Nostalgia has motivated me enough to dig out a photo from my trip over there. This is my bike and I with my hosts (and pals from Edinburgh) Doug and Rosemary McKnight, who I stayed with in Boulder for a fortnight.
We are at Lake Brainard, 10,000 ft up in the Roosevelt National Forest, although it has to be qualified by the fact that Boulder is itself at 6000 ft (as is Denver). Doug has a Trek 7000, and Rosemary is on a Bridgestone MB-4, for the record.
It is an absolutely fantastic place, and the altitude makes some difference. First times out when I was climbing I would get out of the saddle to respond to inclines, then fall off at the next corner as my heart rate shot way, way, past the point where it would normally stabilise.
The Tufftrax performed admirably, bumping over logs and shuddering down mine roads made from not-very-crushed rock with no mechanical troubles at all. It doesn't look out of place in the slightest, in contrast to its owner with the sickly pallor of the Northern European, albeit with weatherbeaten cylists hands.