We drove CO 139 today going north from Grand Junction to Rangeley in a 33' 5th wheel pulled by a Ford F350 7.3 litre engine. It was a long, slow climb to the pass. But what really got us was the steep downhill grade. We put the engine in 1st gear and immediately got up to 40 mph...top speed for 1st gear. So we had to use the brakes. A lot.
Ended up pulling off the side of the road when we smelled burning. Got out and smoke was coming from the left rear wheel on the truck. All four truck wheels were blazing hot.
We sat for over an hour waiting for them to cool off. When we continued our descent we had passed the worst of it and barely used our brakes the rest of the way. The road from that point (where we had stopped) follows gradual valleys down to Rangeley.
We were rather freaked out by the smoking brakes!