“I would like to see the Tour de France only allow riders to ride one bike the entire tour,” he said. “Do their own maintenance, change their own flats, the way that normal
people have to. Racing would have a positive trickle-down effect, instead of the way it is now. Bikes would be better, they’d be safer, and they would last longer. And the races themselves wouldn’t be less interesting at all.” (Grant Petersen)
In fact, that’s the way the early decades of the Tour de France were run. You could not accept any external help for your bike. That’s why you see riders with spare tires/tubes
around their shoulders.
From
1922 Tour de France by BikeRaceInfo (16th TdF):
“Hector Heusghem was leading the Tour but in stage 13 he was given a 1-hour penalty for changing bikes after a crash. That gave the Tour to Belgian Firmin Lambot.”