The Pre-Alps by bike
Starting from Serres, follow the D27 north. The route passes through Sigottier and its cliffs, which are popular with rock climbers.
Just past La Piarre, the Col de Carabès takes you into the Drôme department. Stay on the D106, which passes through Valdrôme (a small mountain village and the southernmost family-friendly resort in the Drôme).
Head toward Rosans by crossing the Col de Pommerol (Col de la Fromgère). Now ride past the former priory of St-André-de-Rosans, through Montjay, then climb the Col de Serre Larobe leading up to L'Epine. Head east on the D 994. These are the final pedal strokes to reach Serres.

Pommerol pass
Pommerol pass is a crossing point between Les Hautes-Alpes and La Drôme, two French departments. Also named Col de la Fromagère, the pass is reachable from the tracks of Suquet and Raton’s ridges. The pass overlook the public forest of Eygues.