How to read tire size and type Complete Guide

Are you confused when it comes to understanding the size and type of tire your car needs? Don’t worry, this guide will help you decode all the characters and numbers on your tire so you can make an informed decision on the right replacement.

You’re just a few steps away from being a pro at reading tire size!

When learning how to read tire size, it is important to understand the coding system used to denote what type of tires are on your vehicle. Use this guide as an overview of tire types and sizes, the components of tire size information, how to measure for the right size tires for your car, and the best place to purchase tires. With a better understanding of tire specifications and sizing, you can make an informed decision and purchase suitable replacements or upgrades.

At its basic level a tire size consist of three elements – section width, aspect ratio and wheel diameter expressed in inches as follows:

  • Section Width is expressed in 215/45R17 91H
  • Aspect Ratio expressed in 215/45R17 91H
  • Wheel Diameter expressed in 215/45R17 91H

In addition there will be a Load Index (LI) and Tire Speed Rating (TSR) code that must be considered when selecting the right tire:

  • Load Index LI – This is a two or three-digit (91) rating indicating maximum permissible load for any given tire (see Load Index Table). Do not exceed manufacturer’s specified inflation pressure as indicated on tire sidewall as it could lead to serious structural damage with potential injury or death.
  • Tire Speed Rating TSR – can range from J up to Y (50 mph up 149 mph). Consult your vehicle’s handbook for the recommended TSR speed code for use on your vehicle.

Understanding tire size

Reading tire size and type is a critical part of selecting the best wheel for your car. Different wheel sizes have different load capacities and may have different speed ratings. Knowing tire size and type can also help you be sure of the correct fitment when buying replacement tires.

There are a few components involved in determining tire size. The most common are:

-Tire Section Width: This is the width of a tire in millimeters, labeled as “205 mm” or “205/35” on the side wall of the tire.

-Wheel Diameter: This is the diameter of your wheel in inches. It can be found on either side wall (ex: 18 inch).

-Aspect Ratio: This is the height of your sidewall in comparison to its width, labeled as “35” in our previous example (205/35). The lower the number,the lower profile look it will give you and vice versa with higher numbers.

-Radial Construction (R): Most tires today consist of radial construction, so your wheels should have an “R” stamped somewhere on them if they are radial tires.(The symbol for steel belted radials – “SR” or “M+S” – also appear here.)

-Load Index Rating: Tire speed rating can also be found on one side (ex: 97H). The load index rating tells you how much weight each tire can support when inflated to its maximum pressure level; higher numbers mean a greater load capacity than lower numbers.

Explanation of tire size markings on the tire sidewall

When shopping for tires, you’ll notice tire sizes have one or more numbers and letters on the sidewall. This information is used by mechanics to identify the right fit and performance characteristics of the tire. Understanding how to read tire size is important when finding new tires and/or conducting routine tire maintenance.

The most common sizes are found on passenger vehicles like cars, crossovers and SUVs, but can also be found on light trucks, minivans, trailers and some small commercial vehicles. While each manufacturer may use slightly different markings that indicate size, the basic principles remain the same.

Tire size will typically appear on one side of a tire in a set format, such as 265/75R16 114S or P265/75R16 114S. The first set of numbers (265) is the section width of a tire in millimeters from sidewall to sidewall; 75 refers to aspect ratio as aspect ratio measures height from wheel rim to top of tread (tread height). R indicates single-ply construction with steel belts reinforced for radial application; 16 denotes wheel diameter that determines which wheels the tire can fit on; lastly, 114S identifies load range index and speed rating respectively from available options provided by the manufacturer. The letter classifying speed rating must match existing tires already mounted before any replacement takes place as it is important reflect vehicle’s top speed capability supported by matching specifications of existing counterpart.

Breakdown of each component of the tire size marking

The tire size designation is made up of a combination of numbers which are used to identify the tire’s width, aspect ratio, construction type, radial size and load index. From there you’ll be able to determine the speed rating and other key characteristics that help make sure your tires are safe for your specific vehicle.

Width: The three-digit number before the slash mark denotes the width of the tire in millimeters from sidewall to sidewall. This is a distance across the section width from edge to edge. The larger this number, the wider your tire will be in relation to its profile.

