Alto de l’Angliru (also known as Gramonal) is one of the most famous mountains passes in the sport, and one of the most demanding: 12.2 kilometers at an incredible 10.2%, grading out at a maximum of 23.5% not far from the top. Located in in Asturias, near La Vega-Riosa, in northern Spain, this is a road that some professional cyclists have even refused to climb due to how rough it is.
Some professional bikers have refused to climb this road due its roughness. The top of the climb is 1.573m (5,161ft) above sea level. The height difference is 1.266 m (4,154 ft). The climb is 12.5 kilometres (7.8 mi) long, an average of 10.13%. It is near 24% at its steepest. The first 5 km (3.1 mi) are an average of 7.6%— stiff but not over-demanding for world-class cyclists. The sixth kilometre lessens to 2.1% and has a short descent. The last half of the climb is more severe. From six kilometres to the summit, it averages 13.1%. The steepest part, the Cueña les Cabres at 23.6%, is 3 km (1.9 mi) from the summit. There are two later ramps at 18% to 21% (sources vary).
The surface has good conditions and the traffic is really short. Only at weekends there’s some traffic. Weather conditions, like fog and rain, are really usual daily, even on summer. Apart from a tiny blip where the road dips slighly down for a hundred meters or so a few kilometers up (a section that is followed by a stretch at 21%), there is really no respite anywhere on this monster until you get to the top. The road is windy and narrow. It’s one of the hardest and most epic climbs you can ride on two wheels.
There are 2 possible routes to reach the summit. Starting at Santa Eulalia, the ascent is 17.7 km long. Over this distance, the elevation gain is 1.403 meters. The average percentage is 7.9 %. And starting at La Vega, the ascent is 12.55 km long. Over this distance, the elevation gain is 1.248 meters. The average percentage is 9.9 %. It is arguably one of the most demanding climbs in professional road bicycle racing, having been climbed the first time in the Vuelta in 1999. The last half of the climb, from the six-kilometre mark to the summit, the average gradient is 13.1%. The steepest part, which has a 23.6% slope, is known as Cueña les Cabres and is located about 3 kilometres from the summit. The climb is no easier from this point, as there are two later ramps at gradients of 18 to 21%. One of the most fearsome climbs in world cycling, comfortably rivalling the likes of l’Alpe d’Huez and the Zoncolan, the Angliru’s vital statistics do not do justice to its ferocious nature. The savage ascent does not tell half the story. With leg-screaming slopes upwards of 21 per cent, including the wall-like 23.5 per cent ramp just two kilometres from the summit, L’Angliru is a truly fearsome climb. Furthermore, its undulating nature means it is not just a steady increase, but instead delivers blow after blow, just as the riders cry out for respite. The climb has featured several times in the Vuelta de España since 1999. In search of climbs to rival the Alpe d’Huez and Mont Ventoux in the Tour de France and the Mortirolo Pass and Monte Zoncolan in the Giro d’Italia, the Spanish chose Los Largos de Covadonga to rival Alpe d’Huez and the Mortirolo Pass and L’Anliru to rival Ventoux and Mount Zoncolan. Originally it had been no more than an old cattle track and was not known as a cyclist route. Once tarmaced, is desired by some cyclists.
The surface of the road is paved, and chains or snow tyres can be required throughout the year. First introduced into the Vuelta a España in 1999, the organisers hoped it would rival the famous Tour de France climbs of Alpe d'Huez and Mount Ventoux. Bradley Wiggins, wearing the leaders jersey, struggled on the Angliru in the 2011 Vuelta as the road kicked up to a gradient of a little under 24% and was unable to respond to a strong attack by the Spanish rider Juan Jose Cobo, who went on to take the Vuelta title. This was an episode that illustrated that the Angliru, like all the iconic climbs, could impact on the GC classifications. Fellow British cyclist David Millar, riding the Angliru in atrociously wet conditions in 2002 and having already fallen from his bike three times, famously threw down his bike as he neared the finishing line and withdrew from the race in protest. Millar's actions prompted race director Enrique Franco to defend the inclusion of the climb: "The Vuelta without the Angliru is like a five-kilometre marathon or a 15-minute football match." Frequent rain and fog make for hazardous driving conditions.