Alex Porter's handlebar snapped under him as the Australian Team Pursuit challenge was one minute into the race.

Porter was fortunate that he was at the back of the foursome during the opening lap when the breakaway occurred, so he did not involve his teammates, but the breakaway was due to equipment failure, not athlete error. This allowed Australia to make a second start, but they could only manage fifth place with a time of 3:48.448, and their hopes of competing for the bronze medal faded.

Denmark dominated the qualifying round (open in new tab), posting the fastest time of 3:45.014

The cause of Australia's crash was the integral base bar and stem, which broke at the joint where the stem area transitions to the outward facing base bar.

Initially, it appeared as if the cockpit in question was the stock standard carbon base bar that Argon 18 sold with their Electron Pro track bikes. However, upon further inspection, it appears that the cockpit is actually a bastion base bar that was 3D printed from titanium to closely mimic the same design.

According to a report in Cycling Weekly (opens in new tab), the base bar was removed from Bastion's website after Porter crashed at the Izu Velodrome.

Bastion is a frame builder and manufacturer of 3D printed titanium parts and typically uses this technology for frame lugs. In late 2019, however, the company announced a partnership (opens in new tab) with Cycling Australia, tasked with providing custom-molded handlebars and aero extensions for the team's track bikes.

Comparing images of the broken cockpit wreckage with images of the Bastion base bar, there are slight differences that confirm it is not the carbon fiber base bar supplied by Argon 18.

The top edge is slightly concave as the sides of the stem area protrude outward to form the base bar. This concave detail is also seen in the 3D printed bastion base bar. The Argon 18 base bar, on the other hand, is convex, rounding outward from above toward the cockpit handlebar area.

A closer look at the bastion base bar reveals four mounting points hidden under a cover at the top.

As shown in the image above, the failure point occurs very close (if not directly in front) of the bolt hole in the front, suggesting that over-tightening of this bolt was the cause of the failure.