Reading Tyre

Being able to read and comprehend the information printed on a tire's sidewall will make it easier for you to understand your tires and assist you in choosing a replacement set.




Tire Sizing System
Custom or Alloy Wheels
While custom or alloy wheels require an increased level of care over steel wheels, it is vitally important that each customer receives the highest level of service. There are several key points to note when mounting Shinco tires. Following these basic precautions yields consistent results.
  Alpha-Numeric Sizing System
In 1968, a new concept was introduced worldwide. The Alpha-Numeric sizing system is a load-based system where tires are designated by their load-carrying capacity and aspect ratio. The first letter is the load and size relationship, with letters ranging from A to N. The lower the letter, the smaller the size and, of course, the lower the load-carrying capacity of the tire.
  P-Metric Sizing System
To accommodate the smaller tires used on compact cars, the P-Metric (Passenger Metric) system was created in 1976. The maximum inflation pressures of P-Metric tires were raised for lower rolling resistance. The P-Metric system is widely used by domestic tire manufacturers.
  Custom or Alloy Wheels
Because Europe primarily uses the metric system of measurement, the metric sizing system was developed. It is essentially a conversion of the Numeric system. Section widths are notated in millimeters instead of inches. Originally, tires not identified with an aspect ratio were assumed to be 82-series. When 60- and 70 series tires appeared, the aspect ratio was added to the nomenclature, similar to the P-Metric system.
SO Metric Sizing System
International Standards Organization (ISO) Metric system combines the Metric system with a service description. The service description provides the load index along with the speed rating symbol.
  Millimetric Sizing System
The Millimetric sizing system is similar to the Metric system except that the rim diameter is also represented in millimeters.
  Light Truck Numeric System
Similar to the Numeric system for cars, it lists the section width in inches, construction type, rim diameter in inches, plus the light truck designation.
  Light Truck Metric Sizing System
Similar to the P-Metric system, except the P is replaced with the LT light truck designation. Also, LT-Metric and P-Metric tires differ in construction
Light Truck High Flotation System
The same as the Light Truck Numeric system with tire diameter added to the front.

High Flotation vs. LT-Metric vs. LT-Numeric
As the size dimensions increase, Flotation-sized tires will have wider overall width than their LT-Metric and LT-Numeric designed counterparts. Another difference is the Flotation sizes typically require wider wheel widths than LT-Metric and LT-Numeric sizes.

  Size Designation Actual Dimensions (in.)
overall diameter x overall width
High Flotation 30 x 9.5R15 29.8 x 9.6
LT-Metric LT235/75R15 29.2 x 9.3
LT-Numeric 7.00R15LT 30.3 x 8.1
Often referred to as the profile or series, the aspect ratio of a tire is determined by dividing a tire's section height by its section width when the tire is: inflated to maximum air pressure, mounted on the approved measuring rim, and under no load.

A tire with a lower aspect ratio responds to lateral force more effectively than a tire with a higher aspect

ratio. The aspect ratio affects steering stability. Generally, the shorter the sidewall, or the lower the aspect ratio, the less time it takes to transmit the steering input from the wheel to the tread. The result is quicker steering response. Aspect ratio also affects the tread contact patch. As a rule, a low profile tire produces a wider tread contact patch. This wider tread contact patch creates a stiffer footprint that reduces distortion and provides improved cornering traction. Aspect ratio also impacts ride. A low profile tire usually has a stiffer ride than the standard aspect ratio of 75 or more.










Speed rating and Load-Carrying Capacity

Service Description
Many tires come with a service description added onto the end of the tire's size. These service descriptions contain a two-digit number (load index) and a letter (speed rating). The load index is a representation of the maximum load each tire is designed to support. Because the maximum tire load-carrying capacity is branded on the tire's sidewall, the load index is used as a quick reference.

Repair of Speed-Rated Tires
Because the tire manufacturer cannot monitor the quality of the repairs for speed-rated tires, once such a tire is repaired for any reason, that area ultimately diminishes the tire's designated speed rating. This applies to Shinco tires with ratings of "N" or higher. Although the warranty will cover warrantable conditions unrelated to the repair area, the tire no longer is representative of its original manufactured condition because it has been altered. As a result, the speed rating of the tire is void after repairs have been performed. The tire is capable of running at normal sustained highway speeds up to 85 MPH if repairs are made following RMA Standards. Punctures and nail holes up to 1/4 inch diameter which are confined to the tread area may be patched permanently only from the inside of the tire along with filling the perforation of the tread caused by the nail. NEVER REPAIR TIRES WORN BELOW 2/32 INCH TREAD DEPTH. Some OE vehicle manufacturers do not allow repairs of any kind.

Repair of Run-Flat Tires
Advan Sport ZPS Run-Flat tires are not to be repaired following an injury. The tire will be replaced on a prorated basis under the terms of the limited warranty for AVS Sport Run-Flat tires. Never mix Run-Flat tires with tires that do not have Run-Flat technology. Never mix Run-Flat tires with different brands or technologies.


