My personal top speed is 57.5 MPH. But that was under ideal conditions. Touring bike, consistent tail wind, straight road with good pavement. I didn't realize how fast I was going until I got to the bottom and checked my top speed.

It was on this road:



I've since had a serious crash, albeit at "only" about 24 MPH. Lemme tell you ... asphalt hurts. And my crash was due to an equipment failure ... a blown (probably incorrectly installed) tire.

I now keep my top speed at between 30-35 MPH, even under ideal conditions. Any faster, and I remember my earlier crash and the fact that the energy dissipated in a crash goes up with the square of my speed.