How to know tire diameter


How to Read & Determine Tire Size for Your Vehicle

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How To Determine Tire Size

Once you have determined it’s time to buy tires, you’ll need to know what size tires are correct for your vehicle. Depending on what you drive, you may be interested in how to find the right tire for your…  

  • Sedans or CUV
  • Light Trucks or SUV
  • Motorcycle
  • RV

This information is usually inside your car’s doorjamb, in your owner’s manual. To ensure your current tire or a replacement tire you may be looking at matches your vehicle’s requirements, it will be good for you to understand how tire sizing works. You may have never paid attention to the string of numbers and letters on every tire, but it’s a gold mine of information.

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

Not sure you need new tires? Our Tire Replacement Guidance article will help you determine whether it’s time to retire your tires.

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 see the letter “P” before the number sequence begins: P225/70R16 97H. P-metric is a designation standardized by the Tire and Rim Association for a “passenger car” tire type. For Euro-Metric there will be no preceding letter before 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 type.  Both P-Metric and Euro-Metric size tires are designed to primarily be 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, you might see a different type of size designation on your placard that is specific for heavy duty light trucks and vans, especially common on ¾ ton and larger pickup trucks and vans. There are two common size types in this category, LT-Metric and Euro-Metric Commercial (aka C-type). Both size types are metric and so use the same structure as P-Metric and Euro-Metric but have some different characters in the size that differentiate them from their passenger car cousins. LT-Metric tires will have the letters “LT” before the size number sequence: LT245/75R17 119/116R Load Range E. Notice that there are two load index numbers and a Load Range, see 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 will look very similar to a passenger Euro-Metric size except that there will be a “C” right after the rim size: 23/65R16C 121/119R. Notice that the C-type tires also have two load index numbers. Euro-Metric Commercial, or C-Type is a designation standardized by the European Tyre and Rim Technical Organization for a light truck type tire. Light truck tires are designed to be used on vehicles capable of carrying heavy cargo and are usually only specified by 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 start with “T”. If you see a size that starts with “ST,” that means “special trailer” and is only for use 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 thing.

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 always refers to the measurement from one sidewall to another. Thus, a tire with the measurement “P225” is for a passenger vehicle and has a nominal width of 225 millimeters.

Aspect Ratio

After the slash mark, the next number you see is for the tire’s aspect ratio, which essentially tells you how tall your tire’s profile is: P225/70R16 91S. Aspect ratios are delivered in percentages. Tire makers calculate the aspect ratio by dividing a tire’s height off the rim by its width. If a tire has an aspect ratio of 70, it means the tire’s height is 70% of its width.

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

Construction

After the aspect ratio comes a letter that indicates the type of internal construction maintaining your tire’s stability: P225/70R16 91S.

There 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 common tires on the road in the United States today; thus “R” will usually be shown in the tire size designation. Radial construction means the tire’s internal ply cords are oriented in a radial direction, from one bead over to the other, essentially perpendicular to the direction of rotation. You may also occasionally see RF indicating a run flat tire or ZR indicating a tire that is a speed rating higher than V.

Rim Diameter

The next number is the diameter code, in inches, of the rim onto which the tire can 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 confusing subject because there are so many different caveats, but we will try to explain everything here.

The next figure after the rim size in the sequence is your tire’s load index, which tells us 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 us the precise number of pounds the tire can carry, at least not by itself. However, the number does correspond to a specific load capacity listed in an index. Beginning with 1 and ending with 150, numbers in the load index represent carrying capacities of 99 to 7385 lbs.

There are two 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 index.

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

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

Passenger car tires like P-Metric and Euro-Metric will only have one load index number where LT-Metric and Euro-Metric Commercial (C-Type) will have two numbers separated by a slash. The first number is the load index 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 type tires cannot be used in a dual application. Light truck tires will also have a Load Range that is indicated by a letter, such as Load Range E. Load Range is an older term that is still commonly used in the industry so you may hear your tire dealer reference it but the load index numbers are the best way to ensure you have the proper tire.

One important but often misunderstood facet about load index is that the load index numbers between standards organizations (P-Metric vs Euro-Metric) are not necessarily on the same scale. Meaning that two tires in the two different systems that have the same load index number could have different maximum load capacities. This is why it’s important to not only look at the load index number but also verify the actual load capacity.

Speed Rating

The final figure in a tire size sequence is the speed rating, which is indicated by a letter: P225/70R16 91S. Just as 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 “S” 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 course, you should always follow legal speed limits on roadways.

Replacement tires must have the same or higher speed rating as the vehicle’s Original Equipment to maintain vehicle speed capability. If a vehicle has tires with different speed ratings, it 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 about, especially if you are in the market for off road tires for a light truck or SUV. It’s called a Flotation size and the numbers in this sizing format are very different from the Metric formats. Flotation sized tires are similar to LT-Metric tires in application except for a few important points. Number one, they cannot be used in dual applications and number two, an equivalent size tire may have different load capacity than its LT-Metric counterpart.

Overall Diameter

The first number in the Flotation tire size is the overall diameter in inches. Pretty straight forward.

Section Width

The second number is the section width (sidewall to sidewall) measurement in inches. Again, fairly simple.

Construction

After the section width comes a letter that indicates the type of internal construction: 33X12.50R17LT 120Q.

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

There 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 common tires on the road in the United States today; thus “R” will usually be shown in the tire size designation. Radial construction means the tire’s internal ply cords are oriented in a radial direction, from one bead over to the other, essentially perpendicular to the direction of rotation.

Rim Diameter

The next number is the diameter code, in inches, of the rim onto which the tire can be 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 type is intended for Light Truck vehicles similar to the LT-Metric and Euro-Metric Commercial (C-Type) tires.

Load Index and Speed Rating

Load Index and Speed Rating have the same meaning and format as the tires using the metric sizing system. Note that since flotation tires cannot be used in a dual application there will be only one load index number instead of two.  

Uniform Tire Quality Grading

Another group 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 summer categories. Dedicated winter tires, Light Truck (LT-Metric, Euro-Metric Commercial, Flotation) and Motorcycle tires are excluded from this requirement.

Quality grading is designed to make the tire purchase decision easier for you. Ideally, the system 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’s possible to misinterpret the comparative data as it relates to your individual driving habits, conditions, etc. You should still rely on your service or tire professional for assistance. 

Quality grading designates the comparative performance levels of a tire based on government-specified tests but commissioned by the individual tire manufacturers. All tire manufacturers are required to grade regular and all-season 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 test course for 6,000 miles (9,600 km). For example, a tire graded 150 would wear one and a half times as well on the government course as a tire graded 100. However actual tire performance depends on driving habits, road characteristics, service practices, and other factors that can influence the outcome. 

