Tire Shopping: Understanding Your Options

Tire Code Part 3: Load Index, Speed Rating, and M+S Designation

When shopping for tires, you can learn a lot about a particular tire by looking at the uniform tire code imprinted on the tire. This code not only identifies the tire, it also provides useful information about the tire. Previously we looked at type of tire and section width, next we discussed at aspect ratio, tire construction and wheel diameter. With this post, we complete our series with a look at last three parts of the uniform tire code: load index, speed rating, and M + S designation.

Performance Index
The tire performance index is displayed after the wheel diameter, and represents the tire’s load and speed ratings.

Common Speed Ratings

Letter L M N P Q R S T U H V
Max. MPH 75 81 87 93 99 106 112 118 124 130 149

All-Season Tires with Mud and Snow Designation
When a tire has M+S on it, that means that it meets the Rubber Manufacturers Association (RMA) guidelines for a mud and snow tire. Similar markings for this include MS, M&S, and M/S. In order for a tire to receive the Mud and Snow designation, it must meet specific RMA geometric requirements.

A tire with the correct tire load index for your vehicle means you that your tires are made to handle the weight of your vehicle. The speed rating shows the maximum speed your tires can handle, which tends to be more important in countries with roadways that are not subject to speed limitations. Whether or not the mud and snow designation is important will depend on the climate in which you live and drive.

Once you’ve purchased your new tires, it is important to follow your vehicle manufacturer’s recommended specifications to assure safety and best vehicle performance. Selecting a dependable, quality tire is just the beginning. Maintaining the proper tire pressure will help you extend the life of your tires .

Tire Shopping: Understanding Your Options

 

Tire ShoppingTire Code Part 2:  Aspect Ratio, Tire Construction, and Wheel Diameter

It is important to familiarize yourself with the differences between the many available tire types when shopping for new tires. In this three-part series, we are looking at the tire code that is imprinted on all tires. Each part of the tire code alpha-numeric sequence identifies something about the tire. Being able to interpret that code can help you choose the best tires for you.

Aspect Ratio

The aspect ratio of a tire is calculated by dividing a tire’s section height by its section width when the tire is:

  • inflated to proper air pressure
  • mounted on the approved measuring rim
  • under no load

The aspect ratio affects steering stability. Generally, the shorter the sidewall, or the lower the aspect ratio, the less time it takes to relay the steering input from the wheel to the tire, for faster steering response. Aspect ratio also affects the tread contact patch. A low-profile tire typically produces a wider tread contact patch. This wider tread contact patch creates a firmer footprint that provides improved cornering traction.

Tire Construction

The construction of the tire is identified by the letter following the aspect ratio. The most common designation is R, which stands for radial construction. Other, less common construction types for modern passenger cars may include D for bias ply construction and B for belted tires.

Wheel Diameter

The number following the construction code indicates the size of the wheel that the tire will fit in inches. Tire sizes on most vehicles begin at 13-inches and go up to 18-inches. Custom package wheels can be 22-inches or even larger.

An important sizing calculation in tire fitting, aspect ratio should be considered with wheel diameter for the best tire and wheel combinations. Lower aspect ratio typically indicates a high performance tire, with better lateral stability. Most of the new tires will be marked R for radial construction, however if you are replacing old tires, you may see the D or B designations.

When considering aspect ratio, tire construction, and wheel diameter, you should always select your vehicle manufacturer’s recommended specifications to assure safe and optimal tire performance. Just as choosing a dependable, quality tire is important, it also necessary to choose one that is developed for the best performance given the weight and design of your vehicle.

Next Up: Tire Code Part 3:  Load Index, Speed Rating, and Use Designation.

Tire Shopping: Understanding Your Options

Tire Shopping: Understanding Your OptionsShopping for tires can be a little overwhelming with the wide range of styles and choices that are available. It is important to choose the right tire for your vehicle and the type of driving you do in order to get the best safety, performance, and gas mileage from your vehicle. So, how do you go about choosing the right tires?

Getting to know the differences between the many tire types that are out there is a great place to start. In this three-part series, we will look at the tire code that is imprinted on all tires. Each part of the tire code alpha-numeric sequence tells you something about the tire. Understanding that code can help you find the right tires.

Tire Code Part One: Tire Type and Section Width

Type of Tire

The type of tire and it’s intended use are indicated by the first letter in the code. Letter designations include P for passenger vehicles, T for temporary spare, LT for light truck metric, C for commercial, and ST for special trailer service.

