03.What we test
Each tyre design varies in its tread pattern and rubber mix and is a compromise between a number of requirements, such as grip and durability.
A soft tyre provides better grip but also leaves more rubber on the road, and won’t last as long as a harder model. Racing tyres are an extreme example: they’re very soft and almost glue the car to the track, but usually only last for (part of) one race.
Our cornering and braking tests assess the tyres’ grip, but not their durability. Tyre wear is difficult and expensive to test properly — for example, several European consumer organisations and motoring clubs carry out a joint test, part of which is a convoy drive over 10,000 kilometres, using identical cars. Unfortunately we can’t join their test, because most European tyres are different from Australian ones. And we can’t afford to run a similar test on our own.
However, some tyres have a tread wear rating that can give you some idea of how long a tyre should last compared with others used in the same conditions.
We tested the tyres at three different speeds in dry and wet conditions: In the dry, all the models easily mastered our test corner at 75 km/h, but none managed to hold the test car in its lane at 85 km/h. At 80 km/h, the SIAMTYRE (it scored 60%) didn’t quite match the other models (80–100%).
In the wet, none of the tested models had problems at 65 km/h, and all scored between 80% and 100% at 70 km/h. But the CONTINENTAL was the only model to keep the test car in the lane at 75 km/h.
Our tests show that 5 km/h can make the difference between your car holding a corner quite comfortably and going out of control.
We measured the following average stopping distances:
- From 50 km/h, from about 7.5 m (DUNLOP, GOODYEAR) to 9.5 m (CONTINENTAL, YOKOHAMA) in dry conditions, and about 10 m (FIRESTONE, GOODYEAR, HANKOOK, KELLY, PIRELLI) to 12 m (CONTINENTAL) in the wet.
- From 80 km/h, from about 24 m (FIRESTONE, SIAMTYRE, TOYO) to 26.5 m (YOKOHAMA) in the dry and about 28.5 (MICHELIN) to 34 m (SAVA) in the wet.
In an emergency situation, a few metres can of course mean the difference between stopping in time and having a crash. However, our results are best-case. In real life, other factors have an effect as well:
- ABS: Our results were certainly helped by the anti-lock braking system (ABS) fitted to our test car. In an emergency situation like that simulated by our tests, you just slam on the brakes and the electronics ensure the car stops as quickly as possible without locking the tyres.
When driving a car without ABS, you have to adjust the force applied to the brake pedal to stop the tyres from locking up. This can be tricky, and it’d be much harder to achieve stopping distances as good as ours.
- Reaction time: Our test driver knew he was going to have to brake — in an emergency, you won’t. Half a second’s reaction time at 50 km/h means an additional 7 m stopping distance; at 80 km/h it’s an additional 11 m.
We’d like to thank:
- Holden for providing the test car.
- Deighton Motors in Warwick, Queensland, for valuable support throughout the project.
- Morgan Park Raceway in Warwick for their efforts to ensure a smooth test.
This article last reviewed December 2008.