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

WARNING: THE TRACTION GRADE ASSIGNED IS BASED ON A WET 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 represent the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the tire’s material to degenerate and reduce tire life, and excessive temperature 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 Safety Standard No. 109. Grades A and B represent higher levels of performance on the laboratory test wheel than the minimum required by law. 

WARNING: THE TEMPERATURE GRADE IS ESTABLISHED FOR A TIRE THAT IS PROPERLY INFLATED AND NOT OVERLOADED. EXCESSIVE SPEED, UNDER INFLATION, OR EXCESSIVE LOADING, EITHER SEPARATELY OR IN COMBINATION, CAN CAUSE HEAT BUILDUP AND POSSIBLE TIRE FAILURE.

DOT Quality Grades 
All passenger car tires must conform to other federal requirements in addition to these grades.

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Tire Size Calculator

Tire Size Calculator Chart for 13" Wheels

21" Tire Diameter
185/60R13 = 21.7x7.3R13
215/50R13 = 21.5X8.5R13
225/45R13 = 21x8.9R13
225/50R13 = 21.9x8.9R13
255/40R13 = 21x10R13

22" Tire Diameter
155/80R13 = 22.8x6.1R13
175/70R13 = 22.6x6.9R13
205/60R13 = 22.7x8.1R13
22X8R13

23" Tire Diameter
165/80R13 = 23.4X6.5R13
185/70R13 = 23.2x7.3R13

24" Tire Diameter
175/80R13 = 24x6.9R13
185/80R13 = 24.7x7.3R13
24.5X8R13
24.5X9R13

Tire Size Calculator Chart for 14" Wheels

19" Tire Diameter
105/70R14 = 19.8X4.1R14

20" Tire Diameter
115/70R14 = 20. 3X4.5R14
125/70R14 = 20.9X4.9R14

21" Tire Diameter
165/55R14 = 21.1X6.5R14

22" Tire Diameter
135/80R14 = 22.5X5.3R14
165/65R14 = 22.4x6.5R14
185/55R14 = 22x7.3R14
185/60R14 = 22.7x7.3R14
195/55R14 = 22.4x7.7R14
205/50R14 = 22.1x8.1R14
205/55R14 = 22.9x8.1R14
225/50R14 = 22.9x8.9R14

23" Tire Diameter
175/65R14 = 23x6.9R14
175/70R14 = 23.6x6.9R14
185/65R14 = 23.5x7.3R14
195/60R14 = 23.2x7.7R14
205/60R14 = 23.7x8.1R14

24" Tire Diameter
185/70R14 = 24.2x7.3R14
185/75R14 = 24.9X7.3R14
195/65R14 = 24x7.7R14
195/70R14 = 24.7x7.7R14
215/60R14 = 24.2x8.5R14
225/60R14 = 24.6x8.9R14

25" Tire Diameter
185R14 = 25.7x7.3R14
195/75R14 = 25.5x7.7R14
205/70R14 = 25.3x8.1R14
215/70R14 = 25.9x8.5R14
235/60R14 = 25.1x9.3R14
245/60R14 = 25.6x9.6R14

26" Tire Diameter
195R14 = 26.2x7.8R14
205/75R14 = 26. 1x8.1R14
215/75R14 = 26.7x8.5R14
225/70R14 = 26.4x8.9R14
26X8.5R14

27" Tire Diameter
205R14 = 27x8.2R14
27X8.5R14
27X9.5R14

28" Tire Diameter
28X10R14

30" Tire Diameter
30X10R14

Tire Size Calculator Chart for 15" Wheels

20" Tire Diameter
105/70R15 = 20.8X4.1R15

21" Tire Diameter
115/70R15 = 21.3X4.5R15
125/70R15 = 21.9X4.9R15
165/50R15 = 21.5X6.5R15
195/45R15 = 21.9x7.7R15

22" Tire Diameter
125/80R15 = 22.9X4.9R15
145/65R15 = 22.4x5.7R15
155/60R15 = 22.3x6.1R15
165/60R15 = 22.8x6.5R15
175/55R15 = 22.6x6.9R15
195/50R15 = 22.7x7.7R15
22X8R15
22.5X4.5R15
245/40R15 = 22.7X9.6R15
275/35R15 = 22.6x10.8R15

23" Tire Diameter
135/80R15 = 23.5X5.3R15
165/65R15 = 23.4X6.5R15
175/60R15 = 23.3x6.9R15
185/55R15 = 23x7.3R15
185/60R15 = 23.7x7.3R15
195/55R15 = 23.4x7.7R15
205/50R15 = 23. 1x8.1R15
205/55R15 = 23.9x8.1R15
225/45R15 = 23x8.9R15
225/50R15 = 23.9x8.9R15
295/35R15 = 23.1X11.6R15

24" Tire Diameter
135/90R15 = 24.6X5.3R15
155/80R15 = 24.8X6.1R15
175/65R15 = 24x6.9R15
185/65R15 = 24.5x7.3R15
195/60R15 = 24.2x7.7R15
205/60R15 = 24.7x8.1R15
225/55R15 = 24.7x8.9R15
235/50R15 = 24.3x9.3R15
24X4.5R15
24X5R15
24.5X8R15
245/50R15 = 24.6x9.6R15
345/35R15 = 24.5x13.6R15

25" Tire Diameter
165/80R15 = 25.4X6.5R15
185/70R15 = 25.2x7.3R15
195/65R15 = 25x7.7R15
195/70R15 = 25.7x7.7R15
205/65R15 = 25.5x8.1R15
215/60R15 = 25.2x8.5R15
225/60R15 = 25.6x8.9R15
265/50R15 = 25.4X10.4R15
275/50R15 = 25.8x10.8R15

26" Tire Diameter
205/70R15 = 26.3x8.1R15
215/65R15 = 26x8.5R15
215/70R15 = 26.9x8.5R15
235/60R15 = 26.1x9.3R15
245/60R15 = 26.6x9.6R15
26X10R15
26X10.5R15
26X11.5R15
26X6R15
26X7.5R15
26X8R15
26X8. 5R15
295/50R15 = 26.6x11.6R15

27" Tire Diameter
205/75R15 = 27.1x8.1R15
215/75R15 = 27.7x8.5R15
225/70R15 = 27.4x8.9R15
255/60R15 = 27x10R15
27X10.5R15
27X9.5R15
27.5X4.5R15
295/55R15 = 27.8X11.6R15
325/50R15 = 27.8x12.8R15
E78-15 = 27x6.5R15

28" Tire Diameter
225/75R15 = 28.3x8.9R15
235/70R15 = 28x9.3R15
235/75R15 = 28.9x9.3R15
245/70R15 = 28.5X9.6R15
255/65R15 = 28.1x10R15
275/60R15 = 28x10.8R15
28X10.5R15
28X11.5R15
28X12.5R15
28X13.5R15
28X4.5R15
28X7.5R15
28X9R15

