Special Feature: Tyre Testing

All tyred up

Each year, Topcar subjects tyres of a particular size and profile to a gruelling testing procedure to establish how they perform – and how they compare. This time, we evaluate top-of-the-

range offerings from nine different tyre manufacturers in a popular 17-inch size used on many mid-size luxury sports saloons

The modern motor car is an amazing machine. Advances in virtually every sphere of automotive technology have resulted in vehicles that are more efficient, safer and faster than their predecessors.

Perhaps the most notable improvement in past years has been in the ride and handling departments, however.

Take Topcar’s double-lane change test results as a case in point. This international-standard handling test is designed to show up a vehicle’s ability in an emergency collision avoidance situation. The car under evaluation is piloted through a course that simulates a swap in lanes, with a return to the original lane, at as high a speed possible.

Although it may sound simple, this test is challenging for driver and vehicle alike, and graphically illustrates any dynamic shortfalls. The test is also an accurate indicator of the capability of the tyres fitted to the vehicle.

During the more than a decade of double-lane change tests completed by Topcar, the results have improved dramatically. For example, when it was tested in 1997, the E36 BMW M3 recorded an average speed of 123,4 km/h through the ISO-approved course. A few years on, the far more mainstream Mazda6 2.3 Sporty achieved a similar speed.

This test also demonstrates to what extent tyre technology has evolved. Were it not for modern tyres, vehicle designers would not have been able to push the envelope to the extent they have.

Today’s motor vehicles sport numerous features designed to keep the wheels on the ground when things go pear-shaped. Yet cutting-edge systems such as ABS, EBD and traction control all amount to nought if the vehicle’s tyres cannot generate friction with the road surface.

Tyre technology has advanced to such an extent that it is virtually impossible for a layman to keep track of the intricacies of tyre design. Tread patterns, rubber compounds and sidewall construction all contribute to a specific tyre’s characteristics. Additionally, the run-flat technology offered by some tyres allows the vehicle to be driven even after it has lost pressure.

With all of these advancements, one could be forgiven for surmising that this technology had reached its pinnacle. But tyre design is all about compromise. Manufacturers must decide whether to trade off performance against cost, ultimate adhesion against longevity, and dry grip against wet weather behaviour.

As tyres become more expensive, sacrifices made in other areas become smaller, to a point where top-of-the-range offerings can provide virtually everything the modern motorist may require.

It is this top segment of the market that we have chosen to investigate this year. The most typical 17-inch tyre sold is a 225/45 R17, fitted to vehicles such as Mercedes’ C-Class and the BMW 3-Series. As one would imagine, the tyres are pricey, and performance expectations high.

We took eight tyres from each of nine manufacturers – almost R125 000 worth of rubber – and subjected them to Topcar’s gruelling test. World karting and national off-road racing champion Mark Cronjé used a highly evolved Mercedes-Benz C180 Kompressor fitted with the optional sports package to burn all of this rubber.

How did the tyres compare? Read on to find out …

Rankings

CUMULATIVE SCORES
Overall Position Tyre model
Dry
handling
Wet
handling
Dry
braking
Wet
braking
Aqua
planing
1
Goodyear Eagle F1 GSD-3 6 1 2 1 3
2
Continental Sport Contact 2 2 4 tie 6 2 2
3
Bridgestone Potenza S-03 4 3 1 4 5
4
Michelin Pilot Sport 3 6 3 7 1
5
Pirelli P Zero Rosso 1 2 9 5 4
6
Falken FK 451 8 7 5 3 6
7
Yokohama AVS Sport 5 5 4 8 9
8
Toyo Proxes T1-S 7 9 tie 6 9 7
9
Dunlop SP Sport 7000 D 9 8 8 6 8