What Do Tyre Numbers Mean?
Tyre sizes may look confusing at first, but every number and letter on a tyre has an important meaning. Understanding tyre sizes helps you choose the correct tyres for your vehicle, improve safety, and maintain proper handling.
Common tyre sizes in New Zealand include:
- 195/65R15
- 265/60R18
- 33x12.5R20
These numbers tell you the tyre width, profile, construction type, and wheel diameter.
Example: 195/65R15 Explained
Let’s break down 195/65R15.
195
This is the tyre width in millimetres.
The tyre measures approximately 195mm wide from sidewall to sidewall.
65
This is the tyre profile or aspect ratio.
It means the tyre height is 65% of the tyre width.
R
The “R” stands for radial construction.
Most modern tyres are radial tyres.
15
This is the wheel diameter in inches.
This tyre fits a 15 inch wheel.
What Does R Mean on Tyres?
The letter “R” means radial construction.
Radial tyres are designed for:
- Better road grip
- Improved comfort
- Longer tyre life
- Better fuel economy
Almost all passenger and 4x4 tyres sold in NZ today are radial tyres.
What Is Load Rating?
The load rating shows the maximum weight a tyre can safely carry.
Example:
- 91 = load index
A higher load rating means the tyre can carry more weight.
Load ratings are especially important for:
- Utes
- Vans
- Commercial vehicles
- Vehicles carrying heavy loads
What Is Speed Rating?
The speed rating is shown by a letter at the end of the tyre size.
Examples:
- T
- H
- V
- W
Example:
- 91V
The “V” indicates the maximum speed capability of the tyre.
Different speed ratings affect:
- Handling
- Performance
- Stability
What Does XL Mean on Tyres?
XL stands for Extra Load.
XL tyres are built with stronger construction and can carry heavier loads than standard tyres.
XL tyres are commonly used on:
- SUVs
- Utes
- Performance vehicles
- Vehicles carrying heavy loads
Understanding 33x12.5R20
Off-road tyres often use a different sizing format.
Example:
33x12.5R20
33
Overall tyre height in inches
12.5
Tyre width in inches
R20
Fits a 20 inch wheel
This size is popular on:
How to Choose the Right Tyre Size
Choosing the correct tyre size depends on:
- Vehicle type
- Wheel size
- Suspension setup
- Daily driving or off-road use
- Load requirements
Always choose a tyre size suitable for your vehicle and wheel specifications.
Popular Tyre Sizes in NZ
Popular tyre sizes include:
- 195/65R15
- 205/55R16
- 265/65R17
- 265/60R18
- 33x12.5R20
These sizes are commonly used on passenger vehicles, SUVs and 4x4 utes in New Zealand.
Shop Tyres at Zoom Tyres NZ
Zoom Tyres offers:
Available in a wide range of sizes for Ford Ranger, Toyota Hilux, Nissan Navara and more.
Located in Otahuhu, Auckland with NZ-wide shipping available.
FAQs
What does 265/60R18 mean?
It means the tyre is 265mm wide, has a 60% profile, radial construction, and fits an 18 inch wheel.
Can I change tyre size?
Yes, but the tyre must remain suitable for your vehicle and wheel specifications.
What is the difference between AT and MT tyres?
AT tyres are all terrain tyres designed for mixed road and off-road use. MT tyres are mud terrain tyres designed mainly for off-road driving.
Are bigger tyres better?
Bigger tyres can improve ground clearance and appearance but may affect fuel economy, handling and road noise.