Understanding Tyre Load Ratings for Heavy Machinery

In heavy industries like mining, agriculture, and construction, tyres are more than just components — they are critical to equipment performance and safety. One of the most essential, yet commonly misunderstood, aspects of a tyre is its load rating.

This guide breaks down what tyre load ratings mean, why they matter, and how to choose the right load-rated tyres for your heavy machinery in Africa.

What Is a Tyre Load Rating?

A tyre load rating is a numerical code that represents the maximum weight a tyre can safely carry at a specified pressure. This rating helps ensure your tyres can support the weight of your machine and its payload without compromising safety.

For example:

• A tyre with a load rating of 160 can carry up to 4,500 kg.

• Ratings are paired with speed ratings to define maximum performance parameters.

Always refer to the manufacturer’s data sheet for precise load capacities.

Why Load Ratings Matter

Choosing the wrong load rating can lead to:

• Tyre failure under load

• Machine instability and unsafe handling

• Accelerated wear and overheating

• Regulatory non-compliance

In harsh African job sites, from mines to rural farms, under-rated tyres may not survive terrain stress, leading to downtime and safety risks.

How to Read Load Ratings

Tyre sidewalls include a load index (e.g., 160) and sometimes a ply rating (e.g., 12 PR). These numbers link to international charts indicating weight capacities.

Example markings:

• 23.5R25 193B

  • "193" is the load index

  • "B" is the speed symbol

  • "23.5R25" indicates size and type

Use a load index chart to cross-reference these numbers with the corresponding load in kilograms.

Matching Load Ratings to Machinery

To select the correct load-rated tyre:

1. Know your machine’s operating weight (including attachments and fuel)

2. Add expected payload (e.g., materials or tools carried)

3. Divide total load per axle based on configuration (2-axle, 3-axle, etc.)

4. Factor in dynamic loading (from bumps, uneven terrain, or sudden stops)

For example, a 25-ton loader carrying 10 tons of material will need tyres that handle at least 17.5 tons per axle under working conditions.

Considerations for African Conditions

African terrains pose unique challenges that affect load management:

• Extreme heat: Increases internal tyre pressure and accelerates wear

• Rough terrain: Adds dynamic stress

• Long working hours: Demand tyres with higher endurance

This makes it critical to choose tyres not just for capacity, but also for:

• Heat resistance

• Casing strength

• Off-road traction

BKT Tyres and Load Rating Confidence

BKT’s range of heavy-duty tyres is rigorously tested for load performance under real-world conditions. Options like the BKT EARTHMAX series are engineered with:

• Reinforced belts and sidewalls

• High-load indexes

• Special compounds for African climates

Examples include:

• EARTHMAX SR 30 for articulated dump trucks

• EARTHMAX SR 45 M for large loaders and dozers

• EARTHMAX SR 53 for underground and abrasive environments

These tyres deliver confidence where it matters—on job sites with high payload demands.

Common Mistakes to Avoid

• Ignoring inflation pressure: A tyre can only carry its rated load at its rated pressure.

• Using mismatched tyres: Different load ratings on the same axle can cause imbalance.

• Exceeding speed rating: Higher speeds reduce load capacity.

• Failing to inspect tyres regularly: Cracks, bulges, and underinflation degrade load performance.

Final Thoughts

Understanding tyre load ratings is essential for safe and efficient heavy machinery operations. It protects your team, extends tyre life, and ensures compliance with safety standards.

Before your next tyre purchase, consult your equipment manual and a trusted tyre expert to match load ratings with real-world demands.

Choose right. Carry safely. Maximise uptime with the correct load-rated tyres.