In reply to Frank4short: Just to reference my previous post in regard to some of the stuff others have said.
Tommy Goodwin still to this day (73 years later) holds the world record for the most mileage cycled in a year, 75,065 miles (120,805 km), and the quickest ever to cycle 100,000 miles in 500 days. That's an average of over 200 miles a day, every day, over a year and a half,
SOLO. In a time before carbon bikes, fancy drive-trains, basically any of the advantages of the modern bicycle, or modern training regimes or nutritional information. These are both records which are unlikely to be ever repeated again let alone beaten by any significant margin.
Steve Redgrave may be Britain's greatest ever Olympian but all of his medals were as a part of a team/pair so not done on his own. And it's unlikely with time his achievement won't be equalled or bettered.