Fox has a list of most unbreakable sports records here:
Of course none are cycling records. Also they have a few that are not even the most unbreakable for the individual they list. At #5 is Wilt Chamberlains 100 point game. Some day this will fall. Trends change and eventually high scoring games will return and some game will go into 6 or 7 overtimes. May take a long long time. On the other hand Wilts average minutes per game will not fall at 51 or 52 minutes a game (Yea I know regulation is 48 minutes). For an entire season Wilt played every minute of every game, including all overtime.
At # 2 is Jerry rice for total receiving yardage. This may never fall. Or it might. The trend is more regular season games. Add 2 more per year (with 2 less preseason games) and perhaps someone will last long enough to pass this record. But Rice's recort for most consecutive games with a catch is a different story. It is more games than any other wide receiver has in his career.
But the reason for starting this thread is to pose the question:
What cycling records are unbreakable? Feel free to phrase the record in the terms that make it hardest to break.