29" Tire Diameter
215/85R15 = 29.4X8.5R15
255/70R15 = 29.1x10R15
265/70R15 = 29.6x10.4R15
29X10.5R15
29X11.5R15
29X12.5R15
29X15.5R15
29X18R15
29X18.5R15
29X4.5R15
29X8.5R15
29.5X11.5R15
29.5X13.5R15
29.5X9R15
315/60R15 = 29.9x12.4R15
7R15 = 29.5x7.7R15

30" Tire Diameter
255/75R15 = 30.1x10R15
265/75R15 = 30. 6x10.4R15
295/65R15 = 30.1x11.6R15
30X10R15
30X10.5R15
30X11.5R15
30X12.5R15
30X13.5R15
30X7R15
30X9R15
30X9.5R15

31" Tire Diameter
31X10.5R15
31X11R15
31X11.5R15
31X12.5R15
31X13R15
31X13.5R15
31X14.5R15
31X16.5R15
31X18R15
31X18.5R15
31X9.5R15

32" Tire Diameter
32X10.5R15
32X11.5R15
32X14R15
32X16R15
32X17.5R15
32X18.5R15
32X9.5R15

33" Tire Diameter
33X10.5R15
33X11.5R15
33X12.5R15
33X13R15
33X13.5R15
33X14R15
33X14.5R15
33X15.5R15
33X16.5R15
33X19.5R15
33X21.5R15
33X9R15
33X9.5R15

34" Tire Diameter
34X10.5R15
34X12.5R15
34X9.5R15

35" Tire Diameter
35X10.5R15
35X12.5R15
35X13.5R15
35X14.5R15
35X15R15
35X15.5R15
35X16R15

36" Tire Diameter
36X12.5R15
36X13.5R15
36X14.5R15

37" Tire Diameter
37X12. 5R15
37X13R15
37X13.5R15
37X14R15
37X14.5R15

38" Tire Diameter
38X12.5R15
38X13R15
38X14.5R15
38X15.5R15
38.5X11R15
38.5X13.5R15
38.5X14.5R15
38.5X15R15
38.5X16R15

39" Tire Diameter
39X13.5R15
39.5X13.5R15
39.5X15R15
39.5X18R15

40" Tire Diameter
40X16R15

42" Tire Diameter
42X14R15
42X15R15
42.5X13.5R15

44" Tire Diameter
44X18.5R15
44X19.5R15
44X21R15

47" Tire Diameter
47X17R15

Tire Size Calculator Chart for 16" Wheels

22" Tire Diameter
125/70R16 = 22.9X4.9R16
175/50R16 = 22.9x6.9R16
195/40R16 = 22.1x7.7R16
195/45R16 = 22.9x7.7R16
205/40R16 = 22.5x8.1R16
215/35R16 = 21.9x8.5R16
215/40R16 = 22.8x8.5R16

23" Tire Diameter
125/80R16 = 23.9X4.9R16
135/70R16 = 23.4X5.3R16
175/55R16 = 23.6x6.9R16
185/50R16 = 23.3X7.3R16
195/50R16 = 23. 7x7.7R16
205/45R16 = 23.3x8.1R16
215/45R16 = 23.6x8.5R16

24" Tire Diameter
125/85R16 = 24.4X4.9R16
125/90R16 = 24.9X4.9R16
135/80R16 = 24.5X5.3R16
175/60R16 = 24.3x6.9R16
185/55R16 = 24x7.3R16
185/60R16 = 24.7X7.3R16
195/55R16 = 24.4x7.7R16
205/50R16 = 24.1x8.1R16
205/55R16 = 24.9x8.1R16
215/50R16 = 24.5X8.5R16
225/45R16 = 24x8.9R16
225/50R16 = 24.9x8.9R16
245/45R16 = 24.7x9.6R16

25" Tire Diameter
135/90R16 = 25.6X5.3R16
145/80R16 = 25.1X5.7R16
195/60R16 = 25.2x7.7R16
205/60R16 = 25.7x8.1R16
215/55R16 = 25.3x8.5R16
225/55R16 = 25.7x8.9R16
245/50R16 = 25.6x9.6R16
265/45R16 = 25.4X10.4R16
275/45R16 = 25.7x10.8R16
315/40R16 = 25.9X12.4R16

26" Tire Diameter
145/90R16 = 26.3X5.7R16
145/90R16 = 26.3X5.7R16
195/65R16 = 26X7.7R16
205/65R16 = 26.5x8.1R16
215/60R16 = 26.2x8.5R16
225/60R16 = 26.6x8.9R16
235/55R16 = 26.2x9.3R16
255/50R16 = 26x10R16
26X11. 5R16

27" Tire Diameter
155/90R16 = 27X6.1R16
195/75R16 = 27.5x7.7R16
205/70R16 = 27.3x8.1R16
215/65R16 = 27x8.5R16
215/70R16 = 27.9x8.5R16
225/65R16 = 27.5x8.9R16
235/60R16 = 27.1x9.3R16
295/50R16 = 27.6x11.6R16
355/40R16 = 27.2X14R16

28" Tire Diameter
195/80R16 = 28.3x7.7R16
205/75R16 = 28.1X8.1R16
205/80R16 = 28.9x8.1R16
215/75R16 = 28.7x8.5R16
225/70R16 = 28.4x8.9R16
235/65R16 = 28x9.3R16
255/60R16 = 28x10R16
28X11.5R16

29" Tire Diameter
225/75R16 = 29.3x8.9R16
235/70R16 = 29x9.3R16
235/75R16 = 29.9x9.3R16
245/70R16 = 29.5x9.6R16
255/65R16 = 29.1x10R16
275/60R16 = 29X10.8R16
285/60R16 = 29.5X11.2R16

30" Tire Diameter
215/85R16 = 30.4x8.5R16
235/80R16 = 30.8x9.3R16
245/75R16 = 30.5x9.6R16
255/70R16 = 30.1x10R16
265/70R16 = 30.6x10.4R16
285/65R16 = 30.6X11.2R16
30X11.5R16

31" Tire Diameter
225/85R16 = 31. 1X8.9R16
235/85R16 = 31.7x9.3R16
265/75R16 = 31.6x10.4R16
275/70R16 = 31.2x10.8R16
285/70R16 = 31.7x11.2R16
31X10.5R16
31X11R16
31X11.5R16
31X12.5R16
7.5R16 = 31.8x8.7R16

32" Tire Diameter
265/80R16 = 32.7X10.4R16
285/75R16 = 32.8x11.2R16
305/70R16 = 32.8x12R16
32X10R16
32X11.5R16
32X9R16

33" Tire Diameter
255/85R16 = 33.1x10R16
295/75R16 = 33.4x11.6R16
33X10.5R16
33X11.5R16
33X12.5R16
33X13R16
33X13.5R16
33X14R16
33X14.5R16
33X9.5R16
33.5X16.5R16