Aspect Ratio: The two digit number after the slash mark is called the aspect ratio or profile height. This corresponds to how tall your tire’s sidewall will be as a percentage of its section width. So if this example reads ‘50’ that means that your tire has an aspect ratio of 50%. A higher aspect ratio often correlates with increased performance, while a lower ratio equates to tires geared more towards handling and cornering capacity than outright grip levels on track day driving activities or during performance-oriented drifting stunts in controlled conditions on closed circuits.

Radial Designation: Afterward there’s usually an R denoting radial construction – which just means how much malleability or give certain tires have when compressed versus their OEM standard counterparts – followed by a two-digit wheel size designation for both imperial and metric sizing options into one uniform framework so that everyone understands exactly what size wheel has been considered for general maintenance operations such as changing summer tires over for winter ones – what’s commonly called seasonal rotation services by many professional car care specialists available today around marquee pedigreed motorway networks spanning all continents around our world taken as a whole whenever they come together as necessary anytime soon enough with any luck at all until then maybe..

Importance of selecting the correct tire size for your vehicle

Selecting the right tire size and type for your vehicle is an important process. Ensuring proper fitment to your vehicle’s wheel assemblies is critical, as an improper fit can lead to increased wear, decreased ride quality, and inadequate performance. Additionally, incorrect selection of certain tires can compromise the safety features of your car or may not meet certain regulations imposed by governments.

Therefore, it is important that you understand how to read tire size and what type of tire you need based on factors such as speed rating, load ratings, and tread design. This complete guide will provide you with all the information required to select the right kind of tire for your vehicle correctly and safely. The information required includes the tire type (Radial or Bias), tread design (all-season or snow/winter tires), speed rating (kph/mph), load index (how much weight each tire can handle safely) and features such as anti-skid capabilities.

When selecting a new set of tires for a given vehicle it is critical that all these elements are taken into consideration. Furthermore, some vehicles may require special considerations when selecting tires such as a particular hole count from the rim that requires use with a specific size and type of tire. It is also recommended that only specified winter/snow tires are installed if using them in winter conditions – this will ensure that your safety remains uncompromised in case of slippery surfaces or snow covered roads.

How can I tell what size my Tyres are?

III. Understanding tire type

Tires come in a variety of types, designated by their “Load Index” and “Speed Rating”. The Load Index is an assigned numerical value that corresponds to the maximum weight capacity of a tire, while the Speed Rating refers to the maximum speed which the tire can support under certain load conditions. Knowing these codes will help you ensure you purchase the correct tire for your vehicle.

The most common type of tire used today is the P metric (passenger car) size. These tires are most often used on vehicles with four wheels, like cars and SUVs. The P metric tire type is marked with a P preceding a three-digit number on the sidewall (e.g., “P225/55R17”).

In addition to passenger car tires, there are several other types of tires geared toward different types of vehicles and applications: LT (light truck) tires; ST (special trailer) tires; ATV (all-terrain vehicle) tires; and flotation or agricultural machinery tires. Each type comes with its own Load Index and Speed Rating codes. Additionally, some special applications require higher speed ratings than those found on other types of vehicles – these will be noted on the sidewall in an enclosed circle containing a letter code at the end of the number sequence after specifying size information for that same tire order.

Explanation of tire type markings on the tire sidewall

When selecting a tire, it is important to confirm the size and type as found on the tire sidewall. The sidewall contains vital information on the tire’s size, load capacity, maximum pressure, tread life and speed rating.

Here’s a breakdown of some common markings located on a standard tire sidewall:

Tire Size – This number indicates the diameter of your wheel in inches and its width in millimeters (e.g.: 205/55R16).

Load Capacity – This number tells you the maximum carry weight your tires can handle when properly inflated according to manufacturer recommendations (e.g.: 91V).

Maximum Pressure – This number tells you the maximum amount of air pressure that should be pumped into each tire for optimum performance (e.g.: 44 psi).

Tread Life – This number indicates how many miles you can expect to get out of your tires once they’ve been worn down to a certain point (e.g.: 600).

Speed Rating – Speed Rating is an international standard which equals Tire types as A=to this letter stands for a speed rating, Y =186 mph or 300 km/h (e.g.: P = 87 mph or 140 km/h ).

By understanding how to read these numbers, you will be armed with information needed when buying tires or conducting your own automotive maintenance projects.

Breakdown of each component of the tire type marking

Reading tire size and type is an essential skill for all motorists. Fortunately, the required information is conveniently available on the sidewall of your existing tires. Understanding each of the components of this marking can help you determine which replacement tires are best suited for your vehicle’s needs.

