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ABS, Ice Warning



Dave_Edmondson@domain.elided writes:

>On the subject of ABS and computers doing things that drivers should be able
>to do, the computer can sense the behaviour of each wheel independantly and
>adjust the braking when THAT wheel starts to lock up, no driver can do that.

I believe most BMWs only have three-channel ABS, not four-channel.
Only four-channel systems independently brake all wheels.  A
three-channel system like the one on my 328is handles the front wheels
independently and the back wheels as a pair.  It's a disadvantage if
one rear wheel is on a slippery surface and the other is not (it will
only brake both wheels until the one with less traction starts to
slip), but it's not a big deal because the vast majority of the braking
force is produced by the front tires anyway.


"Alberto SCHILEO, DCC/USD" <Alberto.SCHILEO@domain.elided> writes:

>>BTW, has anyone seen the "black ice sensors" that SAAB used to have?
>
>    my 328is does it via the OBC.  When it detects an exterior temp of 2 or 3 
>degrees celsius under the fender (I do not remember which is the treshold) it 
>will gong, and display the outside temp to alert you that it's probably icy on 
>the road.

I would phrase that as "possibly icy on the road."  The gong sounds almost
every time I drive during the Midwestern winter, yet there is very rarely
ice on the road--the OBC cannot know if the road is wet.  Even if you see
for yourself that the road is wet, you have to evaluate whether the salt
on the road (where I live, anyway) has depressed the freezing point of water
enough to eliminate the possibility of ice forming.

The warning is almost useless for the conditions I drive under, but I suppose
it could be more valuable in other parts of the world.

Rob
opus64@domain.elided