Can an app make you a better cyclist? Strava, a website and app, has brilliantly tapped the power of GPS and egos of (mostly) men such as me to change the way millions ride. There has been criticism, too, that it promotes reckless or even deadly riding, and turns a beautiful sport into a computer game. But its success is now so great a cheats' site has emerged called Digital EPO (it might appeal to Lance Armstrong, one of Strava's better-known users). Strava works by allowing cyclists to upload rides recorded via its smartphone app or any GPS bike computer. Routes, be they two-mile commutes or 100-mile sportives, are mapped alongside times and data such as power output. Members may follow each other and create "segments," turning stretches of road into virtual race tracks. If a route takes in a segment, Strava automatically ranks the rider's time. The cyclist with the best time wins King of the Mountain (KOM), a name taken from the Tour de France, where pros fight to be awarded the polka-dot jersey for best climber. I had resisted signing up to Strava. I've had a Garmin for years and enjoy timing, discovering and mapping rides, but I'm no racer, preferring to challenge only myself. But as Strava has grown along with hundreds of other GPS-based fitness apps, its membership multiplying 10 times last year, all my like-minded friends are now using it. So last month I signed up to find out why. As well as logging rides, the site allows users to explore areas in search of segments. I had centred on my home in south London and found dozens, including the climb up College Road into Fountain Drive, a mile-long slog up to Crystal Palace. I've ridden it for years en route to Sunday spins in Kent, but had never thought about racing up it. The man to beat is Derek, the fastest among the 2,075 people who have challenged the College Road Hill Climb. His KOM time: two minutes and 24 seconds over 1.3km (average speed: 33.2kmh, or 20.6mph). I start gently before speeding across an invisible start line. The following moments are a blur of gurning and grunting as I power up the winding asphalt. After the final ramp to the virtual finish, my heart screams and my burning thighs threaten to melt my shorts. But have I done enough? Back at home, I discover that Derek climbs like an Apollo rocket. My time: two minutes, 57 seconds (average speed: 17mph) a full 33 seconds off his KOM. But, scrolling down the leaderboard, I see that I am 24th out of 2,000, which suddenly seems decent. Curious about Derek, I google his full name - and feel better still. Derek Bouchard-Hall is 42 and also lives in south London. But he's from America, where, from 1992 to 2002, he was a pro road and track cyclist. In 2000, his USA pursuit team finished some way behind a British quartet that included a young Bradley Wiggins. I had unwittingly set out to beat a pro. The next morning, I track him down to Wiggle, the online sport retailer, where he is in charge of performance development (an MBA and consultancy career followed his retirement). Bouchard-Hall loves Strava and, like me, had set out two years ago to make his digital mark in Dulwich. He had heard about the site in its early days, when word spread in the hills around its California HQ. Strava was founded in San Francisco by Michael Horvath, a Harvard grad who missed the camaraderie of his university rowing team. "We imagined a 'virtual locker room' where we could share workouts among friends," he writes. Bouchard-Hall was sceptical at first. "A bunch of grown men trying to compare where they stand seemed like a silly thing to do," he says. But then you get into it and realise how much fun it is and what it adds to your riding. I use it to find key climbs if I go somewhere new. If my dad does a long ride back in Florida, I get an alert and can send him a note saying well done. Chris Pook is an amateur racer on the Shropshire-based Paramount Cycle Racing Team. His Strava exploits have appeared on my Facebook wall since we met on the road a few years ago. The 30-year-old says the site has transformed the Sunday club run: "People accelerate at certain points if they know a segment is coming up. It pushes us to train harder and climb faster as the collective pace goes up. Strava won't reveal member numbers or the proportion that is male (it has been put at 90 per cent. Just 165 women have ridden College Hill out of 2,000). The site appeals perfectly to the macho geek lurking under the skin of even the most mild-mannered riders, not least the middle-aged in Lycra known as "Mamils" now flocking to Britain's B-roads. It also succeeds as a social network; status updates come in the form of rides inviting "kudos" points rather than likes. But women can be competitive braggers, too. Dawn Sealey, 35, joined the site in April having been "too intimidated" to join her male-dominated local club in the Channel Islands. "It allows me to track my progress and see how I compare with others without having to go through the formal or scary racing process," she says. I definitely try to beat