wheel and tire chart to determine what will fit on my car

How To Determine Tire Size

Once you lot accept determined information technology's fourth dimension to buy tires, you'll need to know what size tires are right for your vehicle. This information is usually inside your car's doorjamb, in your owner's transmission. To ensure your current tire or a replacement tire you may exist looking at matches your vehicle's requirements, information technology will be practiced for your to empathize how tire sizing works. You lot may have never paid attention to the string of numbers and messages on every tire, merely information technology'south a gold mine of information.

If you're unsure of how to read tire measurements from your tire walls, the information and graphics beneath will tell you how to read tire size, understand and interpret it. If y'all decide you want to substitute a new size or tire type, consult an authorized tire retailer who can expertly advise y'all, because many optional tire sizes may have different load capacities and could require wheels of a dissimilar rim width or diameter and different inflation pressure.

Metric Sizing

Most passenger cars, SUVs and light pickups (1/2 ton and smaller) will come with tires that are either P-Metric or Euro-Metric. For P-Metric tires, you'll run into the letter "P" before the number sequence begins: P225/70R16 97H. P-metric is a designation standardized past the Tire and Rim Association for a "passenger car" tire type. For Euro-Metric there volition exist no preceding letter of the alphabet earlier the number sequence begins: 225/70R16 98H. Euro-Metric is a designation standardized by the European Tyre and Rim Technical Organization for a "passenger car" tire blazon.  Both P-Metric and Euro-Metric size tires are designed to primarily exist used on passenger vehicles, which can include cars, minivans, SUVs, and other light duty pickup trucks.

If your vehicle is an SUV, Pickup truck or van, yous might see a different type of size designation on your placard that is specific for heavy duty low-cal trucks and vans, peculiarly common on ¾ ton and larger pickup trucks and vans. There are ii common size types in this category, LT-Metric and Euro-Metric Commercial (aka C-type). Both size types are metric and then utilise the same structure equally P-Metric and Euro-Metric but take some different characters in the size that differentiate them from their passenger car cousins. LT-Metric tires volition have the messages "LT" before the size number sequence: LT245/75R17 119/116R Load Range E. Find that at that place are two load index numbers and a Load Range, run into the section on Load Index for more info.  LT-Metric is a designation standardized by the Tire and Rim Association for a "light truck" type tire. Euro-Metric Commercial or C-Type tires volition await very similar to a rider Euro-Metric size except that there will be a "C" right after the rim size: 23/65R16C 121/119R. Discover that the C-type tires also have two load index numbers. Euro-Metric Commercial, or C-Blazon is a designation standardized by the European Tyre and Rim Technical Organization for a light truck type tire. Calorie-free truck tires are designed to exist used on vehicles capable of carrying heavy cargo and are normally simply specified past a vehicle manufacturer on vehicles exceeding a certain load capacity.

Other types of tires that fall into the Metric sizing type are Temporary Spares, they kickoff with "T". If you see a size that starts with "ST," that means "special trailer" and is only for employ on a trailer.

Regardless of whether you are looking at a P-Metric, Euro-Metric, LT-Metric, Euro-Metric Commercial, T or ST tire the numbers in the size mean the same matter.

Width

The first number to appear in your tire size information is the width, in millimeters, of the correct tires for your vehicle: P225/70R16 91S.

Tire width e'er refers to the measurement from 1 sidewall to another. Thus, a tire with the measurement "P225" is for a passenger vehicle and has a nominal width of 225 millimeters.

Attribute Ratio

Afterward the slash mark, the next number you come across is for the tire'southward attribute ratio, which substantially tells you how tall your tire's profile is: P225/70R16 91S. Aspect ratios are delivered in percentages. Tire makers calculate the aspect ratio past dividing a tire'due south meridian off the rim past its width. If a tire has an aspect ratio of seventy, it ways the tire'south height is 70% of its width.

Lower aspect ratio tires, such equally a 60 serial, generally offer vehicle handling performance advantages over higher attribute ratio tires, such as a 75 series, but a typical trade off tin can exist ride harshness.

