Wednesday, March 29, 2023



Prepare for steep grades

By Russ and Tiña De Maris

steep grade copyFor some of us, heading out to the amusement park and taking a ride on the roller coaster is just plain fun. When ‘the bottom drops out’ and you’re screaming downhill, the adrenaline rushes — well, it’s really something. But the last place you want to ride a roller coaster is when you’re behind the wheel of your RV. Hitting a steep grade unprepared is anything but fun – for too many, it’s deadly. Are you ready for steep grades?

Not all steep grades are down – and your rig needs to be ready for the uphill climb, too. Ensure your cooling system is up to it. Does your engine coolant need a change-out? How about that radiator? Clear of dirt, bugs or other obstructions? Belts and hoses in good shape? OK, let’s look at the “flip side.” Well, we hope it’s not literally a flip side!

For the down-hilling side, brakes are the major concern. Brake pads (or shoes) in good shape? A quick look at the brake fluid reservoir will give a fast indicator for tow rigs and motorhomes. If the fluid is low, there’s a reason. Either you have a system leak, which needs to be addressed immediately, or your brake shoes or pads are wearing. Either way, check it out before heading off on an RV trip.

On towables, a brake system check includes pulling the wheels and inspecting the brake shoes. It’s a good time to repack the wheel bearings, too, which is a job that should be done each year. Reset the adjustment of the shoes so that your brakes will be ready to brake! Next, check out the upstairs – that means, the one between our ears.

Do you understand road grade signs? It’s more than the silhouette of a big truck pointing down a slant. We’re talking about grade signs that indicate percentage of grade. Some new to RVing don’t yet have a grasp. Put simply, a grade sign indicates is how many feet of fall there is in the roadway over a given distance. For example, a 5 percent grade sign means for every 100 feet of roadway, there’s an average drop of five feet. You quickly grasp that the bigger the grade percentage, the steeper the drop, or climb.

Here’s an important corollary: The longer the grade, the more inherent danger. A real steep hill in downtown Seattle could easily go into double digits of grade, but if it’s only a block or two in length, it’s not nearly as scary as a 6 or 7 percent grade that runs for miles.

Safely tackling steep grades means learning to go slow. Going up hill, you may be able to go fast, but you’re asking a lot from your engine and cooling system. Steep climbs — especially in warm weather — are better made in the cool of the morning. Pulling a steep grade in warm weather is taxing to your cooling system. Keep a close eye on your temperature gauges – engine and transmission (if you’re so equipped). If engine temps begin to climb, shut down your air conditioner. If they continue to rise, roll down your windows and turn on the heater. Yep, the additional heat put off by your heater may be enough to counter a rise in engine temperature. If that doesn’t cut it, PULL OVER. Set your parking brake; don’t shut off your engine, rather increase the engine revs above a normal idle to help cool down the engine. And be sure to pull over before you hit a “red line” temperature!

Before you hit the summit of a climb, check your brakes. Much better to let the upgrade slow and stop you if your brakes are “gone” than to find out they’re gone when you’re headed downhill. And here’s the old trucker’s rule on gearing: Whatever gear you needed to climb the hill is likely the one you’ll need to go down the other side. In some cases with modern drive trains, you may actually need a gear lower.

Engine compression is your friend — the less you need to step on the brakes, the better off you are. Diesel engines have comparatively less “compression braking” ability than a gas engine, so you may need to gear down even more. And be sure to “kick down” to the lower gear BEFORE you need it, else you might not be able to gear down later when your speed is too high.

Use your brakes if you need to, by all means, but keep “geared down” enough so that you can stay off the brakes and allow them to cool between applications. You can come down the hill “too slowly” time after time, but come down the hill “too fast” and you may do it only once! And be sure to slow BEFORE coming into a curve, rather than trying to slow IN the curve. Recommended speed signs for curves are based on a passenger car, not a big RV. So take the curve slower than the posted sign, and begin to accelerate in the curve. Why accelerate in a curve? It’s a matter of physics. Your rig will generally continue to go in the direction it’s going until an outside force acts on it. As you hit a curve, there’s a sideways force that will try and pull you one direction or the other. Giving a little acceleration will help compensate for that side pull, and keep you headed forward.

What if you get into trouble? Let’s say you encounter “brake fade.” You hit the brakes, and they aren’t there. Get off the throttle, and turn off the cruise control. If you haven’t already kicked down in gear, do so immediately. PUMP the brake pedal—you may be able to get a bit of pressure built up to help you slow down. Try using your parking brake. This will likely have very slow results, but it may yield some amount of brake effect. Warn traffic ahead by blowing your horn. If there’s a “runaway truck” ramp, by all means, use it. And if all else fails, use the Jersey barrier to scuff off speed. Most are designed to rub against your tires (as opposed to your paint) to help slow you down. Scraping the side of your rig on a guardrail is better than going over the edge, so it’s a possible last resort.

See you on the other side of the hill!



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Jim & Janey Price
6 years ago

Hi Russ & Tina
Good article, especially for a newbie like me who has yet to try driving in the foothills.

I would have liked some discussion about how the Tow/Haul function works and how it could help in these scenarios. It would be especially valuable since, when we bought our class A new, the tech giving us our fam didn’t know what that feature was or did when I asked. Can you clue me in?

Sharon Baron
6 years ago

Scary thinking about a run away rig.
I will look into those dimpled rotors that Bill suggested.

6 years ago

I have a 12,000 lb rig, class C 28ft and the front disk brakes were a joke. Replaced the rotors with dimpled and slotted and the difference was dramatic. Was extra money but nothing scarier than not being able to brake. Your advice is right on. Many times we have to turn on the heater to keep engine heat down…it is only for a short time but the engine is happy we did.

Gardner Yeaw
6 years ago

You should mention that air brakes are very different. Pumping them will deplete your air supply making matters worse.

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