A distressed driver recently called to report that smoke was pouring from his Newell’s wheel wells. Descending a long grade had given his coach a bad—but avoidable—case of “hot wheels.” His wheels weren’t ruined. But they could have been. Following the tips below will help prevent hot wheels and will also help ensure that your trip down a mountain is as safe and pleasurable as the trip up!
1. Use your Jacobs engine brake (“Jake”) as much as possible. The Jake brake is controlled by the OFF/ON and HIGH/LOW switches located on the driver-side arm panel. The OFF/ON must be ON for the Jake to work. It then works automatically when the throttle is lifted. The exhaust valves in the engine cylinders stay closed after the compression cycle, and the air compression in the cylinders slows the vehicle.
2. To maximize your engine’s braking power, turn the Jake ON and the HIGH/LOW switch to HIGH. This engages all six cylinders. If this slows you too much, switch to LOW, and your Jake will work on four cylinders instead of six.
3. Even with the engine brake working and both switches on, you might need to downshift on steep grades. Start your descent in the gear you used to climb the hill, then fine-tune your gear and engine-brake selection based on how well the engine brake is holding your descent speed. If you select a gear that allows you to adjust your speed by switching between the HIGH and LOW engine-brake positions, you will rarely, if ever, need to use your air brakes during a descent.
NOTE: When you downshift to increase engine braking, don’t worry about over-revving the engine. The transmission automatically upshifts at approximately 2,400 RPM.
4. If you must use your air brakes, DON’T pump them or apply steady pressure during a descent. Instead, apply your brakes just hard enough to feel a definite slowdown. When you’ve slowed to about 5 mph below your safe speed, release the brakes. If you’re in the correct gear, this should last for about three seconds. When you’ve accelerated again to your safe speed, repeat the process. If you must do this more than twice per minute, downshift to slow down. (See Tip 3.) Again, don’t worry about over-revving the engine. The transmission automatically upshifts at about 2,400 RPM.
5. If you’ve used your air brakes during a descent, and they’re “smokin’ hot,” DON’T immediately park at the bottom of the grade. Doing so can damage your wheels, rotors and pads. Instead, drive on for a few miles so air keeps flowing over the wheels, rotors and pads and allows the brakes to cool.
NOTE: If the Alcoa label near the outside rim of your stock aluminum wheels has blackened or blistered, or the blue dot on the label has turned to a reddish color, your wheels may have overheated. We recommend that you have the wheels and brakes inspected by a professional.
Newell V.P. of Customer Service