Be warned as there is usually traffic on the road. If using this road as a downhill, look out for cars!
Leaving the small alleys of the old town of Nago (elev. 200m) you'll be on an asphalt road in the vineyards. The name of this road is Via Monte Baldo. It is possible to start lakeside in Torbole, follow marked path #632 and to reach this road at the end of the vineyards. The asphalt ends at a parking lot (elev.1.550m).
There are many amazing views down to Lago di Garda. With this in mind, it isn't too hard to keep biking this endless uphill.
You can also go this way by car and shuttle your bike (if there's someone, who will drive your car down to Nago) or by a commercial bike-shuttle.