Section Width

Following the tire type letter is the section width of the tire, which is listed in millimeters. This is the widest point from sidewall-to-sidewall, so a larger number indicates a wider tire.

The proper size and tire type are important to assure safety and the best tire performance. Buying a quality tire will not guarantee the best performance if the tire is not made to accommodate the weight and design of your vehicle. Also, since tire size is a factor in the calculations of the computerized functions of today’s vehicles, it is essential to install the recommended tire size.

Next Up: Tire Code Part 2:  Aspect Ratio, Tire Construction, and Wheel Diameter

Tire Pressure: Seeing the Light on a Cold Truth

Tire Pressure Cold TemperatureDoes it seems like you have been seeing your tire pressure monitoring system light illuminating a little more frequently lately? If so, you can probably blame one simple reason – the cold.

In order to understand how cold effects your TPMS, it is necessary to how your TPMS works. The system use sensors technology to alert drivers when tire pressure in one of the tires goes below a predetermined level. When tire pressure in one or more of your tires drops, the light comes on.

Since ambient air pressure decreases in frigid temperatures, the air pressure in a tire goes down 1-2 pounds for every 10 degrees of temperature change. This is why drivers typically see the TPMS light illuminate more frequently.

It is important to check your tire pressure when the tires are cold. Why? Once you hit the road, friction will cause the tires to heat up, increasing the pressure within the tire. Checking the tire pressure after you have been driving awhile may give an inaccurately high pressure reading.

Proper tire inflation is always important, but it is especially critical in the cold winter months when weather conditions make driving more hazardous. Tire pressure is important because:

  • Low tire pressure can make a vehicle handle poorly
  • Tires tend to wear out much faster when they are not properly inflated
  • Under inflated tires tend to overheat, which could lead to a blowout
  • Low tire pressure reduces gas mileage and costs you money

Check the pressure of your tires monthly. In order to obtain the most accurate pressure level, wait until tires have cooled – about 30 minutes after parking – or check the pressure first thing in the morning.

 

Driving on Old Tires is Scary!

driving_on_old_tires

Today is a day for tricks, treats, and fun, but it also seems like a good day to remind drivers of something truly scary – driving on old tires! Not only is it critical to recognize the signs of worn out, dangerous tread, it is also important to understand that even if old tires look okay, they could be seriously compromised and a safe driving hazard.

Old tires often show no visible sign of deterioration. While they may appear to be safe, usable tires, cracks can develop both on the inside and the outside of the tire. Since the rubber compounds used in tires degrade over time, cracks will develop in the rubber, regardless of mileage and wear. Ultimately, this cracking leads to the steel belts in the tread separating from the rest of the tire.

The Rubber Manufacturers Association reports that putting an expiration date on a tire can be difficult since factors such as heat, driving, and storage conditions can greatly impact the usable life of a tire. The recommendation of the National Highway Traffic Safety Administration (NHTSA) is to refer to the guidelines set by the specific tire manufacturer when it comes to tire aging and usable life.

In some cases, such as a used car purchase, the origin and age of a tire might be unknown. You can still find out how old those tires are. In 2000 the U.S. Department of Transportation began requiring tires to have a DOT code. With this code, you can learn details about the tire, including its age. Decipher the code by downloading a free app offered by the Tire Safety Group. Available for Android and iPhone, the app enables you to get to get a free Tire Facts Report by simply entering the DOT code from your tire.  The report lets you know if a tire is old, defective, or has been the subject of a recall. The app shows you where to find the code on the tire and even includes a flashlight function to help you see the code clearly!

If you find out your tires are too old to drive on, go out and buy some new tires as soon as possible! As for your old tires, look for a creative way to recycle them:

recycle old tires

Image Courtesy of Pinterest

Happy Halloween and Safe Travels!

Tire Types Explained

tire-typesThere are many factors to consider when it comes to selecting tires. While it is important to choose a quality brand and get a good value, it is equally essential that you buy the right type of tires for your vehicle. The tire type you select should be not only be recommended for your vehicle, but also suited  for the kind of driving you do. A wide range of tire types are available to suit every kind of vehicle and all driving conditions.

Below is a listing of the most common tire types, as well as the corresponding speed rating. The speed rating and tire type are both identified in the tire code, found imprinted on the side of all tires.

