danemayer
Well-known member
We drove thru Denver yesterday on our way to Breckenridge, CO. That took us west on I-70 climbing from 5000 feet in Denver to 12,000 feet at the Eisenhour tunnel, followed by a very steep descent for about 8 miles or so into Silverthorne. We're towing a pretty fully loaded Landmark Rushmore (39 feet). I haven't weighed, but I'd guess we're towing 15,000+.
I mostly used the cruise control and let it manage the transmission. Going up the mountain was effortless. I think we were in 5th and 6th gear almost the whole climb. 45-50 MPH on the winding areas, and 55 on the straighter sections.
Going downhill I set the cruise control at 35 (to comply with the signs for vehicles > 26,000 GVWR), enabled the exhaust brake (which helps a little), and went down from Eisenhour tunnel to Silverthorne at about 2500 RPM. No brakes needed at all. (BTW, I've always wondered about the runaway truck ramps - we saw a truck on one of them this trip).
Earlier in the trip, going north on I-25 from New Mexico, I found the cruise control managed downhill speed pretty well to 55. There were a few times it shifted down a couple of gears (4th?) and the engine was up to 4000 RPM for a brief period.
This is our first diesel/5th wheel, so I don't have a history of comparative towing, but after this, I'd recommend the GMC 3500 Diesel to anyone towing in the mountains.
I mostly used the cruise control and let it manage the transmission. Going up the mountain was effortless. I think we were in 5th and 6th gear almost the whole climb. 45-50 MPH on the winding areas, and 55 on the straighter sections.
Going downhill I set the cruise control at 35 (to comply with the signs for vehicles > 26,000 GVWR), enabled the exhaust brake (which helps a little), and went down from Eisenhour tunnel to Silverthorne at about 2500 RPM. No brakes needed at all. (BTW, I've always wondered about the runaway truck ramps - we saw a truck on one of them this trip).
Earlier in the trip, going north on I-25 from New Mexico, I found the cruise control managed downhill speed pretty well to 55. There were a few times it shifted down a couple of gears (4th?) and the engine was up to 4000 RPM for a brief period.
This is our first diesel/5th wheel, so I don't have a history of comparative towing, but after this, I'd recommend the GMC 3500 Diesel to anyone towing in the mountains.