Multiquip SG1400C3 operation manual Tire FundamenTalS, Letter rating Speed rating

trailer guidelines

Use the information contained in this section to make tire safety a regular part of your vehicle maintenance routine. Recognize that the time you spend is minimal compared with the inconvenience and safety consequences of a fl at tire or other tire failure.

Tire FundamenTalS

Federal law requires tire manufacturers to place standardized information on the sidewall of all tires (Figure J). This information identifies and describes the fundamental characteristics of the tire and also provides a tire identifi cation number for safety standard certifi cation and in case of a recall.

Figure J. Standard Tire Sidewall Information

p: The “P” indicates the tire is for passenger vehicles.

next number: This three-digit number gives the width in millimeters of the tire from sidewall edge to sidewall edge. In general, the larger the number, the wider the tire.

next number: This two-digit number, known as the aspect ratio, gives the tire’s ratio of height to width. Numbers of 70 or lower indicate a short sidewall for improved steering response and better overall handling on dry pavement.

p: The “R” stands for radial. Radial ply construction of tires has been the industry standard for the past 20 years.

next number: This two-digit number is the wheel or rim diameter in inches. If you change your wheel size, you will have to purchase new tires to match the new wheel diameter.

next number: This two- or three-digit number is the tire’s load index. It is a measurement of how much weight each tire can support. You may fi nd this information in your owner’s manual. If not, contact a local tire dealer. Note: You may not fi nd this information on all tires because it is not required by law.

m+S: The “M+S” or “M/S” indicates that the tire has some mud and snow capability. Most radial tires have these markings; hence, they have some mud and snow capability.

Speed rating: The speed rating denotes the speed at which a tire is designed to be driven for extended periods of time. The ratings range from 99 miles per hour (mph) to 186 mph.These ratings are listed in Table A. Note:You may not fi nd this information on all tires because it is not required by law.

Table a. Speed rating

letter rating	Speed rating
Q	99 mph
R	106 mph
S	112 mph
T	118 mph
U	124 mph
H	130 mph
V	149 mph
W	168* mph
Y	186* mph

u.S. doTTire identification number:This begins with the letters “DOT” and indicates that the tire meets all federal standards. The next two numbers or letters are the plant code where it was manufactured, and the last four numbers represent the week and year the tire was built. For example, the numbers 3197 means the 31st week of 1997.The other numbers are marketing codes used at the manufacturer’s discretion. This information is used to contact consumers if a tire defect requires a recall.

Tire ply Composition and materials used:The number of plies indicates the number of layers of rubber-coated fabric in the tire. In general, the greater the number of plies, the more weight a tire can support. Tire manufacturers also must indicate the materials in the tire, which include steel, nylon, polyester, and others.

maximum load rating: This number indicates the maximum load in kilograms and pounds that can be carried by the tire.

maximum permissible inflation pressure: This number is the greatest amount of air pressure that should ever be put in the tire under normal driving conditions.

page 58 — SG1400C3 Studio Generator • operation manual — rev. #0 (10/05/11)