34" Tire Diameter
315/75R16 = 34.6x12.4R16
34X10.5R16
34X12.5R16
34X13.5R16
34X9R16
34.5X17R16

35" Tire Diameter
35X10.5R16
35X12.5R16
35X14.5R16
35X15R16
35X16R16
375/65R16 = 35.2x14.8R16

36" Tire Diameter
325/80R16 = 36.5x12.8R16
345/75R16 = 36.4x13.6R16
36X12.5R16
36X13R16
36X13.5R16
36X14. 5R16

37" Tire Diameter
365/75R16 = 37.6x14.4R16
37X12.5R16
37X13R16
37X13.5R16
37X14R16
37X14.5R16
385/70R16 = 37.2x15.2R16
395/70R16 = 37.8x15.6R16

38" Tire Diameter
38X13R16
38X14.5R16
38X15.5R16
38.5X11R16
38.5X13.5R16
38.5X14.5R16
38.5X15R16

39" Tire Diameter
39X13.5R16
39.5X13.5R16
39.5X15R16

40" Tire Diameter
40X16R16

41" Tire Diameter
41X14.5R16

42" Tire Diameter
42X14R16
42X15R16
42.5X13.5R16

44" Tire Diameter
44X19.5R16
44X21R16

46" Tire Diameter
46X19.5R16

Tire Size Calculator Chart for 16.5" Wheels

29" Tire Diameter
8.75R16.5 = 29.5x8.8R16.5

30" Tire Diameter
9.5R16.5 = 30.6x9.5R16.5

32" Tire Diameter
32X12R16.5

33" Tire Diameter
33X11.5R16.5
33X12.5R16.5
33X14R16. 5
33X14.5R16.5
33X15.5R16.5

35" Tire Diameter
35X12.5R16.5
35X14.5R16.5
35X15R16.5
35X15.5R16.5
35X16R16.5
35X9.5R16.5

36" Tire Diameter
36X12.5R16.5
36X13.5R16.5
36X14.5R16.5
36X16R16.5

37" Tire Diameter
37X12.5R16.5
37X13R16.5
37X14R16.5

38" Tire Diameter
38X11R16.5
38X12.5R16.5
38X15.5R16.5
38.5X11R16.5
38.5X13.5R16.5
38.5X14.5R16.5
38.5X15R16.5
38.5X16R16.5

39" Tire Diameter
39X13.5R16.5
39.5X13.5R16.5
39.5X15R16.5
39.5X18R16.5

42" Tire Diameter
42X14R16.5
42X15R16.5
42.5X13.5R16.5

43" Tire Diameter
43X14.5R16.5

44" Tire Diameter
44X18.5R16.5
44X18.5R16.5
44X19.5R16.5
44X21R16.5

47" Tire Diameter
47X17R16.5

48" Tire Diameter
48X12.5R16.5

49" Tire Diameter
49X21R16. 5

Tire Size Calculator Chart for 17" Wheels

22" Tire Diameter
22X2.5R17

23" Tire Diameter
125/70R17 = 23.9X4.9R17
195/40R17 = 23.1x7.7R17
195/45R17 = 23.9x7.7R17
205/40R17 = 23.5x8.1R17
215/35R17 = 22.9x8.5R17
215/40R17 = 23.8x8.5R17
225/35R17 = 23.2x8.9R17
245/35R17 = 23.8x9.6R17

24" Tire Diameter
125/80R17 = 24.9X4.9R17
135/70R17 = 24.4X5.3R17
205/45R17 = 24.3x8.1R17
215/45R17 = 24.6x8.5R17
225/40R17 = 24.1x8.9R17
235/40R17 = 24.4x9.3R17
245/40R17 = 24.7x9.6R17
275/35R17 = 24.6x10.8R17

25" Tire Diameter
115/95R17 = 25.6X4.5R17
135/80R17 = 25.5X5.3R17
145/70R17 = 25X5.7R17
155/70R17 = 25.5X6.1R17
205/50R17 = 25.1x8.1R17
205/55R17 = 25.9x8.1R17
215/50R17 = 25.5X8.5R17
225/45R17 = 25x8.9R17
225/50R17 = 25.9x8.9R17
235/45R17 = 25.3x9.3R17
245/45R17 = 25.7x9.6R17
255/40R17 = 25x10R17
265/40R17 = 25.3x10. 4R17
275/40R17 = 25.7x10.8R17
295/35R17 = 25.1x11.6R17
315/35R17 = 25.7x12.4R17

26" Tire Diameter
135/90R17 = 26.6X5.3R17
145/80R17 = 26.1X5.7R17
155/80R17 = 26.8X6.1R17
215/55R17 = 26.3x8.5R17
225/55R17 = 26.7x8.9R17
235/50R17 = 26.3x9.3R17
245/50R17 = 26.6x9.6R17
255/45R17 = 26x10R17
26X11.5R17
285/40R17 = 26x11.2R17
295/40R17 = 26.3x11.6R17
335/35R17 = 26.2x13.2R17

27" Tire Diameter
145/90R17 = 27.3X5.7R17
165/80R17 = 27.4X6.5R17
215/60R17 = 27.2x8.5R17
225/60R17 = 27.6x8.9R17
235/55R17 = 27.2x9.3R17
245/55R17 = 27.6x9.6R17
255/50R17 = 27x10R17
275/50R17 = 27.8X10.8R17
305/45R17 = 27.8X12R17
345/40R17 = 27.9x13.6R17

28" Tire Diameter
155/90R17 = 28X6.1R17
165/90R17 = 28.7X6.5R17
215/65R17 = 28x8.5R17
215/70R17 = 28.9x8.5R17
225/65R17 = 28.5x8.9R17
235/60R17 = 28.1x9.3R17
245/60R17 = 28.6X9.6R17
255/55R17 = 28x10R17
275/55R17 = 28. 9x10.8R17

29" Tire Diameter
175/90R17 = 29.4X6.9R17
225/70R17 = 29.4x8.9R17
235/65R17 = 29x9.3R17
245/65R17 = 29.5x9.6R17
255/60R17 = 29x10R17
265/60R17 = 29.5x10.4R17

30" Tire Diameter
225/75R17 = 30.3x8.9R17
235/70R17 = 30x9.3R17
235/75R17 = 30.9x9.3R17
245/70R17 = 30.5x9.6R17
255/65R17 = 30.1x10R17
265/65R17 = 30.6x10.4R17
275/60R17 = 30x10.8R17
285/60R17 = 30.5X11.2R17

31" Tire Diameter
235/80R17 = 31.8x9.3R17
245/75R17 = 31.5x9.6R17
255/70R17 = 31.1x10R17
265/70R17 = 31.6x10.4R17
275/65R17 = 31.1x10.8R17
285/65R17 = 31.6x11.2R17
31X10.5R17

