Understanding your vehicle’s tire size is crucial for its performance and safety. The tire size, often found on the sidewall of your tire, is a series of numbers and letters that hold significant information about your tire’s specifications. This guide will help you know what these numbers mean and how to choose the right tire size for your vehicle.

Tire sizes are typically represented in the Width/Aspect Ratio R Rim Diameter format. The width and aspect ratio can calculate the tire’s sidewall height. The aspect ratio is a percentage. So, for a tire size 205 50r17, the sidewall height would be 50% of 205 mm, and the rim size would be 17.

Calculating Tire Sizes

Tire Size List And All You Need To Know About Wheel

Section Width: This is the width of the tire, measured in millimeters. It is the first number in the tire size marking.

Aspect Ratio: A tire’s aspect ratio refers to the height of the tire’s section divided by its width. It is the second number in the tire size marking.

Sidewall Height: The distance from the edge of the tire to the wheel is known as sidewall height. It is calculated by multiplying the tire’s width by the aspect ratio.

Tire Diameter: This is the distance from one side of the tire to the other. It is calculated by multiplying the sidewall by two and adding the rim diameter.

Tire Circumference: The tire circumference is the measurement of the distance around the outer edge of the tire.

We’ve sorted the tires based on their rim sizes first, then by the calculated sidewall height.

Tire Size list 13 To 17 Rim Size:

Rim Size	Tire Size	Width (mm)	Aspect Ratio (%)	Sidewall Height (mm)
13	145/70 R13	145	70	101.5
13	155/70 R13	155	70	108.5
13	165/70 R13	165	70	115.5
13	175/65 R13	175	65	113.75
13	175/70 R13	175	70	122.5
13	185/70 R13	185	70	129.5
14	155/65 R14	155	65	100.75
14	165/60 R14	165	60	99
14	165/65 R14	165	65	107.25
14	165/70 R14	165	70	115.5
14	175/65 R14	175	65	113.75
14	185/60 R14	185	60	111
14	175/70 R14	175	70	122.5
14	185/65 R14	185	65	120.25
14	195/60 R14	195	60	117
14	195/65 R14	195	65	126.75
14	175/80 R14	175	80	140
14	185/70 R14	185	70	129.5
15	185/55 R15	185	55	101.75
15	185/60 R15	185	60	111
15	195/50 R15	195	50	97.5
15	195/55 R15	195	55	107.25
15	185/65 R15	185	65	120.25
15	195/60 R15	195	60	117
15	205/60 R15	205	60	123
15	195/65 R15	195	65	126.75
15	205/65 R15	205	65	133.25
15	195/70 R15	195	70	136.5
15	205/70 R15	205	70	143.5
15	215/70 R15	215	70	150.5
15	225/70 R15	225	70	157.5
15	215/75 R15	215	75	161.25
15	225/75 R15	225	75	168.75
15	235/75 R15	235	75	176.25
15	255/75 R15	255	75	191.25
15	265/70 R15	265	70	185.5
16	195/45 R16	195	45	87.75
16	205/55 R16	205	55	112.75
16	195/55 R16	195	55	107.25
16	215/40 R16	215	40	86
16	215/45 R16	215	45	96.75
16	205/50 R16	205	50	102.5
16	215/55 R16	215	55	118.25
16	225/55 R16	225	55	123.75
16	215/65 R16	215	65	139.75
16	205/60 R16	205	60	123
16	215/60 R16	215	60	129
16	235/70 R16	235	70	164.5
16	225/70 R16	225	70	157.5
16	245/70 R16	245	70	171.5
16	255/70 R16	255	70	178.5
16	265/70 R16	265	70	185.5
17	205/40 R17	205	40	82
17	205/45 R17	205	45	92.25
17	215/40 R17	215	40	86
17	215/45 R17	215	45	96.75
17	225/45 R17	225	45	101.25
17	235/45 R17	235	45	105.75
17	245/40 R17	245	40	98
17	245/45 R17	245	45	110.25
17	205/50 R17	205	50	102.5
17	205/55 R17	205	55	112.75
17	215/50 R17	215	50	107.5
17	215/55 R17	215	55	118.25
17	225/50 R17	225	50	112.5
17	225/55 R17	225	55	123.75
17	235/55 R17	235	55	129.25
17	245/ 45 R17	245	45	110.25
17	235/ 65 R17	235	65	152.75
17	225/ 65 R17	225	65	146.25
17	255/ 60 R17	255	60	153
17	225/ 60 R17	225	60	135
17	215/ 60 R17	215	60	129
17	215/ 65 R17	215	65	139.75
17	265/ 70 R17	265	70	185.5