Construction

Later on the aspect ratio comes a letter that indicates the type of internal structure maintaining your tire's stability: P225/70R16 91S.

At that place are two types of construction that you may see on the sidewall of a tire:

• R – Radial
• D or "B" or "-" – Diagonal or Bias Ply

Radial tires are the most mutual tires on the route in the United States today; thus "R" will usually be shown in the tire size designation. Radial structure means the tire's internal ply cords are oriented in a radial direction, from one bead over to the other, essentially perpendicular to the management of rotation. You may also occasionally see RF indicating a run flat tire or ZR indicating a tire that is a speed rating college than V.

Rim Diameter

The side by side number is the diameter lawmaking, in inches, of the rim onto which the tire tin be mounted. For example, a tire with the P225/70R16 91S would fit a rim with a 16-inch diameter.

Load Index

Load index can be a disruptive subject field because in that location are so many different caveats, but we will effort to explain everything here.

The adjacent effigy subsequently the rim size in the sequence is your tire'south load index, which tells the states how much weight, in pounds, the tire can support when fully inflated: P225/70R16 91S

We call it the load "index" because the number doesn't tell the states the precise number of pounds the tire tin can carry, at to the lowest degree not by itself. Yet, the number does stand for to a specific load capacity listed in an index. Beginning with 1 and ending with 150, numbers in the load alphabetize correspond carrying capacities of 99 to 7385 lbs.

There are ii types of load types for passenger tires though, Standard Load and Extra Load. If a tire is Standard Load there will be no markings indicating it but if it is Extra Load the letters XL will appear after the size and load alphabetize.

Standard Load Euro-Metric: 215/55R17 94V

Extra Load Euro-Metric: 215/55R17 98V Forty

Rider motorcar tires like P-Metric and Euro-Metric will only take i load index number where LT-Metric and Euro-Metric Commercial (C-Type) will accept two numbers separated by a slash. The first number is the load alphabetize if the tire is used in a single application, the second number is the load index if the tire is used in a dual application. Passenger blazon tires cannot be used in a dual awarding. Light truck tires will also have a Load Range that is indicated past a letter of the alphabet, such every bit Load Range East. Load Range is an older term that is still commonly used in the manufacture so you may hear your tire dealer reference it but the load index numbers are the all-time style to ensure you lot have the proper tire.

1 of import merely ofttimes misunderstood facet about load alphabetize is that the load alphabetize numbers between standards organizations (P-Metric vs Euro-Metric) are not necessarily on the same calibration. Meaning that two tires in the two different systems that have the same load alphabetize number could have different maximum load capacities. This is why information technology's important to not just await at the load index number but also verify the bodily load chapters.

Speed Rating

The final figure in a tire size sequence is the speed rating, which is indicated past a letter of the alphabet: P225/70R16 91S. But every bit your load index number corresponds to a specific load, your speed rating letter corresponds to a particular speed capability based on a standardized laboratory test.

For example, a tire with speed rating "Due south" is rated for up to 112 mph, while a tire rated "R" is up to 106 mph. Remember that this isn't a recommended cruising speed. Of form, you should always follow legal speed limits on roadways.

Replacement tires must take the aforementioned or higher speed rating as the vehicle'south Original Equipment to maintain vehicle speed capability. If a vehicle has tires with different speed ratings, information technology is the speed rating of the "slowest" tire that dictates the vehicle top speed.

Flotation Sizing

There is one last sizing type that you should know well-nigh, especially if yous are in the market place for off road tires for a light truck or SUV. Information technology'southward chosen a Flotation size and the numbers in this sizing format are very unlike from the Metric formats. Flotation sized tires are similar to LT-Metric tires in application except for a few important points. Number i, they cannot exist used in dual applications and number two, an equivalent size tire may have different load capacity than its LT-Metric counterpart.

Overall Bore

The start number in the Flotation tire size is the overall diameter in inches. Pretty directly forward.

Section Width

The second number is the department width (sidewall to sidewall) measurement in inches. Once again, fairly unproblematic.

Construction

Later on the section width comes a letter that indicates the blazon of internal structure: 33X12.50R17LT 120Q.