32" Tire Diameter
235/85R17 = 32.7X9.3R17
255/75R17 = 32.1x10R17
275/70R17 = 32.2x10.8R17
285/70R17 = 32.7x11.2R17
305/65R17 = 32.6x12R17
32X10.5R17
32X11.5R17

33" Tire Diameter
255/80R17 = 33.1x10R17
285/75R17 = 33.8x11.2R17
295/70R17 = 33.3x11. 6R17
305/70R17 = 33.8x12R17
33X10.5R17
33X12.5R17
33X13R17
33X13.5R17
33X9.5R17

34" Tire Diameter
275/80R17 = 34.3X10.8R17
315/70R17 = 34.4x12.4R17
325/70R17 = 34.9x12.8R17
34X10.5R17

35" Tire Diameter
35X10.5R17
35X11.5R17
35X12.5R17
35X13.5R17
35X14.5R17

36" Tire Diameter
355/70R17 = 36.6x14R17
36X12.5R17
36X13.5R17

37" Tire Diameter
37X12.5R17
37X13R17
37X13.5R17
37X14R17

38" Tire Diameter
38X13.5R17
38X14.5R17
38X15.5R17
38.5X13.5R17
38.5X14.5R17

39" Tire Diameter
39X13.5R17
39.5X13.5R17
39.5X15R17

40" Tire Diameter
40X13.5R17
40X14.5R17
40X16R17

41" Tire Diameter
41X14.5R17

42" Tire Diameter
42X14R17
42X14.5R17
42X15R17
42.5X13.5R17

43" Tire Diameter
43X14.5R17

44" Tire Diameter
44X19. 5R17
44X21R17

47" Tire Diameter
47X17R17

49" Tire Diameter
49X21R17

54" Tire Diameter
54X19.5R17

Tire Size Calculator Chart for 18" Wheels

23" Tire Diameter
215/35R18 = 23.9x8.5R18

24" Tire Diameter
125/70R18 = 24.9X4.9R18
205/40R18 = 24.5x8.1R18
215/40R18 = 24.8x8.5R18
225/35R18 = 24.2x8.9R18
235/35R18 = 24.5x9.3R18
245/35R18 = 24.8x9.6R18
285/30R18 = 24.7x11.2R18

25" Tire Diameter
135/70R18 = 25.4X5.3R18
155/60R18 = 25.3X6.1R18
215/45R18 = 25.6x8.5R18
225/40R18 = 25.1x8.9R18
235/40R18 = 25.4x9.3R18
245/40R18 = 25.7x9.6R18
255/35R18 = 25x10R18
265/35R18 = 25.3x10.4R18
275/35R18 = 25.6x10.8R18
285/35R18 = 25.9x11.2R18
295/30R18 = 25x11.6R18
305/30R18 = 25.2x12R18
315/30R18 = 25.4x12.4R18
335/30R18 = 25.9x13.2R18

26" Tire Diameter
135/80R18 = 26.5X5.3R18
145/70R18 = 26X5. 7R18
215/50R18 = 26.5X8.5R18
225/45R18 = 26x8.9R18
225/50R18 = 26.9x8.9R18
235/45R18 = 26.3x9.3R18
245/45R18 = 26.7x9.6R18
255/40R18 = 26x10R18
26X12R18
265/40R18 = 26.3x10.4R18
275/40R18 = 26.7x10.8R18
295/35R18 = 26.1x11.6R18
305/35R18 = 26.4x12R18
315/35R18 = 26.7x12.4R18
345/30R18 = 26.1x13.6R18

27" Tire Diameter
145/80R18 = 27.1X5.7R18
145/85R18 = 27.7X5.7R18
215/55R18 = 27.3x8.5R18
225/55R18 = 27.7x8.9R18
235/50R18 = 27.3x9.3R18
245/50R18 = 27.6x9.6R18
255/45R18 = 27x10R18
265/45R18 = 27.4x10.4R18
275/45R18 = 27.7x10.8R18
285/40R18 = 27x11.2R18
295/40R18 = 27.3x11.6R18
305/40R18 = 27.6X12R18
315/40R18 = 27.9x12.4R18
325/35R18 = 27x12.8R18
345/35R18 = 27.5x13.6R18

28" Tire Diameter
155/85R18 = 28.4X6.1R18
225/60R18 = 28.6x8.9R18
235/55R18 = 28.2x9.3R18
245/55R18 = 28.6x9.6R18
255/50R18 = 28x10R18
265/50R18 = 28.4X10. 4R18
285/45R18 = 28.1x11.2R18
295/45R18 = 28.5x11.6R18
305/45R18 = 28.8X12R18

29" Tire Diameter
155/90R18 = 29X6.1R18
165/90R18 = 29.7X6.5R18
225/65R18 = 29.5X8.9R18
235/60R18 = 29.1x9.3R18
245/60R18 = 29.6x9.6R18
255/55R18 = 29x10R18
265/55R18 = 29.5X10.4R18
275/55R18 = 29.9x10.8R18
285/50R18 = 29.2x11.2R18
325/45R18 = 29.5X12.8R18

30" Tire Diameter
175/90R18 = 30.4X6.9R18
235/65R18 = 30x9.3R18
245/65R18 = 30.5x9.6R18
255/60R18 = 30x10R18
265/60R18 = 30.5x10.4R18
285/55R18 = 30.3x11.2R18

31" Tire Diameter
235/70R18 = 31X9.3R18
255/65R18 = 31.1x10R18
265/65R18 = 31.6x10.4R18
275/60R18 = 31x10.8R18
285/60R18 = 31.5x11.2R18

32" Tire Diameter
255/70R18 = 32.1x10R18
265/70R18 = 32.6x10.4R18
275/65R18 = 32.1x10.8R18
285/65R18 = 32.6x11.2R18
305/60R18 = 32.4x12R18

33" Tire Diameter
275/70R18 = 33. 2x10.8R18
285/70R18 = 33.7x11.2R18
295/65R18 = 33.1x11.6R18
305/65R18 = 33.6x12R18
325/60R18 = 33.4x12.8R18
33X10.5R18
33X11.5R18
33X12.5R18
33X13R18
33X13.5R18

34" Tire Diameter
285/75R18 = 34.8x11.2R18
295/70R18 = 34.3X11.6R18
305/70R18 = 34.8x12R18
325/65R18 = 34.6x12.8R18
34X12.5R18

35" Tire Diameter
315/70R18 = 35.4x12.4R18
35X11.5R18
35X12.5R18
35X13R18
35X13.5R18
35X14.5R18

36" Tire Diameter
355/65R18 = 36.2x14R18
36X13.5R18

37" Tire Diameter
37X11.5R18
37X12.5R18
37X13.5R18

38" Tire Diameter
38X13.5R18
38X14.5R18
38X15R18
38X15.5R18
38.5X14.5R18

40" Tire Diameter
40X13.5R18
40X14.5R18

41" Tire Diameter
41X14.5R18

Tire Size Calculator Chart for 19" Wheels

24" Tire Diameter
215/35R19 = 24.9x8.5R19
235/30R19 = 24. 6x9.3R19
245/30R19 = 24.8x9.6R19
295/25R19 = 24.8X11.6R19

