If you’ve noticed small cracks or splits on your tyres, especially along the sidewalls or tread edges, you might be wondering: “Will this cause my car to fail a roadworthy?” It’s a valid concern—tyres are a key safety item, and even minor defects can be a red flag during inspection.
Here’s what cracked tyres mean, how they affect roadworthiness in Australia, and when it’s time to replace them.
1. What Are Cracked Tyres?
Cracked tyres typically show small splits or lines on the sidewalls or in the tread grooves. These can be shallow surface cracks or deeper structural splits and are usually caused by:
Age: Rubber degrades over time, especially in harsh Australian conditions with high UV exposure.
- Under-inflation: Driving on low-pressure tyres stresses the sidewalls and can cause premature cracking.
- Dry rot: Common in cars that sit unused for long periods, particularly outdoors.
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Poor storage or exposure to chemicals: Harsh detergents or excessive sun can dry and crack the rubber faster.
While some fine cracks may seem cosmetic, deeper or widespread cracking can seriously compromise tyre safety.
2. Can You Fail a Roadworthy Due to Cracked Tyres?
Yes, you can. In Australia, all tyres must be in a condition that is safe and roadworthy at the time of inspection. According to most state roadworthy guidelines, you may fail if:
- Cracks are deep or extensive, especially across the sidewalls
- You can see exposed cords or internal fabric
- There are signs of bulging, tread separation, or deterioration
Even if your tread depth is legal (minimum 1.5mm across the tyre), you can still fail a roadworthy if your tyres show signs of structural ageing or cracking.
3. When to Replace Cracked Tyres
Here’s how to tell if a cracked tyre should be replaced:
- Cracks are deeper than 1–2mm
- Multiple or spreading cracks appear around the tyre
- You see fabric or steel cords through the cracks
- The tyre is more than 6 years old, even if it looks okay
- You experience vibration, uneven wear, or poor grip
Any tyre shop or mechanic offering roadworthy inspections will point these out and advise replacement if they’re unsafe.
4. How to Avoid Tyre Cracking in the First Place
Prevention is the best cure. Here’s how to extend your tyres’ life:
- Maintain proper tyre pressure
- Rotate your tyres every 8,000–10,000 km
- Store your car in a garage or shaded area if possible
- Avoid leaving your vehicle parked for long periods without moving it
- Replace tyres every 5–6 years, regardless of tread condition
In Summary
Yes—cracked tyres can cause your vehicle to fail a roadworthy in Australia, especially if the cracking is deep, widespread, or shows signs of structural weakness. Even if they pass inspection, cracks are an early warning sign that your tyres may not be safe for much longer.
If you notice cracking, don’t wait—have your tyres inspected by a qualified mechanic or tyre technician. When it comes to road safety, tyres are not something to take lightly.