Readers of this blog know that Baurspotting takes safety issues quite seriously. We have previously done a number of posts on working on your car safely (search this blog for 'jack stand safety'). Today we have an opportunity to present a little information on how your car keeps you safe. Thanks to bimmerforums member conv440 for posting this, and thanks to the members who contributed to the discussion, TomD in particular.
These pics were posted today in E21 bimmerforums. A member's (conv440) teen son was rear-ended 'hard' while making a left turn. First of all, and most importantly, no one was hurt in the collision, thank goodness. Secondly, although negotiations with the insurance company continue, it appears that this will be the end of this particular E21 (1983 320iS, btw). Hate when that happens. C'est la vie.
However, since there always seems to be a lot of discussion on the pros and cons of the US (diving board) bumpers, I thought it maybe instructive to examine these pics a little.
Note the crinkling of the rear quarter panel, and the apparent lowering of the entire trunk.
Again, the wrinkled rear quarter, trunk lid popped up, and the kink in the black 'accordion' section of the bumper. The right side of the bumper is pushed in.
Wrinkled rear quarter panel; left side of bumper is slightly distended away from the body. Trunk lid appears seated properly on the left side.
The initial focus of the forum discussion was, naturally, gratitude in the fact that no one was hurt. This was followed by a series of comments about the US bumpers, and how it appears that they 'did their job', ugly though they may be. Resident Contrarian (and my friend) TomD then posted the following:
"sorry about the accident, but I'm going to disagree with your comment on the bumpers.
the mandated US bumpers were rated for a 5 mph (i believe) impact without damage. the impact with your car was absorbed by the chassis which was designed to do just that. so in this case the body did its job, not the bumpers."
This is why we pay TomD the big bucks. :) He gets us thinking, and I value his input. It certainly does appear that the chassis absorbed the impact, and crumpled downward. I agree with Tom on this, although I think it is hard to single the one factor out without including the other. In other words, the overall design of the chassis--- that looks like a classic rear 'crumple-zone', doesn't it?----- working together with the design of the 5 mph US bumpers gave us the result shown in the pics above. Together they did 'what they are supposed to do': protect the occupants.
Maybe it is just me but I find it remarkable that, despite all the damage from the impact..... the taillights remain apparently intact!! It must have been hit with what appears to be a glancing blow, at exactly the right height: bumper to bumper. Which, if you read TomD's wiki link, was ALSO a safety requirement of the bumper regulations!
Bear in mind that as I write this, I am in the middle of a project to REMOVE my 5 mph US Spec diving board bumpers, and replace them with 'Euro' bumpers.
Hmmm. Well, I am committed to replacing that front bumper, but.... this incident makes me think about that rear bumper. I may take my time replacing that one.
Here is the link to the bimmerforums post by conv440: