Section 1- How To Read A Sidewall/ Tire Types Flashcards
How to Read a Sidewall P205/65R15- what's this mean? P: passenger(p-metric)/LT-light truck 205: Width of the tire in millimeters 65: Aspect ratio (tire height as % of width) R: Radial design 15: Wheel diameter in inches 92: Load rating S: Speed rating (performance rating)
Let’s move away from tire anatomy and begin to look at sizing and the important information displayed on the sidewall. Here’s a tire size designation. Some of this is likely a review so take it apart and see how we do.
How to Read a Sidewall
- load rating is the maximum load at rated speed and inflation
- always replace tires with the same or greater load rating
- specified by the OEM vehicle engineers
Load index table
Let’s take a look at load ratings. This 2 or 3 digit number indicates the maximum weight that a tire can safely accommodate. The sizing example we used a few minutes ago showed the tire was a 92S. Using the chart find the 92 designation and follow the table across to convert it to pounds. How many pounds can that tire safely handle? (1389) Multiply that times four tires and you get the carrying capacity for the set. This is the maximum amount of the vehicle weight, passenger weight, and load that can be accommodated by the tires. This is why it is essential when replacing tires to meet or exceed the factory specifications for load rating. Not doing so could compromise safety when carrying large passenger or cargo loads.
How to Read a Sidewall
- Speed rating is the maximum speed at rated load and inflation
- Speed rating should be referred to as a “performance rating”
- Always replace with the same or higher speed rating
- Specified by the OEM vehicle engineers
Now let’s look at speed ratings. Speed ratings were developed in Europe where there are no speed limits on some roads. The authorities wanted to be sure tires could safely handle high speeds. So instead of limiting the speed of the road, the speed of the tire was designated. Speed ratings should be referred to with the customer as”performance ratings”, in that it designates the acceleration, breaking, cornering and heat dissipate abilities of a given tire. Typically, within the passenger vehicle market we will see tires with speed ratings from S-ZR. To use the table find the speed designation and follow it across to the maximum sustained speed the tire is rated for. When replacing tires it’s important to meet or exceed the factory specification for speed ratings just like you would with load ratings in order to maintain the same ride quality and safety.n
How to Read a Sidewall
Tire Ply Composition indicates the number of layers of rubber-coated fabric and the materials in the tire including steel, nylon, polyester and others.
When looking at the bottom of page 3 in your workbook you will see reference to some other key terms and definitions.
The tire ply composition indicates the number of layers of rubber-coated fabric and the materials in the tire including steel, nylon, polyester, and others.
How to Read a Sidewall
Maximum tire pressure indicates the greatest amount of air pressure that should ever be put into the tire. The proper amount of air pressure to actually put into the tire is found on the vehicle tire information label on the drivers door.
Maximum tire pressure indicates the greatest amount of air pressure that should ever be put into the tire under maximum load. The proper amount of air pressure to actually put into the tire is found on the vehicle tire information label on the drivers door or owners manual.
How to Read a Sidewall
Maximum load rating indicates the load in kilograms and pounds that can be carried by the tire.
Finally, Maximum load rating indicates the load in kilograms and pounds that can be carried by the tire. This is the equivalent to using the load rating table to convert the size designation.
How to read a sidewall: DOT number
The DOT (date of transportation) tire identification number is a 10 (or 11) digit ID required by the federal government.
DOT: compliance with the U.S. department of transportation
MA: manufacturer & plant code
L9: Tire size code
ABCD: Tire type code
0913: Production code- the date of manufacture- 9th week of 2013
Also on the sidewall is the DOT number. The DOT is not a unique serial number. Many tires can have the same DOT number. The DOT number identifies a number of things, but the one that’s important to us is the 4 digit production code. The production code indicates the week and year of manufacture. So “0913” would be the 9th week of 2013.
Why would the DOT number be important to dealership service departments? (Allows associates to determine the age of the tire. This is how safety recalls are tracked)
Since the DOT number is how customers are informed of any tire recalls, it is a federal mandate that anyone selling tires gives the customer a chance to register their tires via DOT registration card or does so as a courtesy to the customers through the program website. Dealerships who use our system can rest assured that Dealer Tire will contact any customers affected by these recalls and route the, back to the dealer for service.
How to read a sidewall: UTQG System
Tread wear rating- design life of the tire, usually between 100-800
Traction rating- Anility to brake on straight test track
Temperature rating- Ability to dissipate heat
Another useful designation is the UTQG system. The UTQG syste, was developed by the federal government in an effort to help customers compare tires. There are three ratings on each tire; tread wear, traction and temperature. Tread wear measures the design life of the tire. In general the larger the number the longer the life will be. This assumes that a 400 tire is supposed to last twice as long as a 200 tire. The traction rating is the tires ability to grip the road braking on a wet test track. The temperature rating is the tires ability to dissipate heat. This is an important rating, in that the heat is the number one cause of tire failure. Heat is generated by the constant flexing of the tire casing, especially the sidewalls. Most all high performance tires have an “A” temperature rating.
There is a very important caution in using these ratings. It is really only useful when comparing tires from the same manufacturer. If the UTQG is used, it should be used when comparing a Goodyear to a Goodyear or a Michelin to a Michelin, etc.
Two different tires from dealerships inventory- graph the UTQG ratings using table in workbook. If actual tires aren’t available use DRSG compare tool- longevity and performance conclusions
Tires with higher tread wear ratings will sacrifice traction in many circumstances due to the hard rubber compounds, while tires rated high for traction will have lower tread wear score due to the soft compounds used.
Tire Types
Passenger
Touring
Performance
Finally we will round out this section by reviewing the different types of tires you will come across at the dealership while documenting the pros and cons of each variety in your workbook.
Tire types
P-metric light truck
- built to suit SUB and truck owners
- similar in load capacity to passenger tires
- deeper more aggressive tread
- nylon wrapped for greater stability and damage resistance
A few other tire varieties that are common,t sold and serviced in dealerships include P-metric light truck tires. These are similar to passenger tires, but with deeper tread and a more aggressive look that suits SUV and truck owners. P-metric tires are what the majority of SUV and truck owners should drive, since their vehicles are used much like cars.
Tire types
Light truck
- “LT” on sidewall
- reinforced sidewalls for greater loaf carrying capacity.
- more aggressive tread design for improved traction in foul weather conditions
- designed for construction, hauling, and off-road use
Another variety is the light truck tire. Light truck tires have “LT” designation on sidewall. LT tires have reinforced sidewalls for greater load carrying capacity and a more aggressive tread design for improved traction in foul weather conditions. These tires pare designed to be used in off-reading, construction, and hauling heavy payloads.
Tire types
Run flats
- supports the vehicle after the loss of pressure
- sidewall reinforced run-flat tire use strong rubber, wider beads and special bead filler
- available in passenger, touring, performance, P-metric light truck and light truck tires
Run-flat designs are available in passenger, touring, performance, P-metric light truck and light truck tires.
Sidewall-reinforced run-flats, which are the only current form of construction, use strong rubber, wider beads and a special bead filler to support the vehicle after a loss of pressure.
Tire types
Winter tires
- recommended for use when the temperature is below 45 degrees F
- softer rubber compounds remain flexibility to provide better grip and vehicle control.
- special tread sipes add lateral traction
-unique winter tire designation
Finally winter tires are recommended for use when temperatures regularly fall below 45 degrees F. They feature softer rubber compounds that remain flexible at extreme temperatures allowing them to conform better to the road for improved grip and vehicle control. Winter tires are also covered in sipes for additional lateral traction. Genuine winter tires carry a unique designation on the side wall- a snowflake inside a mountain.
