Something interesting happened on my evening commute yesterday. I almost never get passed by a bike on my commute, not that I try to race everyone I see. If someone does pass me, I usually just try to follow them for a while to see if I can maintain their pace. I only pass back if someone is actually slowing me down. Anyway, I was coming down a slight grade, not pushing super hard, maybe 19mph, when this guy on an xtracycle loaded with gear blasts past me. Intrigued, I jumped anaerobic and followed him for the next mile. I think we averaged about 26mph. In my commute gear, that's about my limit. I know we slowed down significantly to take a rr track, and the lowest I saw on my speedo was 21mph. Just as I was about to blow up, my route takes a sharp right turn. He took it too, and had to slow down significantly to make it.

Me: "That was a pretty zesty pace."
Him: "I'm cheating."
Me: "What? How?"
He points to some kind of battery powered motor pushing a second chain ring on his left side.
Him: "This thing puts out about 200 watts."

We went on to have an interesting talk for the next mile or so until we split up.