Mountain Grades & Brake Fade

On a long downgrade, gravity keeps pushing a heavy truck faster. If you rely on the service brakes to hold your speed, they heat up, lose their grip (brake fade) and can fail completely. The way down a mountain is decided at the top: the right gear, the right speed and the right braking technique.

• Truck drivers
• Bus drivers

Before the descent

• Watch for grade warning signs and stop at brake check areas when provided
• Know your weight. Heavier loads need lower gears and slower speeds
• Check brakes are in adjustment and working; check air pressure
• Choose a safe speed for the weight, grade, curves and weather
• Shift down to a low gear before you start down. A common guide is the same gear (or lower) you’d need to climb the grade
• Turn on the engine brake (retarder) if conditions allow

Snub braking

Use the engine brake and low gear to do most of the work, and the service brakes only to snub (bring down) your speed:

1. Pick a safe speed.
2. When the truck reaches about 5 mph over that speed, apply the brakes firmly enough to feel a definite slowdown.
3. When the speed is about 5 mph below the safe speed, release the brakes.
4. Repeat. The brakes get time to cool between applications.

Light, constant pressure on the brakes (“riding the brakes”) is what causes them to overheat.

Brake fade

• Signs: you have to press harder to get the same braking, a burning smell, smoke from the wheels.
• Brakes out of adjustment fade sooner, because the others do more of the work.
• If you notice fade, slow down while you still can and pull off to let the brakes cool.

Runaway truck ramps

Escape ramps are deep gravel beds or uphill lanes that stop a truck that has lost its brakes. If your brakes fail, use the ramp. It can save your life and others’. Know where they are on your route.

Don’ts

• Don’t coast in neutral or with the clutch in. You lose engine braking and may not get back into gear.
• Don’t try to downshift halfway down a steep grade at too high a speed; you may not be able to get into gear.
• Don’t follow other vehicles closely down grades.
• Don’t use the engine brake on icy or slick roads if your company or the manufacturer says not to; it can cause a skid.

Going up

Climbing, a loaded truck slows down a lot. Use the slow-vehicle or truck lane, turn on your flashers if you’re much slower than traffic, and watch temperatures so the engine doesn’t overheat.

Last updated: October 1, 2026