Lately I've been thinking about all of these Ford/Firestone fatalities. Yes the tires are faulty but I'm somewhat surprised by all the lives lost in these rollovers. Is it a weight issue where the roof collapses under such load? Can we assume the structural integrity of our Audi's (no lightweight either) or Saabs.Volvos.Mercedes.etc. would protect us better given similar tire problems?

 

The structural integrity of your Audi is certainly better than that of an average SUV but the main reason that you're safer in any sedan with a tire problem is that there is a much lesser chance to roll over in the first place.
And if you have quattro that chance is even smaller.
I've experienced a font right tire explosion in my V8 at about 75mph when passing a semi truck and the car remained unbelievably stable. My wife didn't even noticed that there's anything wrong with the car. The tire was shredded to pieces when I stopped.
After this experience I cannot go back to a 2 wheel drive car.

 

average sedan is structurally much more rigid than average SUV. And, most SUV's have a very high CG. OK for off road, less so for off ramps.

 

With our sedans the weight is much closer to the ground than a typical SUV. Remember you need ground clearance for off roading. So if you can think in three dimensions for a sec. you can easily picture where this weight is located on an suv. If something with more weight towards the top starts to fall over compared to something with more weight toward the bottom......I think you understand what happens.

 

By purposely underinflating the tires Ford is trying to ensure that any lateral roll motion incurred in the vehicle is damped. Just as a shock absorber dampens road impact, underinflated tires serve the same purpose here for the entire chassis. (Think about driving your car with solid metal members in place of the shocks down even the smoothest of roads...Ouch!) More highly pressurized tires yield less cushion and so will be less able to absorb the shock of this kind of motion, and this can result in them becoming a "pivot point" of sorts, enabling the body to roll over onto it's side. The problem is that the increased flex and stress the tire undergoes in this configuration (increased rolling resistance) drastically increases heat and can cause the tires internal structures to wear or break down much more easily.

So I guess the bean counters told them it would cost less to replace 3.3 million tires (or whatever the number is) than to settle a couple of wrongful death suits, eh? That must be the price of high ground clearance and a commanding view of the road these days....

Just my $.02.

 

strength of the roof pillars. 99% of the engineering for crash worthiness goes into the front,rear and sides. There does not appear to be a way, sans roll cage, to make a roof strong enough to withstand a high speed rollover. It just would not be economical and the aesthetics would be quite interesting.

In addition, all that extra roof area/headroom is making it like a big giant greenhouse. The problem is that the greenhouse does not increase in strenght proportionately with the increase in weight/size of the vehicle.

Remember that BMW test driver who rolled the new 3 series in front of the media several months ago. That thing really took a tumble after it tripped without warning. Due to the relatively low slung roofline, the car absorbed the energy in the side and then basically just kissed the roof depressing it some in the forward portion and then continued the process of rolling with the roof no longer in the way of the roll.

The BMW guy crawled out of the car and walked away. Take two aspirin and call me in the morning. BMW changed something in the car to mitigate the tendancy so there would not be a repeat performance.

In the SUV's it appears that the roof is absorbing substantially more energy before continuing on it's roll (granted this is happening in fractions of a second).

I have seen many of the photographs of the SUV rollovers and it's hard to tell what damage was from the roll and what damage was from the rescuers. The roof area appears to have collapsed several inches and maybe as much as 18 or more inches. There is no way a human inside of the passenger cage can take that much of a reduction in head room.

All I know is that if I am going roll in a vehicle without a roll cage, I want to be as low as possible. That includes the car body and my body. Thank goodness I got rid of my SUV beast. Luck of timing.

Side curtains probably would not do much in the SUV's either. I am glad the Audi has them and I am much happier it is a low slung sedan.<p>00 2.7T
17"ATP/Yoko S

 

So much so liken it to driving in a cage. Often it's easy to forget this or even overlook this if untrained. A rock solid chassis is the key, slung low (with a roll bar). A worthwhile $0.02.

 

It was amazing, this morning on my way to work there was serious pile up at the off ramp I usually take. 5 vehicles in various stages of destruction and all of them an SUV of one sort or another, with 2 of them appearing to have rolled. So here I am musing that we own one of those behemoths (an Explorer Sport Track w/16" Firestone ATX's none the less) and have purposely put the beast in a slide (in a parking lot under controlled conditions, of course!) just to get used to the feel or "tipping" sensation before it would actually happen. And while obviously not our 4.2, I was impressed at how gentle and benign the slide was with no hint that it was going to tip over, making it very catchable. So now I'm convinced that all of these morons must be on their cell phones not paying attention to the task at hand and are simply driving straight off the road! But now I'm going to get on my soap box about driving according to your car's (or truck's) capabilities....I wonder where I put the keys to the A6?!

2000 A6 4.2
Ming Blue
2001 Sport Trac

 

SUVs are really built for low speed travel. they aren't really made to be driven the way 90% of the owners use them.

i read somewhere that less then 5% of them ever go off road. so what is the point of owning it. sure to impress friends. i rather spend the 30 or 40k on an Audi or any of the other makes in that price range.<p>Bill