With around 1.2 kilometres to race to the finish line at Chalet Reynard, a motorbike braked to avoid fans crowding the road on the famous ascent. Richie Porte (BMC Racing) and Bauke Mollema (Trek-Segafredo) crashed along with Froome.
Porte stopped and repaired his bike. Mollema rode ahead to finish at 5-05 minutes behind Thomas De Gendt (Lotto-Soudal), who won from an escape.
But Froome, with his bike broken, was forced to run up the road for 50 seconds while he waited for cars to catch up with a replacement bike.
Froome, who started the stage in the yellow jersey, finished 25th at 6-40. In the provisional results, he lost the race lead to Adam Yates (Orica-BikeExchange), who passed while the Sky rider floundered.
The race jury, however, overturned the provisional classification to not only preserve Froome’s lead, but extend it.
“I think it was a fair decision, and I want to thank the jury and the organization,” Froome said after hearing the race’s decision. “It was the right decision.”
When Froome raced up Ventoux in 2013 to secure his first Tour title, fans nearly caused incidents. The barren climb, where Tom Simpson died, had to be cut short by six kilometres this year due to high 100kph winds at the top. Instead, the race finished at Chalet Reynard after 9.7 kilometres.
“Ventoux is full of surprises,” Froome added.
“About 1.2 kilometres to go, the motorbike slammed on its brakes. The road was blocked in front, the three of us just ran into the motorbike and another motorbike ploughed into me, breaking my frame,” Froome added.
“I just started running. I knew the car was stuck behind was five minutes behind.”
Many viewers have criticised the lack of crowd barriers by the roadside, but race director Christian Prudhomme said that organiser ASO was unable to use barriers in the final kilometres because of the strong winds that ripped through Provence.
“We took an exceptional decision because of this exceptional situation, an incident that might have never happened before in 100 years,” Prudhomme said.
“There was a considerable amount of fans, with some exceptional people but others who were more excited. There will be an investigation to find out why the TV motorbike was blocked and the riders fell.
“As a consequence, the race jury decided to give Porte and Froome, and behind them Quintana and Valverde, the same time as the other riders who were not, or less hampered by the incident.”
The new stage classification had Froome still in 25th – but at 5-05 minutes behind, the same time as Mollema and 19 seconds ahead of the Yates group. His lead now stands at 47 seconds on Yates, 54 seconds on Quintana and 56 seconds on Mollema.
General classification after stage 12 (provisional)
1. Chris Froome (GBr) Team Sky in 57-11-33
2. Adam Yates (GBr) Orica-BikeExchange at 47 secs
3. Bauke Mollema (Ned) Trek-Segafredo at 56 secs
4. Nairo Quintana (Col) Movistar at 1-01
5. Romain Bardet (Fra) Ag2r at 1-15
6. Alejandro Valverde (Esp) Movistar at 1-39
7. Tejay van Garderen (USA) BMC Racing at 1-44
8. Fabio Aru (Ita) Astana at 1-54
9. Daniel Martin (Irl) Etixx-QuickStep at 1-56
10. Joaquim Rodriguez (Esp) Katusha at 2-11