All Season Tires

The most common speed ratings for all season tires are S and T. All season tires deliver a good all-weather grip and long mileage. They are most commonly used  standard cars and SUVs.  All season tires are designed to perform in a wide range of conditions from dry pavement to wet weather and light snow. A good choice for a comfortable and quiet ride, all season tires offer reliable handling and long tread life. For year-round traction in moderate climates, all season tires are an excellent choice.

Performance All Season Tires

Performance all season tires have H and V speed rating and are a popular choice for cars with enthusiast appeal or upgraded wheels. These tires feature a better cornering grip than regular all-season tires, but typically need to be replaced more often.

 

Winter/ Snow Tires

Winter or snow tires are identifiable by a mountain and snowflake symbol displayed on the sidewall. Winter tire tread is designed with gripping edges for better handling on snow and ice. They are made with a softer rubber compound to stay flexible in extremely cold temperatures. Winter tires do not perform as well on cleared roads, lacking the solid grip of all season tires. They also tend to wear more quickly. Winter tires should be exclusively used during extreme cold weather driving conditions.

Summer Tires

Summer tires usually have speed ratings of ZR, W, and Y,  for sports cars and performance sedans. For all-around best performing tires in mild climates and seasons, summer tires offer a performance level above all season tires. As the name implies,  summer tires are not suited for driving in snow and ice, but they offer solid handling on dry and wet roads in mild temperatures. Summer tires are also made with softer compounds however, unlike those used in winter tires, they become harder in colder temperatures. Though they tend to have shorter life span and more rapid tread wear, summer tire do offer enhanced driving performance.

All  Terrain Truck Tires

All terrain truck tires are available in larger sizes and designed for light duty hauling and towing. They are a great choice for light-duty pickups and SUVs. All-terrain tires usually have a more aggressive tread pattern to aid off-road traction. All-terrain tires usually have A/T or All Terrain in the model name.

 

Understanding Tire Code: Load Index, Speed Rating, and M+S Designation

The uniform tire code is imprinted on nearly every vehicle tire manufactured. This code not only identifies the tire, it also provides useful information about the tire. The first post focused on the type of tire and section width and the second post looked at aspect ratio, tire construction and wheel diameter. With this post, we complete our look at tire code with an explanation of the last three parts of the uniform tire code: load index, speed rating, and M + S designation.

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Tire Code – Performance Index, Speed Rating, and Mud and Snow Designation

Performance Index
The tire performance index is displayed after the wheel diameter, and represents the tire’s load and speed ratings. In this case, the 93 load index represents 1,433 pounds, and the speed rating of V represents 149 mph.

Common Speed Ratings

Letter

L

M

N

P

Q

R

S

T

U

H

V

Max. MPH

75

81

87

93

99

106

112

118

124

130

149

All-Season Tires with Mud and Snow Designation
When a tire has M+S on it, that means that it meets the Rubber Manufacturers Association (RMA) guidelines for a mud and snow tire. Similar markings for this include MS, M&S, and M/S. In order for a tire to receive the Mud and Snow designation, it must meet specific RMA geometric requirements.

A tire with the correct tire load index for your vehicle means you that your tires are made to handle the weight of your vehicle. The speed rating shows the maximum speed your tires can handle, which tends to be more important in countries with roadways that are not subject to speed limitations. Whether or not the mud and snow designation is important will depend on the climate in which you live and drive.

Along with looking at the tire code, it is important to follow your vehicle manufacturer’s recommended specifications to assure safety and best vehicle performance. Selecting a dependable, quality tire is just the beginning. Maintaining the proper tire pressure will help you extend the life of your tires .

Understanding Tire Code: Aspect Ratio, Tire Construction, and Wheel Diameter

Understanding Tire CodeThis is post number two in our series on understanding tire code. The universal tire code is found on every vehicle tire manufactured, and provides information about the type of tire it is, what type of vehicle it is designed for, and the type of driving it is intended to do.

In our last post, we talked about tire and section width. Today, we will look a little further into the code, and take a look at aspect ratio, tire construction, and wheel diameter.

Aspect Ratio

Tire Code

Tire Code

The aspect ratio of the tire is listed as a percentage and gives the height of the tire from the bead to the top of the tread. Here the number is 55, which means the tire height is 55% of the section width of 215 millimeters. The height of this tire would be 118.25 millimeters. A lower number indicates a lower tire profile.

