I learned how to go real fast today. All you need are 2 mongrel dogs nipping at your back wheel!!
I was mid ride, just after the biggest hill of the day, and had slowed to 10mph on the flat after the hill. Then, out of the corner of my eye two 50-60lb dogs running at me. The next time I looked down, I was going 30mph!!! (no it was not downhill) I kept it up for maybe 30 sec and then sucked wind