98 'Burb: Cruise Control References What?

Anybody know what cruise control uses to tell whether to apply more or less power?
I'm thinking about long drives on straight, snow-covered roads.
In the past, I've gotten into minor trouble a couple hours into a drive doing,
say, 35 mph over snow on a straight flat road that very gradually starts to incline.
What seems to happen is that as the incline increases, the driver applies a little more power to maintain speed - and the tires come a little closer to the limits of their adhesion. Then, at some point, right at the limit of adhesion, the incline increases a little more. The driver applies a little more gas and suddenly the wheels are spinning like crazy and the car fishtails until the driver catches on to what's happened.
I'm thinking that if cruise control works by measuring wheel rotations, if might assist in preventing that scenario. When the wheels brake loose, cruise control thinks the vehicle is going too fast, and does what the driver would do: backs off on the power - but in a hundredth of a second instead of a half second or even a second or so if the driver is sufficiently zoned-out...
Anybody tried cruise on snow?
--
PeteCresswell

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(PeteCresswell) wrote:

You really shouldn't be use cruise on any situation that slick as you want to have the extra control.
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(PeteCresswell) wrote:

    Cruise Control does not smoothly apply power on a incline. It will let vehicle speed drop, then open the throttle by as much as 25%. In snow, you need to have the cruise off.
    A tires traction in snow varies. There is no set speed at which your tires will lose traction, on a set grade.
    An Example: My 87 Astro van,Gov-Lock, GoodYear Eagle ST's 225/75/15's. 3 Inches of snow 12% grade 1 mile long. Took me 15 minutes @ 5MPH forward speed, side switching the locked rear end by letting off the throttle.
    Same hill, 3 weeks later 6 inches of snow, same van, same tires. Walked right up it at a steady 15 MPH.
    The difference? The type of snow. Charles By Side Switching, I mean which direction I was fish tailing.
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Cruise controls that I have used will not back off the throttle if it is mechanically advanced. You can increase the throttle manually and when released, if the cruise control is set for a lower speed it will let the vehicle coast until it reaches that lower speed. If the transmission shifts to a lower or higher gear (or shifts into lockup) while the cruise control is controlling the throttle, that might be sufficient to break adhesion.. A similar problem occured with manual transmission cars with overdrive. Overdrive was an addition gearing behind the tranmission to drop the 1 to 1 output to about 9 to 10. It was shifted by vacuum and could shift at an inopportune time in slippery conditions.

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