General Information & Terms and Conditions

The Importance of Correct Tyre Pressure

Maintaining the correct tyre pressure for a vehicle is an important factor in how much load its tyres can safely carry. The correct pressure will carry the weight without a problem. Too little tyre pressure will eventually cause catastrophic tyre failure.

Tyres are made of layers of fabric and steel encased in rubber. If a tyre runs low on air pressure, the rubber is forced to stretch beyond the limits of these reinforcements. This weakens the bond between materials and can cause tyre failure. Once weakened, a tyre will not “heal” even after re-inflation. For safety, tyres that have been run nearly flat should be replaced, not repaired.

Studies show that about one in four vehicles on the road is running on under-inflated tyres. This reduces fuel economy, handling, durability, and tread life. Tyre Pressure Monitoring Systems (TPMS) have been developed to warn drivers when tyres are under-inflated.

Types of Tyre Pressure Monitoring Systems

Direct Systems

Direct systems attach a pressure sensor to each wheel. These sensors send data to an in-vehicle receiver, warning the driver if pressure falls below a safe level. Direct systems are more accurate, reliable, and can indicate which tyre is low. Some systems allow tyre pressure checks directly from the dashboard.

Indirect Systems

Indirect systems use ABS wheel speed sensors to compare tyre rotations. A tyre with low pressure will rotate differently. While cheaper, indirect systems have limitations: they cannot detect when all tyres lose pressure evenly, they cannot specify which tyre is low, and they may generate false warnings on wet or icy roads.

Changing Tyre Size

Changing tyre size must be done carefully to maintain the same overall diameter. This is important because vehicle speedometers, traction control, torque, and gearing are calibrated to tyre diameter. Even a small change can affect speed readings and performance.

Tyre Size Calculation Example

1. Multiply tyre width by aspect ratio: 205 x 0.55 = 112.75 mm
2. Convert to inches: 112.75 ÷ 25.4 = 4.44 in
3. Double aspect height: 4.44 x 2 = 8.88 in
4. Add wheel diameter: 8.88 + 16 = 24.88 in overall diameter

When changing tyre size, the difference in diameter should not exceed 1% (ideally less than 0.5%).

Important Safety Notice: Do not change tyre size without consulting an expert. Incorrect sizing may cause accidents or vehicle damage.

Tyre Speed Ratings

The speed rating of a tyre is shown on its sidewall, represented by a letter. This indicates the maximum safe speed the tyre can maintain.

Always check the tyre speed rating before purchase. For questions, contact our team of tyre experts.

Tyre Load Ratings

The load rating indicates the maximum weight a tyre can carry. It is usually displayed after the tyre diameter and before the speed rating on the sidewall.

If you have any questions regarding tyre size, speed rating, or load index, please contact our team of experts before making a purchase.