25" Tire Diameter
115/70R19 = 25.3X4.5R19
125/70R19 = 25.9X4.9R19
225/35R19 = 25.2x8.9R19
235/35R19 = 25.5x9.3R19
245/35R19 = 25.8x9.6R19
255/30R19 = 25x10R19
265/30R19 = 25.3x10.4R19
275/30R19 = 25.5x10.8R19
285/30R19 = 25.7x11.2R19
315/25R19 = 25.2x12.4R19

26" Tire Diameter
135/70R19 = 26.4X5.3R19
225/40R19 = 26.1x8.9R19
235/40R19 = 26.4x9.3R19
245/40R19 = 26.7x9.6R19
255/35R19 = 26x10R19
265/35R19 = 26.3x10.4R19
275/35R19 = 26.6x10.8R19
285/35R19 = 26.9x11.2R19
295/30R19 = 26x11.6R19
305/30R19 = 26.2x12R19
315/30R19 = 26.4x12.4R19
325/30R19 = 26.7x12.8R19
335/30R19 = 26.9x13.2R19

27" Tire Diameter
155/70R19 = 27.5x6.1R19
175/60R19 = 27.3x6.9R19
225/45R19 = 27x8.9R19
235/45R19 = 27.3x9.3R19
245/45R19 = 27.7x9.6R19
255/40R19 = 27x10R19
265/40R19 = 27.3x10. 4R19
275/40R19 = 27.7x10.8R19
295/35R19 = 27.1x11.6R19
305/35R19 = 27.4X12R19
315/35R19 = 27.7x12.4R19
345/30R19 = 27.1x13.6R19
355/30R19 = 27.4x14R19

28" Tire Diameter
145/80R19 = 28.1X5.7R19
155/80R19 = 28.8X6.1R19
225/55R19 = 28.7x8.9R19
235/50R19 = 28.3x9.3R19
245/50R19 = 28.6x9.6R19
255/45R19 = 28x10R19
265/45R19 = 28.4X10.4R19
275/45R19 = 28.7x10.8R19
285/40R19 = 28x11.2R19
295/40R19 = 28.3X11.6R19
315/40R19 = 28.9x12.4R19
345/35R19 = 28.5x13.6R19

29" Tire Diameter
235/55R19 = 29.2x9.3R19
245/55R19 = 29.6x9.6R19
255/50R19 = 29x10R19
265/50R19 = 29.4x10.4R19
275/50R19 = 29.8X10.8R19
285/45R19 = 29.1x11.2R19
295/45R19 = 29.5x11.6R19

30" Tire Diameter
165/90R19 = 30.7X6.5R19
175/80R19 = 30X6.9R19
255/55R19 = 30x10R19
265/55R19 = 30.5x10.4R19
275/55R19 = 30.9x10.8R19

31" Tire Diameter
235/65R19 = 31X9. 3R19
255/60R19 = 31x10R19

Tire Size Calculator Chart for 20" Wheels

25" Tire Diameter
215/30R20 = 25.1X8.5R20
225/30R20 = 25.3x8.9R20
235/30R20 = 25.6x9.3R20
245/30R20 = 25.8x9.6R20
275/25R20 = 25.4X10.8R20
285/25R20 = 25.6x11.2R20
295/25R20 = 25.8x11.6R20

26" Tire Diameter
145/60R20 = 26.9X5.7R20
225/35R20 = 26.2x8.9R20
235/35R20 = 26.5x9.3R20
245/35R20 = 26.8x9.6R20
255/30R20 = 26x10R20
265/30R20 = 26.3x10.4R20
275/30R20 = 26.5x10.8R20
285/30R20 = 26.7x11.2R20
305/25R20 = 26x12R20
315/25R20 = 26.2x12.4R20
325/25R20 = 26.4x12.8R20
335/25R20 = 26.6x13.2R20
345/25R20 = 26.8X13.6R20

27" Tire Diameter
155/60R20 = 27.3x6.1R20
155/65R20 = 27.9X6.1R20
165/60R20 = 27.8X6.5R20
175/55R20 = 27.6x6.9R20
195/50R20 = 27.7x7.7R20
215/45R20 = 27.6x8.5R20
225/40R20 = 27.1X8.9R20
235/40R20 = 27.4x9.3R20
245/40R20 = 27.7x9.6R20
255/35R20 = 27x10R20
265/35R20 = 27. 3x10.4R20
275/35R20 = 27.6x10.8R20
285/35R20 = 27.9x11.2R20
295/30R20 = 27x11.6R20
305/30R20 = 27.2x12R20
315/30R20 = 27.4x12.4R20
325/30R20 = 27.7x12.8R20
335/30R20 = 27.9x13.2R20

28" Tire Diameter
225/45R20 = 28X8.9R20
235/45R20 = 28.3x9.3R20
245/45R20 = 28.7x9.6R20
255/40R20 = 28x10R20
265/40R20 = 28.3x10.4R20
275/40R20 = 28.7x10.8R20
295/35R20 = 28.1x11.6R20
305/35R20 = 28.4x12R20
315/35R20 = 28.7x12.4R20
345/30R20 = 28.1x13.6R20

29" Tire Diameter
235/50R20 = 29.3X9.3R20
245/50R20 = 29.6x9.6R20
255/45R20 = 29x10R20
265/45R20 = 29.4x10.4R20
275/45R20 = 29.7x10.8R20
285/40R20 = 29x11.2R20
295/40R20 = 29.3x11.6R20
305/40R20 = 29.6X12R20
325/35R20 = 29X12.8R20

30" Tire Diameter
235/55R20 = 30.2x9.3R20
255/50R20 = 30x10R20
265/50R20 = 30.4x10.4R20
275/50R20 = 30.8x10.8R20
285/45R20 = 30.1X11.2R20
295/45R20 = 30.5x11. 6R20
305/45R20 = 30.8x12R20

31" Tire Diameter
245/60R20 = 31.6x9.6R20
255/55R20 = 31x10R20
275/55R20 = 31.9x10.8R20
285/50R20 = 31.2x11.2R20
295/50R20 = 31.6x11.6R20
31X18R20

32" Tire Diameter
265/60R20 = 32.5x10.4R20
285/55R20 = 32.3x11.2R20
295/55R20 = 32.8X11.6R20
305/50R20 = 32x12R20
315/50R20 = 32.4x12.4R20
325/50R20 = 32.8x12.8R20

33" Tire Diameter
275/60R20 = 33x10.8R20
285/60R20 = 33.5x11.2R20
295/60R20 = 33.9X11.6R20
305/55R20 = 33.2x12R20
33X11.5R20
33X12R20
33X12.5R20
33X13.5R20