Tire Size list 18 To 21 Rim Size:

Rim Size	Tire Size	Width (mm)	Aspect Ratio (%)	Sidewall Height (mm)
18	225/40 R18	225	40	90
18	225/45 R18	225	45	101.25
18	235/40 R18	235	40	94
18	235/45 R18	235	45	105.75
18	245/40 R18	245	40	98
18	245/45 R18	245	45	110.25
18	255/45 R18	255	45	114.75
18	255/55 R18	255	55	140.25
18	235/55 R18	235	55	129.25
18	255/60 R18	255	60	153
18	265/60 R18	265	60	159
19	225/40 R19	225	40	90
19	235/55 R19	235	55	129.25
19	245/40 R19	245	40	98
19	245/45 R19	245	45	110.25
19	255/45 R19	255	45	114.75
19	245/50 R19	245	50	122.5
19	255/50 R19	255	50	127.5
19	255/55 R19	255	55	140.25
20	245/40 R20	245	40	98
20	245/45 R20	245	45	110.25
20	255/50 R20	255	50	127.5
20	255/55 R20	255	55	140.25
20	265/45 R20	265	45	119.25
20	275/40 R20	275	40	110
20	275/45 R20	275	45	123.75
20	265/50 R20	265	50	132.5
21	295/35 R21	295	35	103.25
21	285/40 R21	285	40	114
21	295/40 R21	295	40	118

If you are a used tire wholesaler, you might be interested in our Used Tire Price Calculator for the German Market.

Difference between R and C in tire sizes

Regarding tire sizes, the letters ‘R’ and ‘C’ play a significant role. ‘R’ stands for Radial construction, typical in passenger cars and light truck tires. Radial construction means the tire’s internal ply cords are oriented in a radial direction, from one bead to the other, providing excellent strength and flexibility and helping create a comfortable ride.

On the other hand, ‘C’ usually indicates ‘Commercial.’ Tires marked with a ‘C’ are designed for commercial vehicles or vans that require higher load-bearing capacities. These tires are built to withstand the heavy demands of commercial use.

Choosing the right tire size for your car

Choosing the right tire size for your car is essential for safety, performance, and fuel efficiency. You can find the tire size on the sidewall of your current tires, inside your car’s door jamb, or in the car’s manual. The replacement tires should match the manufacturer’s size, load index, and speed rating recommendations to ensure optimal performance and safety.

Reading a tire sidewall

The sidewall of a tire contains a wealth of information. It includes the tire type, width, aspect ratio, construction type (e.g., radial), rim diameter, load index, and speed rating. For example, a tire size of 225/50R17 means the tire has a section width of 225mm, an aspect ratio of 50%, is of Radial construction, and fits a 17-inch rim.

Difference between aspect ratio and section width

The aspect ratio and section width are two critical measurements on a tire. The aspect ratio is the sidewall height as a percentage of the section width. For instance, if a tire has an aspect ratio of 50, the height is 50% of the width.

On the other hand, the section width is the measurement from the inner to the outer sidewall, excluding any protective ribs, decorations, or raised letters. It’s the linear distance across the tire cross-section.

Knowing if your car needs commercial tires

Commercial tires are designed for vehicles or vans requiring higher load-bearing capacities. If you’re unsure whether your car needs commercial tires, refer to the vehicle’s manual or consult a tire professional. They can provide guidance based on your vehicle’s specifications and usage.

Measuring tire pressure

Measuring tire pressure is a simple process that can be done with a tire pressure gauge. First, remove the valve cap from your tire. Then, press the gauge onto the valve stem until the hissing sound stops. This indicates that air has stopped escaping from the tire. The reading on the indicator shows your tire’s pressure. Compare this reading to the recommended pressure in your vehicle’s manual or on a sticker inside the driver’s door.

Difference between summer and winter tires

Tires are designed differently based on the seasons they are intended for. Summer tires are firmer, have fewer grooves, and are suitable for temperatures above +7°C. They offer excellent performance in wet and dry conditions and provide optimal grip on warm roads.

Winter tires, on the other hand, have a higher natural rubber content and more grooves. They remain flexible in cold temperatures, offering better grip and traction in snowy or icy conditions. Winter tires are ideal for temperatures below +7°C.

Knowing when to replace your tires

Tire replacement is necessary when the tread depth is below 2/32nds of an inch or if the tires are over six years old, regardless of tread depth. Regularly inspect your tires for wear and damage to ensure your safety on the road.

