Airbags only deploy at 20-30 mph or some much higher speed, no?

 

I believe redundant accelerometers are employed in most airbag deployment designs.
This would allow for deployment in an impact where you are not moving and someone drives directly into the front of your car (or a side impact if so equipped).
Think change in velocity, not absolute velocity.

This is most likely the reason why airbags would/did not deploy in a 'slow' rollover. You are dealing with the derivative not the integral of velocity; so you could put your Cayenne on a rotisserie and spin it (about any axis really) and you would not deploy airbags.

(sorry, back in the 80's, I designed inertial sensors for most weapons systems...most of which sit in their silos quietly waiting)

 

Lewis, "sorry" not necessary. Thanks for the information...

 

Lewis,
You are spot on. These SRS sensors "arm" at somewhere around 3G's, and "trigger" at higher levels.
The original post revisits a question that really plagued product planners - namely, how does one achieve the demanded high speed dry weather performance whilst giving some "utility", especially in poor weather. Unfortunatly, there's no good answer (BTW - the BMW X5 tire is NOT rated to the same top speed as the Cayenne), so the decision was taken to advise purchasers/owners of the need to fit proper tires for a given scenario. With personal experience, the "summer" tire set gave very reduced grip during a recent "cold snap" (lows in single digits). Since I've taken up storage space with winter tires for the Box, I don't have good snows for the CS, so I leave it alone in very poor weather. Once the Box goes away (after next summer the lease is up), I'll spring for a good set of winter wheels/tires.
J
PS - here's a thought - invent a tire that can handle 2+ tons and 500hp on a track AND stay flexible in cold temps & snow. You'll make $$$

 

V-rated Pirelli Scorpions - will not get to the highest speeds the C is capable of but will get past 100+ and still remain flexible in cold temps & snow

 

I have my fun in the turns. If you just mash the gas in a straight line, buy a Mustang Cobra, 'casue you threw your money away

 

Oh, I thought everyone went more than 70 in the turns on two wheels or four..