The tire type marking typically consists of three components: a letter or letters, followed by a number and finally, a letter or letters.

The first component, which may begin with one or two alphabetic characters identifies the type of vehicle the tire is best suited to. E- stands for electric vehicles (such as electric bikes), whereas P- indicates passenger vehicles, L- stands for light truck and LT stands for light truck radial. The next component identifies the size measurements of the tire and encompasses aspect ratio, section width, wheel diameter and speed rating – all separated by hyphens or asterisks depending on manufacturer preference.

Finally, The last component S/T indicates whether it is a Standard Load or Special Trailer tire respectively when choosing trailer tires; using radials as opposed to bias ply designs is also a good choice here to ensure optimal performance over extended use in various terrains while carrying heavy loads safely.

How to Read Tire Sizes | United Tire & Service

Deciphering additional tire markings

In addition to the sizing information, a tire will have other markings. These are usually branded, but tell important information worth noting.

Load Index: This is an assigned numerical value that gives an indication of how much weight the tire is designed to carry. The higher the Load Index number, the more weight it can support in a single axle configuration.

Speed Rating: This indicates the maximum speed at which you can safely drive on the tires. Before exceeding this speed limit be sure to check your vehicle’s owner’s manual for any special requirements when going above this limit with your tires. Also, remember, it doesn’t matter how fast your car can go if you don’t take care of your brakes! Common letters associated with Speed Ratings include: -Q (up to 100 mph) -S (up to 112 mph) -T (up to 118 mph) -U (up to 124 mph) -H (up to 130 mph)

Runflat Technology: This allows a driver to continue driving on a flat or deflated tire after a puncture or blowout at reduced speeds and distances marked by the manufacturer. It’s worth noting that some manufacturers mandate that run flat tires must be replaced in pairs even if only one has sustained damage in order for them continue functioning effectively. Certain wheel designs also require specialty Runflat technology and should be investigated prior to purchase.

Additional markings on the tire sidewall, including load rating and speed rating

Other markings finely printed on the side wall of a tire provide clues to its identity and characteristics. While most tires just show basic information such as size and brand name, some have additional designations identifying their load ratings or speed rating locations. They may use numbers and/or codes, depending on the brand, which tells you what type of vehicle the tire is designed for, or in what conditions it can be safely operated. This information can be valuable if you are trying to determine if a certain tire is suitable for your vehicle or your driving requirements.

Load Rating: This number tells you how much weight each tire can safely carry when properly inflated. A higher number indicates that the tires have a higher load capacity and can safely support more weight than tires with lower numbers. The actual number may include a letter code that designates service descriptions such as “LT” (light truck) or “SL” (standard load).

Speed Rating: A letter appearing alongside the size designations on the sidewall specifies a maximum speed rating at which it can be driven under optimal conditions. It indicates that the tire’s construction is capable of sustaining its intended performance at speeds up to its rated limit. Different types of vehicles require different speed ratings; for example, most passenger cars require H-rated tires although some are designed to handle speeds up to Y (186+ mph) or Z (149+ mph).

Importance of understanding additional markings for proper tire selection

Knowing how to read and understand the tire size and type designation of passenger tires is essential when selecting new tires. There are three basic components to the tire sizing system, which include the tire width, aspect ratio and construction type. Additionally, there are several other markings that can provide important information about the intended use and other characteristics of a specific tire.

Width is given first in metric measurements and represents the distance from sidewall to sidewall at the widest point of a mounted tire. It’s important to note that section width will increase slightly as a tire is inflated beyond its recommended pressure.

The second number indicates the aspect ratio, or profile height as it relates to width, expressed as a percentage or 65 for example. This number tells how high the sidewall is compared to its section width. In this example, a 65-aspect ratio would be equal to nearly 65 percent of 215 mm or 140 mm. The higher this aspect ratio is, resulting in taller side walls; farther it will cushion your ride, but may cause excessive sway in your vehicle if driven aggressively or in inclement weather.

The third letter designates construction type: R stands for radials; B designates bias-belted; and D makes reference to bias-ply tires. Radials offer improved stability at higher speeds but tend to have increased rolling resistance compared with bias models; belted styles are usually lighter than bias types but more prone to tread squirm due to their less rigid construction; while constructions also provide improved handling capabilities over bias versions with enhanced steering precision and grip on dry roads – although their wet traction lags somewhat behind radials.