Use the following chart to determine the maximum load-carrying capacity based on a tire's load index:


Replacement Guidelines for Speed-Rated Tires

When replacing a tire designated with a speed rating, the new tire's speed rating should be equal or higher than the tire speed rating of the OE placard. This rule is to avoid conflicting tire speed capabilities and the possibility of misapplication, particularly because one tire may be constructed to perform under a higher speed than another. If tires with different speed ratings are mounted on the same vehicle, the lowest speed rated tire dictates the maximum vehicle speed.


Speed Rating

Speed ratings are certified maximum sustained speed designations assigned to passenger car radials and high performance tires. Because of the evolution of high-speed passenger car travel, it was necessary to establish a way to rate a tire's high-speed capability. In the U.S., these ratings are based on tire testing in laboratory conditions under simulated loads. For a tire to be speed rated, it must meet certain minimum industry standards for reaching and sustaining that specified speed. Domestically, high performance tires typically are speed rated. Shinco defines high performance tires with a speed symbol of "H, Q, V, W, Y," or "Z". Speed symbols may currently be marked on a tire in any of three ways: 205/60ZR15; 205/60ZR15 89W; or 205/60R15 89W. The International Standard Organization (ISO) system currently serves as a worldwide standard for tire markings. At the end of a transition period, any speed symbol denoting a fixed maximum speed capability will be at the end of the service description following the tire marking (illustrated in the second and third examples above).

The Tire Industry Safety Council bulletin says:
"A reasonable person realizes that driving speeds are dictated by many factors, particularly such things as the weather, road surface and mechanical condition of the vehicle. These tire symbols do not mean that motorists can drive safely at the maximum speed for which the tire is rated or in excess of the posted speed limits."

If tires with different speed ratings are mounted on the same vehicle, the tire with the lowest rating will dictate safe maximum vehicle speed.

Speed Symbols

Speed Symbol (MPH) (KPH) Open Ended Speed Category
Q 99 160  
S 112 180  
T 118 190  
U 124 200  
H 130 210 Z*
V 149 240  
W 169 270  
Y 186 300  
(Y) Above 186 Above 300  


Speed ratings apply only to the tire, not to the vehicle. Putting a speed rated tire on any car does not mean the car can be operated at the tire's rated speed.

Speed Symbols
* This refers to tires that have a maximum speed capability above 240 KM/H (149 MPH). "Z" may appear in the size designation. Tires that have a maximum speed capability above 300 KM/H (186 MPH) must have a "Z" appear in the size designation. Consult the tire manufacturer for maximum speed when there is no Service Description.

Winter Tires and Speed Ratings
To maintain tire speed capacity indicated on the vehicle placard, winter tires with the same or higher speed rating should be used. If you decide to use winter tires with speed ratings below what is shown on the vehicle placard, the maximum vehicle operating speed must be reduced to the lowest tire speed rating of the tire mounted on the vehicle. In all cases, Shinco recommends operating speeds not in excess of legal posted speed limits and that speed be reduced appropriately based on weather and road conditions. Winter tire speed ratings do not indicate safe vehicle operating speeds for winter road conditions, including snow, ice, water etc., and drivers must modify vehicular speeds based upon adverse climate changes and conditions.



Ply Rating vs. Load Range
Ply ratings and load ranges identify load and inflation limits of a given tire size when used in a specific type of service.

Conservative driving at the speed limit may improve MPG by 5% in the city and 33% on the highway.
A reduction of 100 pounds of weight in your trunk, (such as tools or sporting equipment) can lead to 1 to 2% better MPG.

Vehicle maintenance:

Uniform Tire Quality Grade (UTQG) Labeling
Required by the government, the UTQG provides comparative manufacturer information. Tires are subjected to a series of government-mandated tests that measure performance in treadwear, traction and temperature resistance. All testing is done by the tire manufacturer.


Treadwear is a measurement of tread durability. Tested against an industry standard, the assigned numerical grade indicates how well the tread lasts compared with a reference standard of 100. A treadwear rating of 200 means the tread wears twice as well as the standard. Actual wear depends on the conditions under which the tire is used. Driving habits, service practices, differences in road surface and varying climates all affect treadwear.


Traction is a measurement of a tire's ability to stop on wet test surfaces of asphalt and concrete under controlled conditions. Traction grades are assigned by the UTQG system and branded on the sidewall. Traction grade is determined only for straight-ahead, wet braking on concrete and asphalt. It doesn't include cornering, which may also be an important customer performance need.

Traction Grade A: The tire performed well on both surfaces.
Traction Grade B: The tire performed well on at least one of the surfaces.
Traction Grade C: The tire performed poorly on one or both of the surfaces.


Temperature Resistance
The UTQG also provides a measure of resistance to heat generation under normal operating conditions. The test is conducted under predetermined standards for inflation and loading. Excessive speed, underinflation and overloading can all cause adverse heat build-up. Sustained high temperatures can reduce tire durability. Resistance grades are branded on the sidewall.