Checking tire pressure

Checking tire pressure is similar to measuring it. First, remove the valve cap from your tire. Then, press the gauge onto the valve stem until the hissing sound stops. This indicates that air has stopped escaping from the tire. The reading on the indicator shows your tire’s pressure. Compare this reading to the recommended pressure in your vehicle’s manual or on a sticker inside the driver’s door.

Difference between R and ZR in tire speed ratings

The letters ‘R’ and ‘ZR’ in tire sizes refer to different aspects. ‘R’ denotes Radial construction, typical in passenger cars and light truck tires. On the other hand, ‘ZR’ indicates a tire has high-speed capability. Tires with a ‘ZR’ rating are designed to handle speeds above 240 km/h.

Knowing if your tires are correctly inflated

Proper tire inflation is crucial for optimal performance and safety. To know if your tires are correctly inflated, measure the pressure with a gauge and compare it to the recommended pressure. The recommended pressure is usually found in your vehicle’s manual or a sticker inside the driver’s door.

Rotating tires

Rotating tires involves changing the positions of your vehicle’s tires to promote even wear. The specific pattern for rotating tires depends on the vehicle type, tire wear patterns, and the type of tires (directional/non-directional). Regular tire rotation can extend the life of your tires and improve your vehicle’s performance.

Choosing a tire size for your car

About rim sizes

Rim size refers to the diameter of the tire’s bead seating area, measured in inches. It’s an essential factor when choosing new tires. For example, a tire size of 225/50R17 means the tire is designed for a rim with a 17-inch diameter.

Replacing car’s tires

Tires should be replaced when the tread depth is below 2/32nds of an inch or if the tires are over six years old, regardless of tread depth. Regularly inspect your tires for wear and damage to ensure your safety on the road.

Reading a tire size code

A tire size code is a series of numbers and letters on the sidewall of your tire that provides essential information about the tire’s specifications. The code includes the section width (the linear distance across the tire cross-section), aspect ratio (the height of the tire’s cross-section as a percentage of the section width), construction type (e.g., radial), and rim diameter (the diameter of the wheel from one bead seat to the other). Understanding these codes can help you choose the right tire for your vehicle.

Additional Things Drivers Should Know About Their Tires:

Tire Age:
- Tires degrade over time, even if the tread is still good. Check the manufacturing date on the sidewall to determine the tire’s age.
Tire Load Capacity:
- Each tire has a load-carrying capacity. Not exceeding this limit is crucial, as it can affect handling and safety. The load capacity is indicated by the load index on the sidewall.
Tire Tread Wear Indicators:
- Tires have built-in tread wear indicators (usually bars) that become visible as the tread wears down. When these indicators are visual, it’s a sign that the tire may need replacement.
Driving Conditions:
- Different tires are designed for specific driving conditions. Consider whether you need all-season, summer, or winter tires based on your area’s climate and driving conditions.
Tire Rotation Schedule:
- Regular tire rotation helps ensure even wear on all tires, extending their lifespan. Follow the recommended rotation schedule outlined in your vehicle’s manual.
Alignment and Balancing:
- Proper wheel alignment and balancing contribute to even tire wear. If you notice uneven wear patterns, vibrations, or the vehicle pulling to one side, it may be time for alignment or balancing.
Pothole and Road Damage:
- Be cautious of potholes and road debris, as they can cause damage to tires, including bulges, cuts, or punctures. Regularly inspect your tires for any visible signs of damage.
Spare Tire Condition:
- Check the condition of your spare tire periodically. Ensure it is properly inflated and the tread is in good condition, as it’s your backup in case of a flat or blowout.
Tire Pressure Monitoring System (TPMS):
- Many modern vehicles have a TPMS that alerts you when tire pressure is low. Pay attention to these warnings and address low tire pressure promptly.
Driving Habits:
- Aggressive driving, high speeds, and sudden stops can contribute to increased tire wear. Drive responsibly to maintain the longevity of your tires.
Emergency Tire Kit:
- Familiarize yourself with the tools and instructions in your vehicle’s emergency tire repair kit. This kit may include a spare tire, jack, lug wrench, and instructions on how to use them.

Regular tire maintenance, periodic inspections, and prompt addressing of issues contribute to safer and more efficient driving. Always refer to your vehicle’s manual and consult with professionals for specific recommendations related to your vehicle and tire type.

Conclusion

Understanding tire sizes and how to read them is crucial for maintaining your vehicle’s performance and safety. Whether it’s choosing the right tire size for your car, knowing when to replace your tires, or understanding the difference between summer and winter tires, being informed helps you make the best decisions for your vehicle. Remember, it’s always best to consult a tire professional when in doubt.