Mike from Irvine, CA on 10/31/2022 10:11:13 AM:
I would recommend a mountain bike or cx/gravel bike. I have done it twice on mountain bikes with XC tires. The surface is hard packed and very fast. I would say whatever distance you are comfortable with on the road would be similar on the trail. My first time I did it over 2 days (staying the night in Hill City). I was bored to tears. Got done riding before lunch, and there was NOTHING to do in Hill City. The next time I did it all in one day, and it wasn't bad at all. Both times I have gone north to south. If you can do a century on the road you'll be fine doing it all in one day. It's also easier to do in one day since you don't have to pack gear for overnights.