IDK. Depends on my mood. Last year I drafted an elderly woman at 20 mph for a few miles on a slight uphill rail trail. Asked her questions about her bike so she would think I was interested in the bike, and not a stalker, when really all I wanted was a free pull. Went a little faster than the usual 18 mph with less effort. Had to keep an eye on accelerations, because those things go from a stop like a bat out of hell, and it's easy to get dropped if you aren't attentive. Bet she would have struggled to ride at 12 mph on a bike, given her age and appearance.