Here’s another excellent paved cycling climb with an extension that requires a mountain bike. The route includes four cols: (a little known Col de la Forclaz, Col de la Colombière, La Clef des Annes, and Col des Annes).
I started by climbing the paved classic north side of Col de la Colombière from Scionzier. See here for the much steeper alternate way up the north side via Col de Romme.
Note, when you look at the map, you’ll see that after ten kilometres, I made a brief detour. I basically followed a steep but good quality hiking trail for a couple of kilometres to reach yet another Col de la Forclaz (1320). I have a silly hobby of collecting Forclaz.
Common in the north French Alps, “Forclaz” means narrow gap. I think I have cycled 7 or 8 Col de la Forclaz.
This is a short, unedited video just to show the trail quality to La Forclaz (steeper than it looks).
Next, I rejoined the paved road. The last three kilometres to Col de la Colombière are always difficult, averaging 10%, with the final full kilometre averaging 11%. Here’s a drone view of the final kilometre:

I didn’t stay long at the col as it was fairly crowded. Lots of cars parked for the views, hiking, the restaurant, etc. I would descend the first 2+ kilometres of the south Le Grand-Bornand side.

Then, as shown on the map, I turned left off of the main road onto a local farm road that soon becomes gravel. It basically climbs through cow pastures and ski slopes.
It’s magnificent:

This eventually reaches the top of the ridge and another official col: La Clef des Annes (1747 metres). The view of the Aravis Alps are fantastic.
From here I could see Col des Annes slightly lower in the next valley. To reach it I would next traverse a good quality hiking trail:
There is also an excellent paved route to Col des Annes from Le Grand-Bornand. Very steep, but quiet, and beautiful. I rode it once during a warm December. Details here.
Anyway, at Col des Annes (1722m) there are a few farms, and a couple of restaurants. there were quite a few people again. For the col-hunters, it is possible to make a quick there-back to Col de Borneronde (1680m) but it’s too steep to go over the top. Here’s a very old post that shows the route.

Next was the crazy part of the ride. I would descend the back side of Col des Annes via a hiking trail. The route is through a back valley parallel with the Col de la Colombière route I had first climbed. It would rejoin that route at Reposoir.
WARNING: The first 2+ kilometres are very steep and rough. I hiked virtually all of it. Eventually, just above Sommier d’Aval I reached a farm road. It’s hyper steep, occasionally rough, but generally rideable after this. I have no photos of the hiking stretch, but below is a view of the farm road in both directions before it enters a forest.


Finally, I reached the very well preserved 12th century Chartreuse de Reposoir monastery. Put “Chartreuse” in the search box and you’ll find quite a few north French Alps rides past Chartreuse monasteries. In fact, many of my local home rides pass the less well preserved Chartreuse de Pomier, closer to Genève. The head monastery is in the Chartreuse Alps between Chambéry and Grenoble.
Here’s a photo of the monastery below in the distance taken earlier in the ride from the paved road leading to Colombière. Behind the monastery is the tight, steep valley that I descended.
Those familiar with Col de la Colombière will now notice that I could have returned to the start by first climbing to Romme and descending the steep alternate route mentioned earlier. It’s an excellent plan. But I was too tired/weak. I simply and descended down the main Colombière road back to the start.
A 3D video of the ride: