratio: ratio between tire height and tire

width in percent.

Tire pressure: pressure inside the tire applying

an outward force to every square inch of the tire.

The tire pressure is specified in pounds per

square inch (psi), in kilopascals (kPa) or in bar.

The tire pressure should only be corrected when

the tires are cold.

Cold tire pressure: the tires are cold when the

vehicle has been parked for at least 3 hours

Wheels and tires -> Definition of terms for tires and loading for Your Mercedes GLC Class SUV First generation (2015-2021)

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