This is the same as is establish in the metric sizing systems.

There are two types of structure that you may see on the sidewall of a tire:

• R – Radial
• D or "B" or "-" – Diagonal or Bias Ply

Radial tires are the virtually common tires on the route in the United States today; thus "R" volition usually be shown in the tire size designation. Radial construction means the tire's internal ply cords are oriented in a radial management, from one bead over to the other, essentially perpendicular to the direction of rotation.

Rim Diameter

The adjacent number is the bore lawmaking, in inches, of the rim onto which the tire can exist mounted. For example, a tire with the 33X12.50R17LT 120Q would fit a rim with a 17-inch diameter.

LT type

The letters LT will be after the Rim Diameter indicating that this tire blazon is intended for Light Truck vehicles similar to the LT-Metric and Euro-Metric Commercial (C-Blazon) tires.

Load Alphabetize and Speed Rating

Load Index and Speed Rating have the aforementioned meaning and format as the tires using the metric sizing system. Notation that since flotation tires cannot be used in a dual application at that place will be simply one load index number instead of ii.

Uniform Tire Quality Grading

Some other grouping of stamping on certain types of tires is the Uniform Tire Quality Grading or UTQG. This grading and stamping is required for passenger car tires (i.e. P-metric and Euro-metric) in the all season and summertime categories. Dedicated winter tires, Calorie-free Truck (LT-Metric, Euro-Metric Commercial, Flotation) and Motorcycle tires are excluded from this requirement.

Quality grading is designed to brand the tire purchase conclusion easier for you. Ideally, the arrangement is intended to provide simple, comparative data so you can make an intelligent buying decision. However, the ratings are based upon test results achieved under special conditions. This means it'southward possible to misinterpret the comparative data as it relates to your individual driving habits, conditions, etc. Yous should notwithstanding rely on your service or tire professional for aid.

Quality grading designates the comparative functioning levels of a tire based on government-specified tests simply commissioned by the private tire manufacturers. All tire manufacturers are required to form regular and all-flavor passenger tires in three categories:

UTQG

1. Treadwear
2. Traction
3. Temperature

Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government exam class for half-dozen,000 miles (nine,600 km). For example, a tire graded 150 would article of clothing one and a half times as well on the government course as a tire graded 100. Nevertheless bodily tire performance depends on driving habits, road characteristics, service practices, and other factors that tin influence the upshot.

Traction Grades AA, A, B and C
The traction grades from highest to everyman are AA (the highest), A, B and C. They represent how well tires stop on wet pavement as measured nether controlled conditions on specified regime test surfaces of cobblestone and concrete. C-rated tires will have the lowest traction performance.

Alert: THE TRACTION Class ASSIGNED IS BASED ON A Moisture BRAKING (STRAIGHT AHEAD) TRACTION TEST AND DOES NOT INCLUDE CORNERING (TURNING) TRACTION.

Temperature Grades A, B and C
The temperature grades A, B, and C stand for the tire's resistance to the generation of heat and its ability to misemploy rut when tested under controlled weather on a specified indoor laboratory examination wheel. Sustained high temperature can cause the tire'southward fabric to degenerate and reduce tire life, and excessive temperature tin can lead to sudden tire failure. The grade C corresponds to a performance level all passenger car tires must meet under the Federal Motor Vehicle Prophylactic Standard No. 109. Grades A and B correspond higher levels of operation on the laboratory test bike than the minimum required past constabulary.

WARNING: THE TEMPERATURE GRADE IS ESTABLISHED FOR A TIRE THAT IS PROPERLY INFLATED AND Non OVERLOADED. EXCESSIVE SPEED, Nether Aggrandizement, OR EXCESSIVE LOADING, EITHER SEPARATELY OR IN COMBINATION, CAN CAUSE HEAT BUILDUP AND POSSIBLE TIRE FAILURE.

DOT Quality Grades
All rider machine tires must suit to other federal requirements in addition to these grades.

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Source: https://www.bridgestoneamericas.com/en/company/safety/choosing-tires/determining-tire-size

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