TNR part 1 (Komoot description)

The route out of Turin to get onto the original first climb, the Colle del Colombardo, is direct and fast to give us more time to take on the climb. With a little re-mapping you will find quieter cycle lane routes a little to the north of the river Stura di Lanzo.

The Colombardo climb has a reputation, though it’s arguably not as bad as they say. It’s the equivalent of those first few bars of a great metal track that grab you by the scruff of the neck and then that’s it, you’re head down and rocking all the way to the end. Real Rally riders tackle the Colombardo and drink a cold, well-earned beer afterwards while basking in the knowledge when on that day, they were heroes and heroines...

After the Colombardo it's onto the famed Colle del Finestre, a long but exceptionally picturesque climb that leads onto the Strada dell'Assietta. After descending from the Assietta there's a brief climb up to Montgenevre through a unique tunnel before arriving at Briancon's fortified old town. After a few km of climbing the early stages of the Izoard climb out of Briancon it's time to decide on which section to take next - the wild Col de Peas 'rough stuff' route or the classic Col d'Izoard?

Forcella Lavardet gravel

Forcella Lavardet is a high mountain pass at an elevation of 1.547m (5,075ft) above the sea level, located in the province of Belluno, in the Italian region of Veneto. The climb features 14 sharp hairpin turns that seem to lie on one another, gradually climbing up to the top of the pass. 

The road to the summit is mostly unpaved, with some paved sections at the northern part. It’s called Strada Provinciale 465 della Forcella Lavardet e di Valle San Canciano 465 (SP465) and runs north-south from Campolongo, a small village, towards the paved Strada Statale 465 Road. It’s an old military road.

The road is closed to vehicles after some streams and detachments (since October 1993), but it is passable by bike or walking. The flood of October 1993 made the road, which had already been in precarious conditions for some time, definitively impassable. It features some very narrow parts and scary wooden bridges. Some years ago, the road was impassable after heavy rains, but now there’s a new wooden bridge to cross the river Frison, a section which was impossible to cross during several months every year.

It was nicknamed ‘the most absurd state road in Italy’. Tucked away in the Seppada zone within the Carnic Alps, the road is famous because its group of 14 steep, picturesque and spectacular hairpin bends, between San Pietro and the peak. Remember the road features a high risk of landslides. The road is pretty steep, hitting a 13% of maximum gradient through some of the ramps. Starting at Campolongo, the ascent is 10.4km (6.46 miles) long. Over this distance, the elevation gain is 599 meters. The average gradient is 5.75%. The road is pretty narrow, so it is advice to drive slow in the bends, as you will not see oncoming traffic.

dangerousroads.org 

Muro di Sormano

With less than two kilometres in length, it has an average gradient of 17% but has sections in excess of 25%. When the climb featured in three editions of the Tour of Lombardy in the 1960s, many riders were famously forced to get off and walk.

dangerousroads.org

Alto de l’Angliru gravel loop

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.

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%.

gravel portions look ok on google satellite view

Dangerousroads.org

Strada Berbenno di Valtellina-Caldenno

Located in the Province of Sondrio in the Italian region Lombardy, the climb is just brutal. The maximum slope is 40%. It’s one of the hardest and most epic climbs you can ride on two wheels.

The road is one of the Toughest Bicycle Climbs in the World. It’s asphalted with some concrete parts near the end, so it should be climbed with a mountainbike. Open to traffic throughout the year, may be closed for short periods in winter when the weather is bad. Some parts are extremely narrow, even for an average car. Totally impassable for 2 cars at the same time.

The road runs south-north connecting the villages of Berbenno di Valtellina (at 389m above the sea level) and Caldenno, at 1.811m asl, via 40 hairpin turns. The ascent is 13.5 km long. Over this distance the elevation gain is 1.422 meters. The average gradient is 10.53%.

Dangerousroads.org