US Secretary of State John Kerry has a history with broken planes, but during Iran nuclear talks in Switzerland this week, even his bike needed fixing.

In what skeptics might call a metaphor for the talks in Lausanne, Kerry's orange racer on Monday couldn't get into gear properly, Lionel Schumann of Sam's Bike shop in the town of La Tour-le-Peilz said.

"The Swiss police came in and told me they needed an urgent repair on a gear-change mechanism," Schumann said on Wednesday.