Ethan Hayter was going great guns in the time trial at the UCI Road World Championships, but his hopes of a medal or even the rainbow jersey were ended by a mechanical issue.
The Briton, who was at the time fastest through the first intermediate checkpoint, saw his chain drop off towards the end of the first lap of the Wollongong circuit.
Hayter was trying to shift up into the big ring as he made his way along the coastal road with 15.7km ridden and 18.5km remaining in Sunday's time trial.
The chain slipped and, unable to tease it back on, Hayter had to stop for a bike change, throwing his broken one against the roadside barriers in frustration.
He remounted and re-focused himself in impressive fashion to salvage fourth place, but was left wonder what might have been.
"I"m slightly disappointed," Hayter said at the finish ."But fourth place is still pretty good isn't it... But yeah, slightly disappointed."
Hayter attributed the cause of the mishap to his set-up, with a new Pinarello time trial bike and mismatched drivetrain components.
"As I was changing chainring... we have this new bike... it's that Shimano don't make chainring shifters on the new gears," Hayter said.
"I was trying to change chainring and it wasn't quite shifting so I pressed it again, and it dropped off, and there was no way to get it back on without the chairing shifter.
"So I had to swap bikes; it was the fastest thing to do that time. I think I limited my losses quite well from that point."
Hayter was using an unbranded 60t chainring rather than a Shimano 58t chainring, perhaps for aerodynamic gains and a slightly bigger gear. According to Cyclingtips he was also using Shimano’s single-button shifters with a semi-automated Synchro shift.
That chainring combination perhaps affected the crispness of his gear changes and sparked the chain to drop. The semi-automated Synchro shift, meanwhile, meant that the front derailleur didn't have a direct manual shift command, but rather shifted automatically based on pre-configured settings determined by the overall gear ratio. As a result there was nothing Hayter could do to resolve the matter manually - he had to change bikes.
The next problem was that Hayter's spare bike didn't match his original.
"The bike handles a bit differently with the different brakes and the different handlebars but think I did alright in the circumstances," he added.
Indeed, Hayter, who had been faster than the eventual winner Tobias Foss at the first checkpoint, rode a strong second lap to finish fourth at 40 seconds, with the final podium position of Remco Evenepoel just 30 seconds away.
It's hard to calculate exactly how much time was lost to the bike change, which will hardly put Hayter's mind to rest as he contemplates whether it could have cost him a podium place.
"I have no idea," he said. "It would have been nice to try. 40 seconds is quite a lot to win but it could have been close.
"There wasn't really any pressure - no one had me down as a favourite, apart from my teammate Luke Plapp. But it was an opportunity. Some guys were tired. Foss was not a surprise to me but maybe to the media he is. Fortunately the World Championships are every year."
In any case, Hayter's performance will give him confidence as he prepares to lead the line for Britain in next Sunday's road race, especially after having to leave the recent Vuelta a España with COVID-19.
"It was really a shame to leave Vuelta. I didn't get to show myself, then had to sit on sofa and not talk to anyone for a week. But I got back into it and came into here fresher maybe," he said.
"Hopefully today will be good training effort ahead of the road race next week, plus a bit of a recon of the course."