Tire Construction

The construction of the tire is identified by the letter following the aspect ratio. The most common designation is R, which stands for radial construction. Other, less common construction types for modern passenger cars may include D for bias ply construction and B for belted tires.

Wheel Diameter

The number following the construction code indicates the size of the wheel that the tire will fit in inches. The example tire would be designed to fit a 17-inch wheel. Tire sizes on most vehicles begin at 13-inches and go up to 18-inches. Custom package wheels can be 22-inches or even larger.

An important sizing calculation in tire fitting, aspect ratio should be considered with wheel diameter for the best tire and wheel combinations. Lower aspect ratio typically indicates a high performance tire, with better lateral stability. Most of the new tires will be marked R for radial construction, however if you are replacing old tires, you may see the D or B designations.

When considering aspect ratio, tire construction, and wheel diameter, you should always select your vehicle manufacturer’s recommended specifications to assure safe and optimal tire performance. Just as choosing a dependable, quality tire is important, it also necessary to choose one that is developed for the best performance given the weight and design of your vehicle.

Next time, we will look at the remaining portion of the tire code, which includes Load Index, Speed Rating, and Use Designation.

Understanding Tire Code: Tire and Section Width

Understanding Tire CodeAnyone who has shopped for tires understands that the wide array of choices can leave you feeling overwhelmed and  wondering how you will ever figure out which tires are the right choice for your vehicle.

While some may go into the tire buying experience thinking all tires are basically the same, they soon discover there are actually many distinct characteristics and features to consider when selecting tires.It may seem impossible to tell one tire from the next at a glance, but if you look more closely, each tire tells you a lot through its tire code.  Imprinted into the side of the tire, you may have noticed the tire code on your tires from time to time, while washing your car or checking your tire pressure.

Each part of the tire code alpha-numeric sequence tells you something about the tire. Being able to read the tire code on your current tires will help you determine the type of replacements you need.

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Type of Tire and Section Width

Type of Tire

The type of tire and it’s intended use are indicated by the first letter in the code. Letter designations include P for passenger vehicles, T for temporary spare, LT for light truck metric, C for commercial, and ST for special trailer service. 

Section Width

Following the tire type letter is the section width of the tire, which is listed in millimeters. This is the widest point from sidewall-to-sidewall, so a larger number indicates a wider tire. In this case, the tire has a width of 215 millimeters.

The proper size and tire type are important to assure safety and the best tire performance. Buying a quality tire will not guarantee the best performance if the tire is not made to accommodate the weight and design of your vehicle. Also, since tire size is a factor in the calculations of the computerized functions of today’s vehicles, it is essential to install the recommended tire size.

Next time, we will continue looking at tire code with understanding the Aspect Ratio, Tire Construction, and Wheel Diameter.

Old Tires Can Be Dangerous

old tiresMost everyone understands that driving on compromised tires is dangerous. It is important to inspect tires and measure tread depth on a regular basis to assure that tires are safe. There is another tire problem, though, that many drivers may not even realize is a safety issue. Old tires can be dangerous, even if the tread appears to be okay.

In many cases, old tires show no visible sign of deterioration and appear to be safe, usable tires. Because they are rubber products, tires have a limited service life, since tire rubber compounds deteriorate over time. Regardless of wear and mileage, cracks develop in the rubber as they age. These cracks can occur on both on the inside and outside of the tire. Eventually this cracking leads to the separation of the steel belts in the tread from the rest of the tire.

According to the Rubber Manufacturers Association, it is not easy to put a specific expiration date on a tire since factors such as heat, driving, and storage conditions can greatly impact a tire’s usable life. The National Highway Traffic Safety Administration (NHTSA) recommends following the guidelines established by the specific tire manufacturer when it comes to tire aging. 

In situations where the origin and age of a tire are in question, you can learn something from the tire itself. Since 2000, tires are required by the U.S. Department of Transportation to have a DOT code. This code provides details about the tire, including its age. The code can be deciphered by downloading a free app offered by the Tire Safety Group. The app, available for Android and iPhone, enables you to get to get a free Tire Facts Report by entering the DOT code from your tire.  The report lets you know if a tire is old, defective, or has been recalled. The app shows you where the code is located on the tire and even includes a flashlight function so you can see what you are doing!

Remember – never take any chances with your tires. Too much is riding on them!