34" Tire Diameter
275/65R20 = 34.1x10.8R20
285/65R20 = 34.6x11.2R20
305/60R20 = 34.4x12R20
315/60R20 = 34.9x12.4R20
355/50R20 = 34X14R20

35" Tire Diameter
295/65R20 = 35.1X11.6R20
325/60R20 = 35.4x12.8R20
35X11.5R20
35X12.5R20
35X13R20
35X13.5R20
35X14.5R20

36" Tire Diameter
355/60R20 = 36. 8x14R20
36X13.5R20
36X15.5R20

37" Tire Diameter
37X11.5R20
37X12.5R20
37X13.5R20
37X14.5R20

38" Tire Diameter
38X13.5R20
38X14.5R20
38X15.5R20
38.5X13.5R20
38.5X14.5R20

39" Tire Diameter
39X13.5R20
39.5X13.5R20
39.5X15R20

40" Tire Diameter
40X13.5R20
40X14.5R20
40X15.5R20

41" Tire Diameter
41X14.5R20

42" Tire Diameter
42X14.5R20
42X15R20
42.5X13.5R20

43" Tire Diameter
43X14.5R20

44" Tire Diameter
44X19.5R20
44X19.5R20
44X21R20

45" Tire Diameter
45X14.5R20

46" Tire Diameter
46X19.5R20

49" Tire Diameter
49X21R20

54" Tire Diameter
54X19.5R20

Tire Size Calculator Chart for 21" Wheels

26" Tire Diameter
245/30R21 = 26.8x9.6R21
295/25R21 = 26.8x11.6R21

27" Tire Diameter
245/35R21 = 27. 8x9.6R21
255/30R21 = 27x10R21
265/30R21 = 27.3x10.4R21
275/30R21 = 27.5x10.8R21
285/30R21 = 27.7x11.2R21
305/25R21 = 27x12R21
325/25R21 = 27.4x12.8R21

28" Tire Diameter
245/40R21 = 28.7x9.6R21
255/35R21 = 28X10R21
265/35R21 = 28.3x10.4R21
275/35R21 = 28.6x10.8R21
285/35R21 = 28.9x11.2R21
295/30R21 = 28x11.6R21
305/30R21 = 28.2x12R21
315/30R21 = 28.4X12.4R21
325/30R21 = 28.7x12.8R21
355/25R21 = 28x14R21

29" Tire Diameter
245/45R21 = 29.7X9.6R21
255/40R21 = 29X10R21
265/40R21 = 29.3x10.4R21
275/40R21 = 29.7x10.8R21
295/35R21 = 29.1x11.6R21
305/35R21 = 29.4X12R21
315/35R21 = 29.7X12.4R21

30" Tire Diameter
265/45R21 = 30.4x10.4R21
275/45R21 = 30.7x10.8R21
285/40R21 = 30X11.2R21
295/40R21 = 30.3x11.6R21
315/40R21 = 30.9X12.4R21

31" Tire Diameter
255/50R21 = 31x10R21
275/50R21 = 31.8X10.8R21
285/45R21 = 31.1x11. 2R21
325/40R21 = 31.2X12.8R21

Tire Size Calculator Chart for 22" Wheels

27" Tire Diameter
235/30R22 = 27.6x9.3R22
245/30R22 = 27.8x9.6R22
275/25R22 = 27.4x10.8R22
285/25R22 = 27.6x11.2R22
295/25R22 = 27.8x11.6R22

28" Tire Diameter
255/30R22 = 28x10R22
265/30R22 = 28.3x10.4R22
275/30R22 = 28.5X10.8R22
285/30R22 = 28.7x11.2R22
305/25R22 = 28x12R22
315/25R22 = 28.2x12.4R22
335/25R22 = 28.6x13.2R22

29" Tire Diameter
255/35R22 = 29x10R22
265/35R22 = 29.3x10.4R22
275/35R22 = 29.6X10.8R22
285/35R22 = 29.9x11.2R22
295/30R22 = 29x11.6R22
305/30R22 = 29.2x12R22
315/30R22 = 29.4X12.4R22

30" Tire Diameter
255/40R22 = 30X10R22
265/40R22 = 30.3x10.4R22
275/40R22 = 30.7x10.8R22
295/35R22 = 30.1X11.6R22
305/35R22 = 30.4X12R22
315/35R22 = 30.7X12.4R22

31" Tire Diameter
255/45R22 = 31X10R22
265/45R22 = 31.4X10. 4R22
275/45R22 = 31.7x10.8R22
285/40R22 = 31x11.2R22
295/40R22 = 31.3x11.6R22
305/40R22 = 31.6x12R22
325/35R22 = 31X12.8R22

32" Tire Diameter
275/50R22 = 32.8x10.8R22
285/45R22 = 32.1x11.2R22
305/45R22 = 32.8x12R22

33" Tire Diameter
285/50R22 = 33.2x11.2R22
33X12.5R22
33X14.5R22
355/40R22 = 33.2X14R22

34" Tire Diameter
285/55R22 = 34.3X11.2R22
295/55R22 = 34.8X11.6R22
305/50R22 = 34x12R22
325/50R22 = 34.8x12.8R22

35" Tire Diameter
35X12.5R22
35X14.5R22
35X15.5R22
375/45R22 = 35.3X14.8R22

36" Tire Diameter
325/55R22 = 36.1x12.8R22
335/55R22 = 36.5X13.2R22

37" Tire Diameter
325/60R22 = 37.4x12.8R22
37X12.5R22
37X13.5R22

38" Tire Diameter
355/60R22 = 38.8x14R22
38X13.5R22
38X15.5R22

40" Tire Diameter
40X14.5R22
40X15.5R22

41" Tire Diameter
41X14. 5R22

42" Tire Diameter
42.5X13.5R22

Tire Size Calculator Chart for 23" Wheels

28" Tire Diameter
265/25R23 = 28.2X10.4R23

30" Tire Diameter
285/35R23 = 30.9x11.2R23
325/30R23 = 30.7X12.8R23

31" Tire Diameter
275/40R23 = 31.7X10.8R23

32" Tire Diameter
285/40R23 = 32x11.2R23
305/40R23 = 32.6x12R23
325/35R23 = 32X12.8R23

Tire Size Calculator Chart for 24" Wheels

29" Tire Diameter
275/25R24 = 29.4x10.8R24

30" Tire Diameter
255/30R24 = 30x10R24
275/30R24 = 30.5x10.8R24
285/30R24 = 30.7x11.2R24

31" Tire Diameter
285/35R24 = 31.9x11.2R24
295/30R24 = 31X11.6R24

32" Tire Diameter
295/35R24 = 32.1x11.6R24
305/35R24 = 32.4x12R24
315/35R24 = 32.7x12.4R24
405/25R24 = 32x15.9R24

