Voiron sits where the Isère valley meets the foothills of the Chartreuse, a manufacturing town of twenty-two thousand people about twenty-five kilometres north-west of Grenoble, and it makes things that matter to riders and to anyone who likes a drink. The monks of the Grande Chartreuse monastery, hidden in the mountains above, have made their herbal liqueur since the eighteenth century, and the cellars where it is aged and bottled are in Voiron, said to be the longest liqueur cellar in the world. The town is also where the Rossignol ski company began in 1907, a reminder that these valleys feed the Alps with both hardware and thirst.
As a start and finish, Voiron is very useful. It has fuel stations on every approach, supermarkets, bakeries and a long main street with cafés, and the suburbs of Coublevie and Saint-Jean-de-Moirans run into it. Grenoble's traffic is close enough to cause delays on the roads at commuting time, so leave early or wait until after nine. From here the roads head toward the Vercors balcony roads and the Ardèche gorges, and the first hour is a gradual shift from industrial valley to mountain air.
To the east, the Chartreuse massif rises in vertical limestone cliffs, grey and cream, with forest on the shelves and meadows above. Its roads, which include famous passes like the Col de Porte and the Col du Cucheron, are among the best in the French Alps, but they lie behind the ridge, and on the way out from Voiron you only get the sense of their scale. To the north lies the Lac de Paladru, a glacial lake with clear water and a long public beach, which makes a good swim stop in summer.
Food in Voiron leans toward the Dauphiné and Savoie, with gratin dauphinois, walnut tarts and local cheeses such as Saint-Marcellin. A coffee on the main street before setting off is the right way to begin, and the same coffee in the evening is a fair reward for coming back. Winter mornings can be icy on the valley roads, so check the temperature before you leave.