Adrienne from Vail Colorado called in to settle a bet with her husband. He uses the cruise control on their Subaru on the downhill portion of the two passes between Vail and Denver. You told her this was foolish. I disagree, I lived there over twenty years and used the cruise control in everything from a 3/4 ton pickup to a Porsche C4 going downhill on that same route. What you failed to ask Adrienne was what kind of road they were using. It is I-70 with 2 to 4 lanes in each direction. The speed limit is 65 mph. If you put the car in 4th gear and set th cruise at 65 it will hold 65 except on a few short steep sections. Of course the road must be dry.
The knowledge the two of you have about car mechanics never ceases to amaze me. That being said I think you might want to keep your advice to what goes on under the hood and not how to drive.
A woman called in about driving down mountain passes with cruise control on and you made it sound like her husband was a moron for doing it.
The road between Vail and Denver is I-70 it is not some little two lane road with a 25 mph speed limit.
The back side of interstate type mountain passes goes on for miles and it is almost impossible to find a gear that will keep you at a constant speed. If you are in too high a gear you have to brake but if the gear is too low you start slowing down. By selecting a gear that will slow you slightly and setting your cruise control for the speed you want to maintain you keep a constant speed. If the hill gets steeper and you start to speed up you would do exactly the same thing you would do if you didn?t have your cruise control engaged ? step on the brake. Then guess what happens ? your cruise control shuts off.
The people who follow your advice are the ones who keep slowing down, then speeding up, etc all the way down the big hill. Driving at a safe constant speed is always better than constantly varying your speed.
You guys need to take a trip out west and do some mountain driving before giving out bad advice.
I don’t know about the Subaru, but my 2007 Dodge Caravan will automatically downshift when going down an incline to (or in an attempt to) maintain speed. From the owners manual:
To Accelerate For Passing:
Depress the accelerator as you would normally. When the
pedal is released, the vehicle will return to the set speed.
NOTE: The speed control system maintains speed up
and down hills. A slight speed change on moderate hills
Your vehicle will experience a downshift to 3rd gear
while climbing uphill or descending downhill. This
downshift to 3rd gear is necessary to maintain vehicle set
On steep hills a greater speed loss or gain may occur so
it may be preferable to drive without speed control.
You still have to use your head. If the hill is too steep, you will still go too fast. I have yet to see a cruise control that slows you down when you drive off a cliff.
Love your show!
This is exactly right. The cruise control can help maintain a steady speed, but it’s the driver’s responsibility to drive the car. When the speed drifts too high, you have to touch the brake, whether or not you had your cruise control on. You may want to manage speed with the transmission, manually if necessary, to save the brakes. And neither of my cars will keep up with traffic while climbing the passes, so I may have to change lanes. It’s a busy time, comparable in many ways to rush hour on the DC beltway. But IMHO it isn’t any more dangerous with vs. without cruise control, as long as you stay engaged. I find it easier to take one variable off my mind while I watch out front, sides, and rear, and try to anticipate the wackos.
Tom and Ray probably aren’t familiar with the expansive mountains we keep out here. I-70 rises and falls several thousand feet on the passes, but across tens of miles – which means most of the time the grade is a few percent or less, or even rising briefly in the middle of a descent. Either way, there’s plenty of justification for using your cruise control to keep up a steady 65-70mph so you don’t get run down by Yukons.