Anyone who watched Sunday's ninth Tour de France stage will have felt a pang of empathy for Tom Pidcock as, heading downhill towards a potential breakaway victory, a gear change was followed by pedals spinning uselessly, rather than with any kind of resistance.After all, who has fluffed a gear change, or perhaps crashed into the small ring when it wasn't needed, and been left spinning out?In Pidcock's case, though, his SRAM shifter had apparently stopped working, rather than there being any mistake on his part. Most onlookers drew the conclusion that something had malfunctioned. However, according to the team, a piece of bitumen had wedged itself behind the shifter, preventing him from changing gear.Incredibly perhaps, given the frustrated kicking the British rider wrought upon his rear mech, presumably believing it was jammed, it continued to work using the shift lever's upper 'bonus' buttons, located on the lever hoods. Unfortunately, these weren't ideally placed for a sprint finish and Pidcock finished a disappointed third.It would be easy to assume that the team's explanation especially as it didn't come until later in the day was a carefully constructed piece of face-saving, with the real issue some kind of team oversight, such as a run-down shifter battery. Or perhaps a straightforward malfunction.However, Glen Whittington of UK manufacturer Eight Bike suggests the bitumen explanation is far from impossible because a very similar thing happened to him."If something gets wedged in behind a bit of grit, a bit of clay, something like that, then yeah, it just stops that one button from working," he told Cycling Weekly. "Actually, it's also a benefit of SRAM, that you actually do have the option then to carry on using the [bonus] button on the top."Detail showing a SRAM bonus button on the lever hood (Image credit: Anne-Marije Rook)The bonus button is a feature of SRAM Red and Force AXS levers a tiny square button on the inside top of each lever hood, facilitating gear changing when in the hoods. And it doesn't work if the lever battery runs flat, which nullifies any theory about that being the case."If the coin cell battery was low, the button on the top wouldn't work either," Whittington says. So if the button on the top is working as it was at the end, then the coin cell is up to date. But that's the kind of thing that they would check on the [SRAM] app pretty regularly, anyway. Especially with someone like him. At that level, they're going to be checking that on a daily basis.""[A flat lever battery] just wouldn't happen on these guys' bikes," Whittington adds. "I mean, I worked for a Conti team last year, and even with us, we would be changing those batteries for a stage race. So for every stage race, they'd get a new set of coin batteries in there just to rule that out, basically."As to whether you should be concerned about it happening to you especially if you're running Apex or Rival, which don't feature bonus buttons it feels very unlikely. "I wouldn't say it's a design flaw as such because it's obviously such a freak thing," said Whittington. It had never happened to any of his customers, he said, nor any of us at Cycling Weekly for that matter.So, keep those shifter batteries fresh and feel free to ride easy.Cycling Weekly has contacted SRAM for comment.