Resistance Grade A: The maximum performance level indicating the tire withstood a half-hour run at 115 mph without failing.
Resistance Grade B: The tire passed 100 mph but not 115 mph.
Resistance Grade C: The minimum performance level indicating that the tire failed to complete a half-hour at 100 mph.


Department of Transportation (DOT) Certification
"DOT" is branded on the tire's sidewall indicating the tire is certified by the Department of Transportation. Following the DOT branding is a serial number designating the tire manufacturer, manufacturing plant, tire size and date of manufacture. Federal law requires that tire dealers record the DOT identification numbers along with the tire buyer's name and address.


Additional Tire Labeling Conventions
Mud and Snow Labeling

If a tire is rated for safe performance in mud and snow, it will be noted on the sidewall of the tire with either M/S, M+S or M&S. A tire is certified under the definitions set forth by the Rubber Manufacturers Association (RMA).

Tire Construction Labeling

Tread ply and sidewall ply information, including tire ply composition and materials used, must also be identified. An example would be: Tread: 2 Plies Rayon + 4 Plies Fiberglass Sidewall: 2 Plies Rayon


Aramid: A synthetic fiber that is, per weight, stronger than steel. Used in tire construction and provides excellent high tensile strength to weight.

Aspect Ratio: An expression representing the height of the sidewall of a tire in terms of a percentage of tire's width.

Asymmetric: When opposite sides of a tire's tread pattern are not identical.

Block Design: A tire tread pattern made of raised rubber- compound segments.

Blocks: The individual, raised rubber-compound segments making up the tread of a tire.

Carcass: That portion of a tire that is the foundation for the tread, belts, bead and sidewall.

Casing: The structure of tire cords locked around wire beads.

Chafer: A finishing strip of calendered fabric used to protect the tire's bead area from the rim.

Compound: The general term referring to the chemical formula for the tread material.

Drive Wheel(s): The wheel(s) that provide the power or driving force for a vehicle.

Filler: The material used to fill the area above the bead between the outer and inner portion of the sidewall. Also used in enlarged form to stiffen the lower sidewall of a tire.

Grooves: Circumferential channels between the tread ribs of a tire.

H-Speed or H-Performance Rated: A speed category for tires with a maximum speed capability of 130 MPH.

High Performance Tire: 1. In the tire industry, those tires with speed ratings of S or greater and aspect ratios of 70 or less. 2. At Shinco, those tires with an aspect ratio of 70 or less and a speed rating of H, V or Z.

Hydroplaning: Loss of traction at high speeds caused by a wedge of water that lifts a tire off the road surface.

Light Truck Tires: Tires designed for off-the-road and on/off-the-road use on sport/utility, small commercial and recreational vehicles.

Load Range: A method of rating a tire's load-carrying capacity (denoted by letters such as B, C, D, etc.) with respect to its ply rating.

Low-Profile: A term describing a tire with a low relative aspect ratio or series classification.

Metric Tire Size System: A tire sizing system using the section width (mm), aspect ratio, speed category, tire construction and the rim diameter (inches). Example: 185/70SR13.

P-metric System: A tire sizing system using the section width (mm), aspect ratio, type of tire construction and rim diameter (inches). Example: P225/70R15.

Passenger Car Tire: Automobile tires featuring aspect ratios of 70 or greater, using a taller profile for increased ride comfort.

Ply: A layer of rubber-coated fabric or wire making up the tire casing.

Radial Tire: A tire built with casing plies that cross the crown at an angle of 90 degrees.

Ribs: Parts of a tire tread pattern created by grooves that run circumferentially around the tire.

S-speed or S-performance rated: A speed category for tires with a maximum speed capability of 112 MPH.

Series: A numerical representation of a tire's aspect ratio; for example, 50 series.

Shoulder Blocks: Raised rubber-compound segments on the part of the tire tread nearest the sidewall.

Sipes: Slits in the tire tread. Small cuts in the surface of the tread to improve traction.

Steel Belt: A belt material used in radial tires. Its high stiffness provides good handling and low treadwear.

Steer Wheel(s): The wheel(s) that direct the course of a vehicle.

Stud Holes: Small cavities along a tire's tread designed to hold tire studs for increased traction on snow-covered surfaces.

Tire Profile: A term representing the portion of a tire measured as its aspect ratio or series.

Touring Performance Tire: A tire providing the ride comfort of a passenger car tire, yet possessing high performance tire characteristics.

Trailer Wheel(s): The wheel(s) of a trailer unit that neither provide power nor direct the course of a vehicle.

Tread Blocks: Raised rubber-compound segments on the outside visible part of a tire.

UTQG: Uniform Tire Quality Grade. A government-mandated tire rating system based on a tire's performance in treadwear durability, traction and temperature resistance. UTQG ratings are branded on a tire's sidewall.

V-Speed or V-Performance Rated: A speed category for tires with a maximum speed capability of 149 MPH.

Varied-Pitch Ratio: Variations in angles and sizes of a tire's tread elements that reduce ride noise levels.

Z-Speed or Z-Performance Rated: A speed category for tires with a maximum speed capability of 149+ MPH.








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