The ascent via the west-facing slope is not as easy as it looks!
The Col du Ballon (929 m) on the edge of the Plateau d'Hauteville offers a 9 km climb from Tenay on the west-facing slope, with its steep, irregular sections.
The route begins on a narrow, straight road on the mountainside, with views over the valley as far as Culoz, and ends with a series of very dry hairpins, followed by a steep climb to the plateau. The central section is relatively steady, with small switchbacks. A pass not to be taken for granted!