These additional markings will indicate certain tire characteristics such as maximum speed rating (D – 210 km/h), load index (93 – 600 kg) or UTQG ratings (220 AA A). Becoming familiar with these numbers shall help you make an informed decision when choosing tires for your vehicle.


By now, you should have a better understanding of tire size and type. Initially, the information can be intimidating. However, as you take the time to read through this guide, you begin to realize that there is a lot of information available to you.

Not only can this help when it comes time to purchase replacements for your vehicle, but it can also provide you with reassurance that you know what is under those tires and that they are the best for your make and model. Therefore, it is important for every vehicle owner to become familiar with tire size and type in order to make an informed decision when choosing new tires-one that will last through all weather conditions safely and securely.

Recap of how to read tire size and type

The type of tire is identified by markings on the sidewall and by the designation that appears on an accompanying tire label. Common designations include P (passenger cars), LT (light trucks) and T (temporary spare tires).

To read a tire size, you’ll need to look at the sidewall of your existing tires. There, you should be able to find three main pieces of information:.

  1. Width – This is listed first in a combination of numbers and letters like 205/65 R 15 94H. The width measures the distance across the outer surface of the tire from sidewall to sidewall in millimeters when it is mounted.
  2. Aspect Ratio – This comes after the slash (/) and expresses a percentage relationship between section height and width; in this case, 65%. It is basically the height from wheel rim to tread surface expressed as a percentage of width from one side to across the other side. This will identify how tall your tire needs to be for proper fitment on your vehicle’s current wheel size. The higher this number, i.e., 75 versus 35 series, will indicate a taller than normal tire which allows for greater absorption when driving over bumps or rough spots due to its larger sidewalls giving it more flexibility.
  3. Construction – This letter indicates how many plies are wrapped around each tire body cord layer along with what material these cords are made from; in this example: R = Radial construction composed with Steel belts parts.
  4. Wheel Diameter -This is usually indicated as an inch measurement like 18 or 20 inches with no fractional numerator values. The literal size of a wheel you’d be looking for when shopping for replacement tires if yours are worn out or need replacing due to age should match your current wheels diameter value exactly for compatibility purposes on most front-wheel drive vehicles. However if you wanted more grip or were looking into certain performance modifications that allow larger than standard sized wheels than those listed here would still be compatible ones but they’d have different rolling circumference measurements which could lead to gear ratio miscalculations if installed without being accounted for properly since each vehicle has different gear ratios optimized for various speed ranges per engine type used & other factors specific to each make& model. Remember that changing up too much can also cause physical clearance issues depending on suspension setup & overall suspension travel distance available per lift kit capabilities & length tolerances set forth by manufacturer so always research thoroughly before making any changes!

How To Read Tire Size | Tire Size Meaning | Tire Size Explained | How To Read Tire Numbers | Reading Tire Sizes | Discount Tire

Final recommendations for selecting, maintaining, and caring for your tires.

Once you’ve chosen the right set of tires for your car or truck, verifying that they are the correct size and type of tire is critical to ensuring your vehicle has the best performance. You can find this information on the sidewall by looking at a combination of letters and numbers. This guide provides a full guide to understanding tire size and type so that you have all the information you need to keep your car or truck safe and well-maintained.

Once you have selected, bought, or have been sold a tire, it is important to check:

  • The load index number matches what was recommended by your manufacturer.
  • The speed ratings match those prescribed by your manufacturer.
  • It has an adequate tread depth with at least 2/32” remaining while still being legal in your area (6/32” is often cited as optimum tread depth).
  • There is no visible damage such as dehousing, cuts, punctures, sidewall bubbles, or excessive cracking.
  • Your spare tire (if any) has enough air pressure and that it matches with all other tires regardless of brand name (for proper wheel balance).
  • You install two tires of identical design and size on each axle for improved handling.

It is also essential to remember to maintain correct pressures in all four tires; any changes should be made equally for both axles so as not to displace wheel alignment configurations nor put too much strain or uneven load onto one axle where its components could easily become damaged over time from consistent use on an unbalanced wheel setup. Finally, it is always wise to practice proper care and maintenance; rotating tires regularly per vehicle manufacturer guidelines can help ensure maximum service life from them depending on their construction materials used.

See Also :

Leave a Comment