In prep for my 11th century - for the first time on an 29er (ungeared), a road biker joined me for the first 5 miles or so, and to keep up I was averaging around 10-12 mph, although that was pretty slow for him. Btw, that’s my usual cruising speed on my 36er!
I handed him my gopro so he could film and use his GPS to see what top speed I could get. Into a bit of a headwind I hit 15 mph the first time, but forgot to hit record! Second time hit 14.8. Based on the fact that with my particular 29er tire and with weight on the uni, the distance traveled per rev is 7.5 feet. 15 mph equals 22 feet per second, so I was very close to 3 revs per second, which was scary and exhilarating at the same time! One false move and they’d be scraping me off the bike path.
Here’s a short video: