Garden and lawn mower tyre sizes can look confusing because different sizing systems are used for small tyres. The numbers generally tell you the tyre's overall diameter, section width and the diameter of the wheel rim it is designed to fit.

Understanding these measurements is important when replacing tyres on lawn mowers, ride-on mowers, garden equipment and other small machinery. Always check the size marked on the existing tyre and match it with the manufacturer's recommended size.

Let's look at two common examples: 13x5.00-6 and 4.10/3.50-4.

What Does 13x5.00-6 Mean?

1. Overall Diameter – 13 inches: The first number, "13", represents the approximate overall diameter of the inflated tyre. This is the distance from the ground to the top of the tyre when correctly fitted to the wheel.

2. Section Width – 5.00 inches: The second number, "5.00", indicates the approximate width of the tyre from one sidewall to the other.

3. Rim Diameter – 6 inches: The final number, "6", indicates that the tyre is designed to fit a wheel with a 6-inch rim diameter.

In summary, a 13x5.00-6 tyre has:

• Overall Diameter: Approximately 13 inches
• Section Width: Approximately 5.00 inches
• Rim Diameter: 6 inches

SWC supplies a range of garden equipment tyres in different sizes for lawn mowers, garden equipment and other applications.

What Does 4.10/3.50-4 Mean?

Another common small tyre size is 4.10/3.50-4. This sizing format is different from 13x5.00-6 and is commonly found on small garden equipment, trolleys, wheelbarrows and other utility equipment.

1. Nominal Width – approximately 4.10 inches: In this type of sizing, the first number is traditionally used to identify the approximate width of the tyre in inches.

2. Sidewall Height – approximately 3.50 inches: The height or cross-section of the sidewall (the distance from the outside edge of the tyre to the rim) in inches.

3. Rim Diameter – 4 inches: The final number, "4", indicates that the tyre is designed to fit a 4-inch diameter rim.

In summary, a 4.10/3.50-4 tyre provides the following information:

• Nominal Width: Approximately 4.10 inches
• Sidewall Height: Approximately 3.50 inches
  
• Rim Diameter: 4 inches

Why Are Garden and Lawn Mower Tyre Sizes Important?

Using the correct tyre size is important for safety, performance and proper clearance. A replacement tyre needs to fit the wheel correctly and provide enough clearance from the mower deck, chassis, steering components and other equipment.

The wrong tyre diameter can also change the operating height of the equipment, while the wrong width may cause clearance problems or prevent the tyre from fitting correctly on the rim.

When replacing tyres, check the complete size marking on the sidewall rather than relying only on the appearance of the tyre. Two tyres can look similar while having different rim diameters or dimensions.

How to Check Your Lawn Mower Tyre Size

The easiest way to identify a replacement tyre is to look at the sidewall of the existing tyre. The size will normally be moulded or printed into the rubber.

For example, you might see:

• 13x5.00-6
• 4.10/3.50-4
• 18x8.50-8

Record all of the numbers before ordering a replacement. The rim diameter is particularly important because the tyre must match the wheel it is being fitted to.

Tyres, Wheels and Complete Wheel Assemblies

Depending on your application, you may only need to replace the tyre. In other situations, replacing the complete wheel and tyre assembly can be easier and more cost-effective.

SWC supplies replacement tyres and tubes as well as a range of wheels for garden equipment, trolleys, hand trucks and other applications.

For applications where punctures are a concern, puncture-proof replacement wheels can provide a low-maintenance alternative to pneumatic tyres.

Need Help Finding the Right Tyre?

If you're unsure which garden or lawn mower tyre you need, check the numbers on the sidewall of your existing tyre. The tyre size, application and rim information can help identify the correct replacement.

If the markings are difficult to read, contact SWC and provide the tyre size, equipment type and any other information shown on the existing wheel or tyre. We can help you find a suitable replacement.

Browse the full range of garden equipment tyres at SWC for replacement tyres and wheels throughout New Zealand.