Re: [SystemSafety] Wheel detachment from a moving car / problem was solved many years ago, not widely adopted

From: Bernd Sieker < >
Date: Tue, 26 May 2015 17:49:54 +0200


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On 26.05.2015 17:15, Steve Tockey wrote:
>
> I've got no idea how many miles I've driven in my life, but
> probably in the neighborhood of about 350,000. In all that time,
> I've seen wheels lost--by other people--twice. Once was on a
> freeway in California, I was headed north, they were headed south
> on the other side. I remember seeing the wheel bouncing down the
> southbound lanes as the car it came of at came to an abrupt halt.
> The other was when a wheel fell off a boat trailer.
>
> I've seen the explosive failure on large trucks (lorries) twice
> just in the last 5 years. Big tires, big bang with lots of noise.
>
> US drivers commonly see the fallen off tread from failed retread
> tires. You probably can't drive 50 miles without seeing that.

Yes, truck tyre treads are common here, too, and at least twice I've seen a truck with a burning tyre and once an armoured personnel carrier. Tyre failures on caravans are particularly frequent, we've had three on one trip with my parents; most people only use them once a year, and there is (or was) no legal limit on tyre age, only on tread groove depth, so they tended to become brittle from age and UV radiation. I've also seen plastic snap-on ("snap-off") wheel covers. But never entire wheels. I've probably driven in the neighborhood of 300,000. But only km, not miles.

Maybe the mandatory biennial technical inspection of cars in Germany does something after all.

>
> I remember my parents having Chrysler cars in the 1960 with the
> left- and right-hand wheel nuts. I remember being told that it was
> that way because of tire rotation it would tend to tighten loose
> wheel nuts rather than loosen them. It would be interesting to
> analyze when wheels do fall off do they tend to fall off the same
> side?? (thus, arguing for going back to the left- and right-hand
> format).

Na´vely, I wouldn't even know which way they should thread to be more resistant to working themselves loose with time. After all, torque on the wheels works in different directions during acceleration and braking. And although in "cruise" torque drives the wheels forward, braking forces can typically be higher, more abrupt and include more vibration (e. g. from ABS) than acceleration forces.

>
> Cheers,
>
> -- steve

Bernd
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