You’re walking through a parking lot or maybe giving your car a quick wash, and you notice a series of letters and numbers molded into the side of your tires. Among them, you’ll almost certainly see “M+S” or “M&S.” It’s one of the most common markings, yet its meaning is often misunderstood. Knowing what these symbols represent is more than just trivia; it’s a key piece of information for your safety and your vehicle’s performance in various driving conditions.
This guide is designed to help you decipher the code written on your tires. We’ll answer the central question, What Does M + S Mean On Tires: A Guide To Tire Markings, and then go beyond it to explore other important symbols you should know. By the end, you’ll be able to look at your tires and understand exactly what they’re built for, helping you make more informed decisions for your next set.
What Does M + S Mean On Tires: A Guide To Tire Markings
Let’s get straight to the point. “M+S” stands for “Mud and Snow.” This marking indicates that the tire has been designed with certain features that make it more capable in loose, soft terrain like mud and in snowy conditions compared to a standard highway tire. You’ll typically find M+S markings on a wide range of tires, including all-season tires and many light truck tires.
It’s crucial to understand what M+S doesn’t mean. The M+S designation is a self-certified standard, meaning the tire manufacturer decides if their tire meets the criteria. While these tires do have more aggressive tread patterns with deeper grooves and biting edges than summer tires, they are not specifically tested to a government performance standard for severe snow conditions. This is the most common source of confusion for drivers.
The Critical Difference: M+S vs. The Three-Peak Mountain Snowflake
This is where a second symbol becomes incredibly important. If you see a tire with an M+S marking and a symbol of a three-peak mountain with a snowflake inside it, you have a true winter tire. This symbol is known as the Three-Peak Mountain Snowflake (3PMSF).
Unlike the M+S marking, the 3PMSF symbol is a regulated standard. To earn it, a tire must meet specific performance criteria in accelerated testing on packed snow and ice. A tire with the 3PMSF symbol will provide significantly better traction, braking, and handling in cold weather (typically below 45°F or 7°C) and on snow and ice-covered roads than an M+S-only tire. In many regions with harsh winters, having this symbol is a legal requirement during winter months.
Decoding the Rest of Your Tire’s Sidewall
Your tire’s sidewall is a treasure trove of information. Beyond M+S, here are the other key markings you should be able to read.
The Tire Size and Type: You’ll see a sequence like “P215/65R16 95H.” Here’s a quick breakdown:
P stands for Passenger vehicle (you might see LT for Light Truck).
215 is the tire’s section width in millimeters.
65 is the aspect ratio, the height of the sidewall as a percentage of the width.
R means Radial construction.
16 is the wheel diameter in inches.
95 is the load index, a code for the maximum weight the tire can support.
H is the speed rating, indicating the maximum speed the tire can sustain.
DOT Tire Identification Number: This code starts with “DOT” and ends with a four-digit number. The last four digits are the most important for you—they are the week and year the tire was manufactured. For example, “3522” means the tire was made in the 35th week of 2022.
Treadwear, Traction, and Temperature Grades: These are part of the Uniform Tire Quality Grading (UTQG) system. Treadwear is a comparative wear rating, Traction indicates wet braking capability, and Temperature grades the tire’s ability to dissipate heat. Higher numbers or letters are better.
Why Understanding These Markings Matters for You
Knowing how to read your tire markings empowers you as a vehicle owner. It allows you to select the right tire for your local climate and driving habits. If you live in an area with mild winters where it rarely snows, an all-season tire with an M+S rating may be perfectly adequate. However, if you experience consistent freezing temperatures and snow, investing in a tire with the Three-Peak Mountain Snowflake symbol is a critical safety decision.
It also helps you verify you’re getting the correct tire size and type when replacing your tires, ensuring your vehicle’s speedometer and safety systems like ABS and traction control function as intended. Checking the DOT date can also help you avoid buying old, potentially degraded tires, even if they look new.
Making the Right Choice for Your Drive
When it’s time for new tires, use this knowledge. Don’t assume an M+S marking makes a tire suitable for a harsh winter. Look for the 3PMSF symbol if you need true winter performance. For summer driving, a tire without M+S may offer better dry and wet road handling. Always consult with a trusted tire professional who can help you match the tire’s capabilities, as shown by its markings, to your specific vehicle and driving needs.
In summary, “M+S” means a tire is designed for mud and snow, but it’s not a certified winter tire. The true indicator of winter performance is the Three-Peak Mountain Snowflake symbol. By taking a few moments to understand the M+S marking and the other codes on your tire’s sidewall, you gain valuable insight that contributes directly to your safety, your vehicle’s performance, and your peace of mind on the road.