Giro d'Italia: The Independent rides up the Stelvio Pass - cycling's killer climb

As the Giro tackles the brutal climb, Simon Usborne takes on the snow and switchbacks – and soon realises what the fuss is about

Simon Usborne takes on the snow, the endless hairpin bends of the Stelvio Pass and tries on the pink jersey of the Giro leader

Downpours, snowstorms, freezing fog and chest infections have already turned this year's Giro d'Italia into an epic tour of attrition, one of the toughest in the event's 104-year history. It proved too much for a sickly Sir Bradley Wiggins, our knight in shining Lycra, but - weather permitting - the greatest challenge will greet the survivors on the startline tomorrow. A mountainous stage 19 presents a course profile as jagged and hospitable as a shark's jaw. At its centre: one of the most fearsome, storied climbs in cycling.

The Stelvio Pass has elicited raptures from visitors as diverse as Charles Dickens and Jeremy Clarkson, who declared it the world's greatest road for driving. The pros who conquer it on two wheels, often deciding the fate of the Giro's maglia rosa, or pink jersey, ride into sporting legend. Those who flounder curse its every precipitous switchback and snowbound summit.

It was here, in 1953, when the Giro first climbed the Stelvio, that Fausto Coppi sealed his own legend by winning his fifth pink jersey. Coppi, whose stature is almost of Papal proportions in Italy, had trailed his Swiss rival, Hugo Koblet. But in a breathtaking display of might, the Italian attacked 11km from the summit of the Stelvio, breaking Koblet and riding on to victory. He said he felt as if he “was going to die” during the climb, now also named Cima Coppi in his honour.

The joy of road cycling is such that any rider can pedal in the tracks of heroes. Few lovers of ballet may perform a pirouette badly at Covent Garden, nor may a Liverpool fan slot one home at Anfield. But anyone with a bicycle can ride up the Stelvio Pass. How hard could it be?

Sunshine makes the ski resort of Bormio feel warmer than the thermometer's two degrees. With two pairs of booties over my cycling shoes and a bag of layers on my back for later, I set off alongside Daniele, manager of the bike-friendly Hotel Funivia and a veteran of more than 100 Stelvio climbs. “I have a good relation with pain,” he tells me, unnecessarily.

The Stelvio's stats are scary enough. The crazed road winds up via 35 of the tightest hairpins in a single, unrelenting climb of 14 miles. It gains more than a vertical mile as it rears above Bormio to 2,757 metres, the second-highest paved pass in the Alps. Viewed from below, the road resembles a giant strand of spaghetti dropped from the heavens.

As we rise, passing through dark, dank tunnels carved out of the rock, we hear only our breathing and the faint rumble of rubber on road. Not long after we duck a barrier that keeps out cars when conditions are bad (Stirling Moss came a cropper here in 1990, veering off the road during a vintage rally) our surroundings turn from green to white. A head-sized rock tumbles on to the road in front of me. I steer round it, also dodging lumps of ice and the snow encroaching on to the asphalt.

The Stelvio is the work of Carlo Donegani, an engineer tasked with linking Lombardia, then part of Austria, with the rest of the Austrian Empire. It took 2,500 men five years to build the road, which extends for another 15 miles on the northern, even more dizzying, side of the pass. When it opened in the 1820s, Donegani was revered across the Empire, becoming known as progettista dell'impossibile, the “designer of the impossible”.

His masterpiece became an Italian landmark, as the writer Daniel Friebe describes in his book: Mountain High. When the literary translator F A Malleson visited later that century, he speculated that Charles Dickens may have been referring to the road in this passage from David Copperfield: “I had found sublimity and wonder in the dread heights and precipices, in the roaring torrents, and the wastes of ice and snow.”

Later the stage for war, it has become most famous since Coppi's victory as a theatre of cycling battles, earning a place alongside climbs such as Ventoux, Alpe d'Huez and Galibier. In 1961, it was Charly “Angel of the Mountains” Gaul whose Stelvio heroics lit up the Giro. Later that decade, before Marco Pantani's time, came the era of two more greats: Felice Gimondi and, best of all, the Belgian Eddy Merckx.

The day before my ride I had lunch (pasta, naturally) with Pietro Santini, founder of Santini Maglificio Sportivo, the renowned cycle clothing company that makes the pink jersey of the Giro itself. Santini, 71, is a lifelong friend of Gimondi's and has climbed the Stelvio since Coppi's era. He also remembers driving up the road in his wife's new car about 15 years ago. When an avalanche threatened to sweep him off the road, he steered into the bank. He survived but the car was a write-off.

I ask the Santinis, who have run the company since 1965, to put me in touch with Gimondi, now 70. What are his memories of the Stelvio? “It is one of those climbs that scares you the most,” he says. “Even if you feel good, it's difficult to control. It's long and raises so high you must beware of the lack of oxygen at the top.” He remembers traipsing through snow during the 1965 Giro, only jumping back on his bike when the road reappeared.

Climbs such as the Stelvio and conditions like those that frequently dog the Giro help elevate it above the more famous Tour de France. It's why, perversely, Wiggins was so desperate to win a 2,000-mile race he told The Independent he “despises”. “The Giro is much more about the sport,” he said. “It's just craziness and there's a part of that the riders really like.”

Climbs and suffering add drama, romance and unpredictability to the race. Michael Barry is a Canadian cyclist who has raced in five Giros. He rode alongside Wiggins with Team Sky in 2010. “There are harder climbs but iconic roads like the Stelvio make the Giro special because they conjure images of past champions, and the history of the sport,” he says from Toronto.

They have also helped express and shape Italy's identity. Herbie Sykes, a British writer based in Turin and author of Maglia Rosa: Triumph and tragedy of the Giro d'Italia, calls the Stelvio one of the “great theatres” of the Giro. He adds: “There is a great tradition in Italy of literature and poetry around cycling... and a profound understanding of what cycling has meant to the country... its peaks, troughs and struggles.”

The final stretch towards Stelvio presents the biggest struggle. Having eased slightly, the road rears up again for the savage switchbacks leading agonisingly towards the summit. I can see it but, with just one and a half miles to go, snow carpets the road ahead. It's too dangerous to go on and so, after 90 minutes of climbing, I pause to catch my breath. Before I descend, a thrilling, chilling experience (imagine a wind tunnel in a walk-in freezer) I pull on Santini's maglia rosa, potentially disappointing the Giro gods who only award it to the greats. But it's my small way of honouring a captivating climb and those of all standards who have pedalled up it. Thawing over coffee back in Bormio, I vow to return in warmer weather.

Santini runs an annual organised ride that finishes at the summit of the Stelvio. Find out more at: santinisms.it