London Mayor Boris Johnson, in Melbourne, Australia, for a book festival, has ridden on one of the city's share bikes, but without a helmet. In Australia, people are legally obliged to wear helmets when cycling. Australian versions of city bike share schemes have largely failed to take off because of this compulsion.
Johnson told reporters Melbourne's bike share scheme could be rescued if Australia ditched its helmet law for cyclists.
He warned that enforcing a head protection policy threatened to kill off the initiative.
"It's not how we would have done it," he said, reports the Herald Sun.
"Obviously, it's up to Melbourne to decide what they want to do, but we took a very clear decision that it would be counterproductive," said London's mayor.
"I wanted to put the village back into London and create an environment where people felt safe cycling and safe cycling in numbers."
He added: "More and more of us will be living in cities over the next 50 years. But people want cities that are clean, green and which have a village feel."