How many miles will a tire last? How does the tread behave over its lifetime? Does the tire wear uniformly or unevenly? The staff in the Wear Testing Indoor test department are able to answer these questions. This department has a total of eleven drum test rigs, comprising eight for car and motorcycle tires and three larger ones for truck tires. Industrial tires for forklift trucks, airport vehicles and agricultural machinery can have their wear characteristics tested here too.
The tread surfaces run on rotating drums that simulate a road surface in the test rigs. A maximum of six car tires can be tested at the same time on the drums, which measure up to three metres in diameter and weigh as much as six metric tons. When the drums rotate at a specified speed, their mass and surface simulate the road surface and driving speed.
The tread surfaces run on rotating drums that simulate a road surface in the test rigs.
These “artificial surfaces” are more abrasive than roads and so they speed up the rate of wear compared with real-world use. The test rig has no unevenness, potholes or varying road surfaces of the kind found on everyday roads, resulting in ideal, reproducible test conditions. The test rigs can model the average annual distance covered by a car tire in just ten days, resulting in major time and cost savings over outdoor testing on public roads or proving grounds.
A variety of parameters, such as load, tire pressure and camber, can be set for the individual test positions, enabling a broad spectrum of driving situations to be simulated.
A test run can last up to eight days for car tires and as long as 14 days for truck tires. The test results give a very clear indication of how a tire wears under different conditions, showing, for example, whether freestanding tread blocks tend to suffer heel and toe wear or if diagonal wear may occur. The results are fed back to departments such as product development, the OE department and quality management for tire production, depending on whether testing is being carried out on prototypes, specific tires for individual vehicle models or random samples from ongoing production. Other R&D departments are also involved, such as the Mixing Lab and Compound Testing Lab.