After World War Two, older riders were relatively commonplace, often having lost a chunk of their 20s or 30s to the fighting. Decorated RAF bomber pilot Les Graham was one such, turning 38 in 1949, when he took the inaugural World Championship. He was killed on the Isle of Man the following June. Giacomo Agostini, a 15-time champion, had faded from prominence when he retired aged 35 in 1977.
But in recent years a cult of youth means starting racing aged ten or even younger, leading to a younger average age, younger champions, and earlier retirement.
The trend, however, doesn’t make it any easier for Rossi to know when to stop. Only two champions have managed to walk away while still at the top, taking a clear and logical decision. Legendary American triple champion Kenny Roberts was 31 when he quit, right after losing the 1984 World Championship to 21-year-old Freddie Spencer. Double champion Casey Stoner also quit abruptly, aged only 27.
A few other champions simply faded away. but most had their careers forcibly terminated, either by a major injury, like Wayne Rainey and Mick Doohan, or by an accumulation of them, like Wayne Gardner and Kevin Schwantz.
It is these cases as much as the admirable persistence of Rossi that illustrate how difficult it is to quit. It is equally difficult for Yamaha to decide whether to continue to support the sponsor-friendly and wildly popular Italian. Rossi says it will depend on how competitive he feels in the early races.
So what does he face in 2018, as he chases Ago’s all-time record? At early tests, he and Yamaha team-mate Maverick Vinales were troubled by a continuation of sundry issues that blighted 2017, while last year’s rookie revelation Johann Zarco was irritatingly fast on a 2016 Yamaha.