Car Advice

Reader question: should I cancel cruise control downhill?

This week we received a question from a reader about whether they should cancel cruise control when driving down a hill.

G’day, I’ve only just started driving a car with cruise control, and I want to know if I am harming my car by cancelling cruise control when going down a long steep hill and coasting instead of letting the car automatically rev up in a lower gear to stop going over the set limit. I do this and find that on steep gradients the car will coast down hill at the same speed and when I get to the bottom I flick cruise reset. I only do this when there is no slower cars in front of me.

Hi there,
You’re best off leaving the car to do its thing. Modern automatics sense gradients and automatically select lower gears. This is done so the brakes don’t overheat, and it’s easier to control the car if it has a lower gear. The cruise control is only replicating what a human drive would do. Yes, revs may be a bit higher, but that’s fine.
 
I’m a bit confused by the statement that it coasts down the hill at the same speed… if the gradient is steep the car will speed up. However, most steep gradients also have significant corners, so aren’t suitable for cruise control. There are some freeways that are quite steep, for example the approach into Adelaide.
 
Another point is that not all cruise control systems stop the vehicle exceeding the set speed, most permit overruns. In that case, you’ll need to take control yourself either by braking gently or selecting a lower gear, both of which will deactivate cruise control.
 

Robert Pepper

Robert Pepper

Robert Pepper is a motoring journalist, offroad driver trainer and photographer interested in anything with wings, sails or wheels. He is the author of four books on offroading, and owns a modified Ford Ranger PX which he uses for offroad touring. His other car is a Toyota 86 which exists purely to drive in circles on racetracks, and that's when he isn't racing his Nissan Pulsar. Visit his website: www.l2sfbc.com or follow him on Facebook https://www.facebook.com/RobertPepperJourno/ or buy his new ebook!