There was a time when if you mentioned audax to your mates you’d get a mix of reactions.

You’d be suspected of having a fetish for flapjacks, of sleeping in bus shelters and you’d be expected to turn up on your grandad’s bike built from girders.

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Your local bike shop would tell you that you’d definitely need mudguards, and a pannier, and to forget you ever had friends who rode carbon.

But somehow, audax has escaped from its slightly musty-smelling corner in the back-est of cycling backwaters with the numbers of people riding the events rising.

Audax’s are pretty simple affairs with no memberships of any national body required to take part; you just find an event near you on the AudaxUK website, pay the minuscule entry fee and turn up.

And although audax comes with a rule book that would stall a Brexit negotiator, you don’t have to worry about having to be inducted into a secret society to get through one. All that is involved is cycling between set points collecting stamps or receipts to prove you’ve covered the distance within an maximum and an minimum time. Racing is discouraged; cake is mandatory.

That’s about all there is to it; good company, great routes and gel-free calories.

It’s a formula that seems to be finding a new following. In the last few years the number of people taking part has risen according to the governing body AudaxUK. The number of cyclists taking part in organised events are growing steadily and, as of June this year, 17,600 people had ridden one of its events – a 6.3 per cent climb on the same period in 2016.

There seem to be a number of different reasons why the increase is happening.

One might be that events are rebranding themselves in a deliberate attempt to attract a wider group of riders. This year, London-Wales-London was launched to replace a well established 400km event and numbers jumped.

“In 2016 we had about 45 riders but when we rebranded and re worked the marketing we sold out several months in advance” says one event organiser.

It might be that riders are looking for a more sociable experience, an experience that audax delivers. “The camaraderie en route is one factor” explains Londoner Olaf Storbeck.

“You get to know new people all the time, and after a few hours of riding and chatting, you feel like you’ve been known each other for years.”

Others are just looking for a different challenge in different places. Manchester-based Rapha Ambassador Grace Lambert-Smith talks about expanding her horizons “I wanted to ride to places I wouldn’t ordinarily go and through parts of the country I hadn’t yet explored. Audax is the best way to do it with like-minded people for very little expense.”

It’s a bug that’s hard to shake off. Kevin Merrison from Liverpool recalls his first audax: “a hilly 100km where there seemed to be a secret world of out of the way cafes, and silver dolphin stickers.

“I met others who had ridden astonishing distances and gradually worked my way up to the 600km ride, surprising myself each time I upped the distance.”

It’s a path that might seem familiar to Grace Lambert-Smith who will line up to ride the Transcontinental Race between Belgium and Greece on July 28.

In many ways she’s typical of the new breed of audaxers. Organisers are reporting seeing more women signing up and a greater proportion of younger people trying long distances as part of an overall more diverse community.

“This year we had more riders saying they were from Rapha CC than many of the more established clubs” he recalls, “and we had big turn outs from clubs like Audax Club Hackney who didn’t exist until very recently.”

Some of this new breed of audaxer, like London-Edinburgh-London (LEL) entrant Nicole Turr, are inspired to get involved by the likes of-Lambert Smith, Jasmijn Muller and Emily Chappell.

“I spent a week in Girona with Emily Chappell in January” says the Bedfordshire-based rider “and I was completely inspired by her, I came home inspired, she opened my eyes to a different way of riding my bike. LEL being this year but only every four years, it felt like it was the next step up so I jumped in”

LEL is the blue ribbon event for British audaxers and it attracts a field from around the world. Of the 1,500 entrants who will try to cover the 1400km (870 miles) in under 117 hours, fewer than half are from the UK.

With well organised control points staffed by volunteers along the route all riders have to worry about is themselves and it becomes clear that it’s the test of mental stamina that keeps the event growing. The internal mental battle rather than just the physical effort is what challenges the riders.

London-Edinburgh-London started in 1989 with just 26 finishers. The 2017 iteration will take place July 30 with 1,500 riders attempting to finish and with more people taking up audaxes that number could well rise.