Random Fourteener Fact: Mount Bierstadt is located just south of Georgetown, Colorado.
Mt. Bierstadt is close to Denver and easy to climb. There's no exposure, no route finding (you can basically see the top from parking lot to summit), and a very well-maintained trail (ignore the old-timers outdated warnings about the dreaded willows at the bottom - there's an elevated wooden pathway there now). So, it can be crowded on summer weekends, with a wide assortment of ages, shapes, and speeds. Fastest Known Time efforts would be best attempted on a blustery September weekday. If you are trying to make good time, there's the temptation to simply ignore the trail and go straightline at the summit, but in area this heavily traveled, you'd be contributing to serious erosion.
Karl Kelman climbed Mt. Bierstadt in 1983, using the straight line approach (I was, I believe, the only person on the mountain that day, so erosion from a few footprints didn't seem like an eco-disaster). My timing was imprecise, and my recollection of that timing dim, but I think it was about one hour up, and 30 minutes down.
Karl returned to Bierstadt on Saturday, July 26th, 2014, and managed only 1:20 up and 1:37 down, with human density approaching the Disneyland level. I stayed on-piste in an effort to maintain good citizenship. The phrase "On your left!" was repeated approximately 500 times. Getting off the summit through a very short boulder field with a huge crowd made for very slow going. It's much easier to pass going uphill. The average pace of the crowd is slow, I passed approximately 1,000 people (estimate based on cars parked at the trailhead), and was passed by one. And was going at less than half the pace of an Anton Krupicka or Killian Jornet. Bierstadt is fundamentally like a European Vertical Kilometer race, which the winners complete in about 30 minutes on the fastest courses.
I was able to maintain a reasonable running pace on the initial downhill section, and continued running (when not waiting for passing opportunities) for about the first 1,000 vertical feet on the uphill side. The average grade gets considerably steeper from there, and I was slowed to a walk, except for brief moments of jogging on flatter sections. The final uphill section through a mild boulder field is combination of route finding and traffic management.
Downhill was a mix of waiting, walking and jogging. A bad fall running at Dawson Butte that required stitches had briefly tempered my enthusiasm for pushing too hard downhill. My habitual Hoka One One running shoes are great on a smooth surface downhill, but their height and bulk can be tricky in boulderfields, rocks, and uneven surfaces.