Crash tests carried out by Ford in the US have showed that not all 'copy' replacement vehicle parts are up to standard when it comes to safety and the cost of repair when an accident occurs.

Low-speed crash tests showed that a commonly used copy bumper beam absorbs less crash energy than the vehicle's original equipment or a genuine Ford replacement part.  The tests also showed that vehicles with the copy were more likely to experience unintended airbag deployments during low-speed collisions.

The carmaker said this could lead to higher repair costs. Repair estimates showed aftermarket copy bumper beams can more than double the repair costs after even a low-speed accident compared to a genuine Ford replacement part.

Paul Massie, Ford powertrain and collision product marketing manager, said: “These tests raise more questions about unintended airbag deployments in the event of a future crash. They also highlight that less-expensive copy parts could lead to much higher repair costs down the road.”

He added that aftermarket copy parts are parts unauthorised by the vehicle manufacturer, often constructed with substandard materials in order to be marketed as a cheaper alternative to authorised replacement parts.

Ford examined OEM and aftermarket copy bumper beams for the Ford Mustang from the 2005 through 2009 model years.  The parts were first put through a 6mph frontal impact sled test, then corresponding bumper absorbers and bumper isolators were added for 5mph and 8mph full-vehicle flat barrier crash tests.

Data from the 8mph crash barrier test demonstrated that the amount of crash energy absorbed by the aftermarket copy bumper beam is less than that of the OEM beam. The data also showed that the frequency of airbag deployments at low speeds will increase with the use of the copy bumper beam, absorber and isolator because the copy parts do not transmit the crash pulse as effectively to the crash sensors to indicate when an airbag should be deployed.

Damage estimates following the 5mph crash test put the repair cost for the vehicle fitted with aftermarket copy parts at US$2,982, almost two-and-a-half times the $1,224 estimate for the vehicle with genuine Ford parts.

Estimates after the 8mph crash came in at $3,816 for the aftermarket vehicle and $3,441 for the Mustang with genuine Ford parts.  In cases where the crash resulted in unwarranted deployment for both front airbags, the repair cost for the vehicle with copy parts would jump to at least $5,394.