other cyclists and the first time I got QOM I pretty much danced around the house. She later emails having discovered her crown has been taken: "Doh! Better get my bike out. But Strava is not universally loved. Many riders believe it encourages risk-taking in the pursuit of virtual goals. D L Byron is the Seattle-based publisher of Bike Hugger, the bike culture blog and digital magazine. He says Strava strivers "want the same high a slot machine may give a gambler if they keep pushing that spin-the-wheels button." The difference, he adds, is that "you're doing it in traffic, on open roads, with no sanctioning body or legal responsibility to a community of cyclists." A Californian rider called Kim Flint was attempting to win back a downhill KOM in 2010 when he hit a car and later died. He had been riding over the speed limit but his family sued Strava for negligence. Last month, a judge ruled the site was not to blame. "Every cyclist is responsible for their own safety and the safety of those around them," Horvath says in an email. In 2011, David Millar, the British pro now riding in the Tour de France, smashed the KOM on a circuit of Richmond Park in south-west London, among the most Strava'd roads in Britain. Using the bike he'd ridden to victory in the time trial at the Tour of Italy earlier that year, he completed the 6.7-mile loop in 13 minutes and 35 seconds, an average speed of 30mph. When it was pointed out the speed limit in the park is 20mph, his record was removed, the BBC took down a video of the ride, and Millar apologised for his "naivety." But the current record involves an average speed of 28mph and is still on the site, begging to be beaten. Some riders are so desperate to bag KOMs, they are prepared not to dice with death, but to cheat. DigitalEPO.com promises to virtually "juice" your virtual ride. The man behind it won't answer questions but the site appears in fact to be a satirical subversion of what it calls "obnoxious street-racing websites." Strava, meanwhile, encourages users to report suspicious rides. I decide not to take the risk and, my Dulwich climb now logged, I fear I may be hooked. Perhaps at the end of the summer, after more training, I can do better on College Road. Just five seconds gained would earn me six places on the board. Twelve would get me into the top 10. "That's a great effort," Bouchard-Hall says of my attempt to get close to his KOM. He really shouldn't encourage me. Update: The man behind the app Scott Lathan, the man behind DigitalEPO.com, replied to my email after publication detailing his motives in answers to my questions. Our exchange follows: Where did the idea from the site come from? Some background - I'm a road cyclist who rides 4,000 miles/150,000 ft elevation a year, certainly fewer than many Strava users but I'm no slouch either. When I first heard about Strava I thought it was a joke: "Really? Unsupervised street racing organized by a for-profit website? I'm also a programmer, and recognized that these files can be easily edited. There are no special skills involved, and took it on as a challenge. How popular has it been? The site has been popular. I don't pay too much attention to metrics but I get a lot of hits. Emailed responses are polarized, but they're about evenly split - I've been called a hero, and sworn at in several languages. What do you think about the rise of Strava and its effect on cycling? While it may be a good training tool, I find the competitive element of Strava to be horribly irresponsible. People have died and been seriously injured, and I believe injuries caused by cyclists chasing KOMs have been widely underreported. I've seen riding companions get irrational trying to maintain times - cutting in and out of traffic, etc., putting themselves, their riding companions, and pedestrians in danger. On a less serious note, I see a sport I love - recreational cycling - being turned into a competition. And as it turns out, there are quite a few of us who don't ride to "get there first." Ultimately we're all responsible for our own actions, and those actions include goading people into unsupervised situations which put themselves and the public in danger. Those who claim most street KOMs aren't accomplished without breaking the law are either lying or deluding themselves. Possibly we'll have to see a Strava-like site for automotive street racing or motorcycle racing before someone has the sense to pull the plug on all of these endeavors. What do you say to critics who suggest you are encouraging cheating? Or is that the point? Anyone who competes in sanctioned races knows Strava times mean next to nothing for comparative purposes. They don't take into account wind, weather, traffic, or drafting, not to mention gaming them at websites like mine and any number of other ways. Personally I think Strava is cheating the cycling community and anyone who wants to take a stroll without getting run over. I admit that if there is a Robiin Hood-esque element to "cheating the cheaters," I find that somewhat appealing.