How to Drive On A Steep Hill

If there's one truism that applies to any driving technique, it's: always be prepared for anything. Hills present a few challenges when driving both up and down them. This is especially true when it comes to cornering and braking, both of which introduce additional forces that affect the car's weight transfer and balance.

Driving Uphill

  • Downshift into one gear down from your cruising gear for anything up to a 3-percent grade, and downshift another gear for every 3 percent over that. On a five-speed car, you'd take a 3-percent grade in fourth, a 6-percent grade in fifth and a 9-percent grade in third. Accelerate up the hill until your engine reaches about 1,000 to 1,500 rpm above its cruise rpm. Any higher than that and you risk overheating the engine; drop down a gear, and you risk "lugging" the engine or overheating the transmission.

  • Let off the gas to take a turn if you have a front-wheel-drive car, and maintain a steady throttle (within safe speed limits) for a rear-wheel-drive car. Going up a hill transfers a great deal of your car's weight to the rear axle, reducing traction to the front tires and thus steering response. Letting off the gas on a FWD car will reduce stress on the front tires and allow you to take the turn safely; maintaining throttle on a RWD car will keep its handling fairly neutral.

  • Let off the gas as you crest the hill and be prepared for a brief reduction in steering response. Your car assumes an upward trajectory while going up the hill, which means that once the hill goes away, the car's inertia will continue to carry it upward. Until the car settles down, the steering will start to feel light and you'll briefly lose a bit of control over the steering.

Driving Downhill

  • Maintain your climbing gear, or drop down by one or more gears. What you should do here is dependent on the vehicle's weight and engine type, and the grade. Gravity will pull your car downhill, causing it to accelerate. If you don't control the acceleration, the car or truck will accelerate out of control and turn into a "runaway." Heavy vehicles with lower-compression gasoline engines and automatic transmissions going down steep grades will require more downshifting. Light, high-compression gas- or diesel-engined, manual-transmission vehicles on shallow grades require less downshifting.

  • Modulate speed using primarily engine braking, but tap the brakes as necessary to keep engine speed at a safe rpm and to keep your vehicle within 5 mph of your intended speed. Decelerate to a safe speed well before entering any turn. The extra weight on your front axle will make your vehicle prone to oversteering or tail-sliding; hitting the brakes as you enter a turn -- known as "trail braking -- will transfer even more weight to the fronts, inducing a possibly dangerous amount of oversteer (skid).

  • Come to a stop by pressing firmly on the brake pedal, but don't stab it as though panic-stopping. Too little pressure for too long a time, and you risk overheating the brakes, boiling the fluid and glazing the pads. Too much, and your already-hot brakes may reach their failure point even faster. Either way, the end result is gradual to complete brake-system failure. Do not set your parking brake immediately after stopping; brake pads have a way of welding themselves to glowing-hot rotors.