Don't Slip Up This Winter
Published: 6th January 2005
Check your shock absorbers before setting off
Tenneco Automotive, manufacturer of the world’s leading aftermarket ride control and exhaust system products under the Monroe, Fonos and Walker brands, says that driving with worn shock absorbers could potentially increase the risk of accidents this winter.
Shock absorbers help keep the car’s wheels in contact with the road – which is important for good braking and steering at the best of times, and particularly vital in winter conditions. However, shocks wear out gradually and become increasingly dangerous as they do so, but few drivers notice the symptoms, making it particularly important that they have their vehicle’s shocks checked professionally every 20,000 kilometres, particularly as winter approaches.
Independent research carried out by GTS and TÜV Rheinland, two independent research institutes located in France and Germany, respectively, has given a graphic demonstration of how worn shock absorbers can render ABS, ASR and ESP systems significantly less effective.
In a braking test on icy roads in the French Alps and on the charming yet dangerous snowy roads of St. Moritz in Switzerland, a top class car fitted with ABS carrying four occupants and 50% worn shocks took 1.8 metres longer to stop from 35 km/h than it did when fitted with 100% efficient Monroe shock absorbers.
Another car, this time a medium class car, equipped with ABS and 50% worn shocks and two occupants took an additional 1.2 metres to stop in the same GTS braking test, compared to its stopping distance with new Monroe shocks.
A second test showed that 50% worn shocks also affected the car’s anti-skid system. With 100% efficient Monroe shock absorbers, the car had greater traction control, with a period of lost traction 37% less than that experienced with 50% worn shocks. And even in the winter test conditions, the vehicle with new Monroe shocks was able to accelerate 16% faster compared to the worn ones.
Other tests showed that on a vehicle equipped with ABS and 100% efficient Monroe shocks driven at the constant speed of 50 km/h on the test stretch, after a “panic braking”, the wheels went on revolving since the ABS system avoided their blocking. As a result the car took exactly 28.8 metres to stop. The electronic instruments could measure the braking distance from the start of the braking action to the final stopping point.
Then, the test was repeated with the same car fitted with 50% worn shocks: constant speed, sudden braking, steering wheel firm - yet this time the wheels blocked partially. The vehicle started skidding as the driver was not able to react and it stopped at a longer distance than in the previous test: the braking distance measured was 35.4 metres.
Driving a car with worn shock absorbers during winter is potentially dangerous not only in the mountains, but also on city roads. Mud and icy snow residues make the road surface uneven, which provokes the sudden jolting of wheels. Under these conditions, only high-performance shocks can guarantee the necessary grip to the road surface.
Monroe recommends all drivers to check their shocks and, if necessary, have worn shocks changed by a qualified mechanic before winter sets in.
According to Monroe experts, the best shock absorbers in terms of quality and safety are gas shocks, that ensure optimum road holding, immediate response and maximum safety and comfort all year round.
