Rear Bumper Shock Absorbers
 

Was in a motor vehicle accident- hit from behind. For the court case I need the engineering specs on the rear bumper shock absorbers- specifically, what minimum force is required to cause both shocks to fail. 2005 X5.

Anybody know where I can source this engineering info online?

You won't get it, it isn't the sort of thing manufacturers release.

You could buy a new part and test it, but that seems a little extreme.

Why do you need to know the force? Wouldn't it be better to know the speed of the other vehicle when it hit you (or when you hit it)? The force is a result of the speed and the mass, so you would need the weight of the vehicles to figure out the force.

The short answer is that if the vehicles are the same weight, there should be no damage (collapsing of the struts) up to a 5 mph impact. However, manufacturers can exceed the standards if they choose to. You could check the certification of the X5 for California, where BMW has to publish the impact performance under state law.

Read the following link, there is some good background information on this. While it is a US link, it includes reference to Canadian standards, and BMW and other manufacturers don't build different bumpers for those two markets. The manufacturers design the bumpers and certify that they meet the NHTSA standard. Check online and see whether the Canadian standards apply more so to SUVs than the US standards do.

Bumper Questions and Answers

Thanks JCL!

Great link.

FYI- this is an interesting exercise in accident reconstruction. Crash happened in a lineup at a school to pick up kids. Person who rear-ended us was on a cell phone. With the mass info on the other vehicle and a distance algorithym we are going to show they were either speeding at the time of hitting the brake, or hit the gas instead of the brake- distracted driver.

Thanks again for the help.