FWIW, I trained all winter and early Spring before my 50th birthday on June 19th. This was 15 yrs. ago. Rode my rollers and rode hard in May and early June. I was determined that I would do a 20 mi. route (one of my TT rides) at 20 mph. This was on my steel framed & chromed MAZA TSX bike with Athena gruppo. Not the lightest but not bad "back in the day." The day came and the weather was just right. No warm up just TT-ing it all the way. Hit the traffic lights through the Univ. of Conn. just right. At the end of the ride I checked the computer did some math and clocked 19.98 mph. I called it good and had a beer. Turning 50 was a great day for me.