Almost half of all cars on Europe's roads with 100,000 km on the clock could have damaged or badly worn shock absorbers, with serious implications for road safety.
That's one result of a "testing tour" carried out by shock absorber manufacturers Tenneco Automotive in Germany, Italy and the Benelux countries over the past few months. The results were released in France this week.
Tenneco's Monroe ride control systems are the most widely used as original equipment in Europe, and the second most widely used in the US. Its mobile units tested 16,500 cars in the survey, which was carried out in association with dealers and local authorities. The worst result was in Germany, where 52.8 per cent of cars tested were found to have one or more defective shock absorbers.
The equipment is a key safety component, on which the efficiency of the other elements of the "safety triangle" - brakes and tyres - rely to work properly. If the shock absorbers aren't working right, the already-small "contact footprint" of a car's tyres on the road gets even smaller. Defective shock absorbers also cause driver fatigue and discomfort, which is known to contribute to an increasing number of road accidents.
The efficiency of shock absorbers declines dramatically after around 80,000 km, and Monroe recommends replacement within a "safety threshold" of 60,000-75,000 km. "Because shock absorbers are a hidden component, motorists don't pay attention to them," says group aftermarket product manager Mark Tejedor.
The figures are blunt. With shocks that are 50 per cent off optimum, cornering stability declines by 7 km/h. The difference in aquaplaning on wet roads is 109 km/h instead of 125 km/h. Driver fatigue increases by 26 per cent. While the cost of a set of new shocks might seem high, if they're not replaced there will be increased and expensive wear on other drivetrain elements, including drive shafts, transmission, steering, wheel bearings and tyres.
There are no EU regulations directing the performance requirements of shock absorbers. Tenneco says it is working to try and have a standard introduced at European level. But in the meantime, any checks at national car testing level are left to the individual testing operations. Subsequent to having their cars tested, around a third of motorists renewed their shocks when they were given the report on their condition. "This indicates that when motorists are told how they can make their cars safer, they will do so," said Tenneco technology director Koen Raybrouck at the presentation of the results.