33" Tire Diameter
285/40R24 = 33x11.2R24
295/40R24 = 33.3x11.6R24

34" Tire Diameter
385/35R24 = 34. 6x15.2R24

35" Tire Diameter
325/45R24 = 35.5x12.8R24
35X12.5R24
35X13.5R24
375/40R24 = 35.8X14.8R24

36" Tire Diameter
315/50R24 = 36.4X12.4R24

37" Tire Diameter
37X13.5R24
37X14.5R24

38" Tire Diameter
38X13.5R24
38X14R24
38X15.5R24

40" Tire Diameter
40X13.5R24
40X14.5R24
40X15.5R24

42" Tire Diameter
42X15.5R24

Tire Size Calculator Chart for 26" Wheels

31" Tire Diameter
275/25R26 = 31.4x10.8R26
295/25R26 = 31.8x11.6R26

33" Tire Diameter
295/30R26 = 33x11.6R26
305/30R26 = 33.2x12R26

35" Tire Diameter
315/40R26 = 35.9x12.4R26

37" Tire Diameter
37X13.5R26

38" Tire Diameter
38X15.5R26

40" Tire Diameter
40X13.5R26
40X15.5R26

42" Tire Diameter
42X15.5R26

Tire Size Calculator Chart for 28" Wheels

33" Tire Diameter
295/25R28 = 33. 8x11.6R28

37" Tire Diameter
325/35R28 = 37x12.8R28

40" Tire Diameter
40X15.5R28

42" Tire Diameter
42X15.5R28

Tire Size Calculator Chart for 30" Wheels

37" Tire Diameter
315/30R30 = 37.4x12.4R30

How to determine the diameter of the wheel

Heading: Tips for a car enthusiast

First of all, we find the exact size of the wheel diameter, and then we go to buy the appropriate tires. How correctly you do this, how correctly and steadily your car will behave on the road. The diameter of the wheel is a composite value, which is why care is required in the calculations. How to determine the diameter of the wheel is our topic today.

Determining the diameter and choosing the right tires!

How to determine the diameter of a wheel

Step-by-step instructions on how to determine the diameter of a wheel

How to determine the diameter of a wheel

Step 1. The simplest formula is used for calculations: it is necessary to add the sum of two tire profile heights to the diameter of the wheel. This method is applicable only when calculating for passenger cars.

Step 2. Take a tape measure for the usual way of measuring the diameter of the wheel. Each parameter taken from the formula must be measured separately. The values ​​​​that you get must be converted to inches (since the unit of measurement for the diameter of a car wheel is an inch). We translate into inches as follows: divide each number obtained by 2.54. Then you need to add together the values ​​obtained as a result of the measurement. The resulting number is the diameter of your wheel.

Step 3. You don't have to do mathematical calculations, just apply an even simpler calculation formula. How to determine the diameter of the wheel using the second formula - you need to take the number that indicates the width of the rim, and add 20% to it, so you get the full width of your wheel. If the tire width is narrow, then the difference between the total width of the wheels and the width of the rim will be 15%.

Step 4. Experts do not recommend making the wheel diameter larger than the allowable limits. The permissible norm is to increase the diameter of the wheel by a maximum of several centimeters. A wheel size that exceeds the allowable values ​​will have a bad effect on the chassis of the car, as well as touch the wheel arches. It will be necessary to change the alignment of the car, which will then affect fuel consumption.

Step 5. When maximizing the diameter of the rim, choose an appropriately low profile tire compared to the standard tyre. Do not forget that low-profile tires do not have the same margin of safety as a standard tire. It is necessary to maintain a balance between the overall diameter of the wheel and disk. Plus, low-profile tires, along with the maximum diameter of the disk, deprives you of the usual comfort, and also affects the chassis.

Step 6. Wheel rim diameter is an important part of a car wheel. You need to know and remember that wheel parameters in terms of rim diameter can range from 10 to 23 inches. The parameters of small indicators refer to motorcycles and mopeds. Large indicators are used among powerful vehicles.

Useful tips for car owners.

If you have doubts about your calculations, you can always turn to specialists. How to determine the diameter of the wheel - experienced specialists at a glance can give you accurate information on your wheels. To do this, you can drive to any auto service or car service station. There you will receive the exact information you are interested in.

We told you how to determine the diameter of the wheel, try it!

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How to choose and measure the wheel diameter

Valery Leonidov

31 August 2017 11:21

A large number of manufacturers, shapes, sizes, patterns and other indicators of car tires are shocking for an inexperienced car owner. The right choice is the key not only to a long service life of the wheels, but also to safety while driving, since the appropriately selected rubber tread is responsible for the car's grip on the road. For the right choice, you need to take into account some subtleties, determine the priority characteristics that rubber should have.

Today there are a lot of options to get the necessary information. For example, you can consult online, on the site, but in any case you should know what to ask. If you are changing tires or rims from smaller to larger and vice versa, you need to know a thing or two about sizing and other intricacies of selection. As a rule, cars are produced with factory wheels, which are somewhat smaller than we might like. Such a replacement carries more aesthetic meaning, but it still has practicality.

Larger wheels up to 18 inches have a positive effect on cornering, traction, braking performance, ride comfort and steering feel, while negatively affecting acceleration and fuel economy due to the greater weight of the wheels themselves. In 19 inches and up, tests have shown that the positive improvements have disappeared, and acceleration and fuel economy have deteriorated. So the large diameter of the wheels and tires, apart from beauty, does not carry anything in itself. Car owners usually set a smaller radius if they have a second set of tires, such as winter tires that they install every winter. Winter tires tend to get a lot more expensive at sizes over 17 inches. In addition, the wider the tire, the more effective it is on snow and ice.

So if you have 18" or 19" wheels and want an extra set of wheels for winter tires, it's a good idea to go down to 17" or 16" wheels. These diameters are not only cheaper, easier to find, but also have better grip than other sizes.

Speedometer, odometer, traction control, torque and gear settings are based on the distance your tire travels in one full revolution, which is determined by the outside diameter of the tire and wheel combined. A tire with a different outer diameter will travel a different distance compared to one revolution with different torque. When changing the diameter of your rims, you must make sure that the new wheels in the assembly have the same overall diameter as the old one or your speedometer, otherwise the readings of these gauges will not be correct.

How to read the numbers on tires


Tires have 3 digits, eg 225/55/16. For a tire of this size, the first number (225) indicates the width of the tire in millimeters. The second digit (55) represents the ratio of width to height; that is, the aspect ratio is 55 percent of the width, or 123.75 mm. The end number (16) refers to the inner diameter.

The outer diameter of a tire is its height. To keep the same outer diameter, you need to take a smaller tire height with large rims and vice versa. It takes a bit of math to figure out the right size.

To get the standing height of the tire, multiply the aspect height by two for the top and bottom sidewalls and add the 16-inch inner diameter of the tire.

After converting from millimeters to inches, this gives a height of about 25.


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