RV Mountain Driving
Perhaps the most white-knuckle experiences during RV mountain driving occur while descending a steep grade. The heavier the rig, the more daunting it can be. But it does not have to be if you follow a good plan.
When approaching a grade that is descending, slow to the speed, or slightly lower, that you intend to descend at prior to reaching the crest. Select a lower gear to maximize engine RPM and driveline resistance. Maintain any excess speed by short, hard applications of the service brakes. Remember, the wind resistance is now working with you, and can aid you to keep a comfortable speed.
If equipped, engage the exhaust brake or single speed Jake. Observe both speed and engine RPM during the descent and control same, if required, with short, firm service brake applications.
Tip: Get to know your speed in each gear when the engine RPM is at the optimum braking speed; for a diesel, about 90% of the maximum governed loaded speed. If you can’t always remember this speed for each gear, or to make it easier, put a small red sticker at each location on the speedometer. Select your grade descent to be one of these speeds. This will normally deliver smoother braking and possibly eliminate further downshifting.
If the engine (Diesel) RPM increases to near that listed in your engine manufacturer’s manual as being the maximum RPM during compression brake application (usually 10 to 15% higher than the governed speed), apply the service brakes firmly to bring it back to near its original speed. If, on the other hand, the engine RPM reduces near the speed that would cause an additional downshift, shut off the Pac Brake/Jake switch. Do not touch the accelerator pedal if your unit is configured to auto-select a lower gear as that will cause an upshift at this point. You can now toggle the brake switch on and off to maintain the desired road speed during the balance of the decline.
Multi-speed Jake brakes: Follow the same procedure as the single Pac Brake/Jake, except toggle the Jake higher or lower instead of the “On/Off” activation switch.
Vehicles equipped with transmission grade retarders should make the same grade crest approach. Apply the joystick retarder control at the lowest setting, increasing it as necessary.
A word of caution in the use of any compression braking. Use only when the road surface provides adequate traction. Even wet roads may not be safe for unrestricted use.
Be safe and enjoy the ride down.
Note: The operation, and or tips, herein stated, may vary or not be applicable to all vehicles configurations. Always refer to the directions as outlined in the O.E.M. operator’s manual for your specific vehicle.