From the centre of the village of Fondo (by the town hall) an initially steep uphill road will take you from via San Martino, right by the church of the same name, out of town up to the Gampen Pass. After crossing the mountain pass you will soon reach the crystal clear waters of Lake Smeraldo. After just 200 m turn left along the green dirt track that the main road passes underneath. You are now on the route of the old mountain pass up towards the Gampen Pass. This dirt track is quite tough in places but the advantage is that there is no traffic. After about 1 km from the start you will cross the mountain pass again, after which the route continues on the west side of the main road mostly in complete isolation.
At km 5.0 you will reach the tranquil village of Tret, which can only be accessed by the steep Via Principale. At km 6.0 you will get to the mountain pass, just 200 m on the left-hand side towards the Gampen Pass. Now you can leave the main road again, heading right. The route to the Parkplatz (km 7.0) by the Scoiattolo Restaurant is unpaved, but you must focus on the next section which is a very steep dirt track leading to Felixer Weiher, at km 9.6. In between, you will ride through a wonderful stretch of larches, particularly impressive in the Autumn when they are ruby-red. To the left of the lake this scenic route takes you to the Waldruhe Guest House and to the Felixer Alm, as well as down to the shores of the crystal clear lake with its beautiful display of reeds. A break here is a definite must.
The relatively easy ascent through the forest is then followed by an exciting ride on the narrow trail back to Fondo. From the crossroads (km 10.9) where you came to the lake at the start, you will now turn eastwards and uphill. After an ascent of 900 metres and 40 metres further on you will come to another crossroads at Troisi (km 11.8). Here, you should make sure you don’t take the route on the right towards the Malga di Fondo (alternative route with no single track and with a section where you have to push your bike). Just before it, there is another access route, also on the right, leading to a dirt track through the woods, which takes you to the east side of the Dos de Solomp without going down (signposted as hiking track 517). Follow this route for about 400 m until you come to a fence. Immediately over the fence you will find a narrow trail on the very steep mountainside of the Solomp-Ridge. Here the path is heavily overgrown and goes further uphill, so that you will need to push your bike in places. Furthermore, the mountainside is very steep and steering to the left will prevent you from falling. Far below you can see the forest road that takes you down to the Malga di Fondo. You will reach a fresh water spring (Solomp Fountain, km 12.6), then passing through a fence again you will come to another dirt track. Follow this route heading south, but only for a few metres, before leaving it again when you reach, at km 13.4, the access to a stunning single track on the left. The track 517 later becomes Via delle Regole, which will lead you all the way to the mountain pass (km 18.4). From here you will follow the way back (or take the route at Lake Smeraldo which joins up with the Rio Sass Gorge - Tour 1411).
The track 517 has sections with different levels of difficulty up to a maximum of S1. At the Troisi crossroad, if you have opted for the alternative route along the Malga di Fondo, you will approach Lake Smeraldo and Fondo from the east.