There is a bit of RV lore as to the dangers of driving the Cabot Trail in the Cape Breton Highlands region of Nova Scotia, and for the most part it’s unfounded. We drove our New Aire 3341 on the Cabot Trail in August 2019 to get to and travel between the east side Broad Cove Campground and the west side Cheticamp Campground. The Cabot Trail is like many secondary roads in mountainous areas: scenic, and steep and twisty, although quite manageable if you take it slow. That is until I saw a sign proclaiming a 13% hill. To most folks a 13% hill is no different from an 8% hill, just apply a little more throttle. But to us RVers, 13% may as well be rock climbing territory. I entered the hill at 45 mph already downshifted to 3rd gear and with the pedal to the metal. In less than 2 minutes we were going 13 mph in first gear. I kid you not I actually thought we weren’t going to make it. Luckily the ISB engine had just enough torque to maintain 13 mph the rest of the way.

Note the small 13% grade for 3 kilometers sign

The Cabot Trail has twisty turny sections

Ah, the ISB engine. 6.7 liters, 360 HP, 800 lb-ft of torque. Perfect for a pickup truck that weighs 10,000 pounds and pulls up to a 10,000 pound trailer. Not so ideal for a 35,000 pound RV towing a 5,000 pound SUV. In addition, the intensity of the engine brake (which is used to control a diesel motorhome’s speed going down a long, steep hill) is a function of horsepower; meaning, a smaller engine will provide less engine braking than a larger engine.

This was made clear when we started to go down the other side (also 13%), when the engine brake plus downshifting plus “surge” braking were not sufficient to descend safely. In over 100,000 miles of driving large class A motorhomes down many long grades in the Rockies, the Sierra Nevadas, the Cascades, the Smokies, etc. I’ve always felt 100% in control. Not so in the ISB equipped Newmar New Aire 3341 on the Cabot Trail. The first sign of trouble was the unmistakable smell of burning brakes, following by visible smoke emanating from the wheels, culminating in a spongy brake pedal. Luckily the road leveled out just enough with a large pull out to stop and let the brakes cool off before continuing the descent.

We stopped at a large pull out to allow our brakes to cool

Construction section on the Cabot Trail

What could I have done different on this descent to avoid brake loss? I honestly don’t know. My GPS warned about the steep grade ahead of time, so I entered the hill going only 20 mph in second gear with the engine brake on. I didn’t ride the brakes; I applied them to reduce speed from 30 to around 20, then let off for a few seconds to help cooling. The problem is that it took much longer to reduce speed from 30 to 20 than it did for gravity to increase speed from 20 to 30. After approximately 10 rounds of this on-off brake use, I had no more brakes. Perhaps I should have started downhill going 10 mph in first gear? In any case, I’m 100% confident our considerably heavier (by 15,000 pounds) Essex would have handled this hill with zero loss of brakes due to considerably greater HP (600 vs. 360) and therefore considerably more help from the engine brake.