Tenneco Automotive, has issued a winter warning about the risks of driving with worn shock absorbers, following research carried out by an independent institute.
Tests carried out by GTS and TÜV Rheinland, two independent research institutes located in France and Germany, provided a graphic demonstration of how worn shock absorbers can render ABS, ASR and ESP systems significantly less effective.
The manufacturer of aftermarket ride control and exhaust system products, including the brands Monroe, Walker and Fonos, is warning drivers that although shocks wear out gradually they become increasingly dangerous as they do so. Tenneco claims that it is important to have a vehicle’s shocks checked professionally every 20,000 kilometres, particularly as winter approaches.
Braking tests carried out on icy roads in the French Alps and on the snowy roads of St Moritz in Switzerland, showed that a car carrying four passengers, fitted with ABS, and 50 per cent worn shocks took 1.8 metres longer to stop from 35 km/h than it did when fitted with 100 per cent efficient Monroe shock absorbers.
Further tests showed that 50 per cent worn shock absorbers also affected the car’s anti-skid system. Tenneco claims that with 100 per cent efficient shocks, “the car had greater traction control, with a period of lost traction 37 per cent less than that experienced with 50 per cent worn shocks.” The vehicle with new shock absorbers was able to accelerate 16 per cent faster compared to the worn ones.
A more striking comparison was offered when ‘panic braking’ tests were conducted. A vehicle equipped with ABS and 100 per cent efficient Monroe shocks was driven at the constant speed of 50 km/h on a test stretch, after ‘panic braking’ the wheels continued to revolve because the ABS system avoided their blocking. Electronic instruments measured the braking distance from the start of the braking action to the final stopping point and the car took 28.8 metres to stop. A car fitted with 50 per cent worn shocks tested under the same conditions took 35.4 metres to stop.