Valtontey from Aymavilles

It is well worth the 3km detour if you are climbing up to Lillaz. A beautiful panoramic view of the Gran Paradiso massif. Strange asphalt, in the middle it's all new asphalt and gravel corners, but very cycleable. Not a lot of traffic.

Val di Cogne, one of the side valleys of the wide Aosta Valley with 3 possible cycling endpoints at the end, climbed September 2023.
Long climb starts in Aymavilles with the steepest section at the beginning of the valley. Through several hairpin turns, you immediately climb steeply (5km - avg.7 ％) out of the town followed by slightly winding climbing through the forest lined by rock massifs. A short downhill through a gorge to cross the river followed by a second short portion of climbing (8％). Afterwards, the valley opens up again and you cycle on wide road slightly uphill with slight curves and a dozen tunnels and galleries along the river to the namesake of the valley : Cogne.
If you choose Valnontey as your end, after turning right in the tourist centre (rue Grand Paradis), it is another 3 km of climbing on fairly straight road along the gurgling mountain river where you effectively cycle into the Parco Nazionale Gran Paradisio.
End point is touristy and summer busy base for mountain hikers,hence car parks and catering facilities.
However, it is the fantastic views of the snow-capped +3000m peaks that ran with all my attention.

Practical : Busy summer/tourist traffic up to Cogne.
Flashing red lights as a cyclist in the tunnels never hurts!
Beginning of the climb can also be reached from Aosta city via the less busy Regional road SR20
which starts thv Pont Suaz on the south side of the river.

Busy but beautiful side valley climb with end point in the National Park.

Busy climb depending on the season, to be avoided on summer weekends. Without any particular difficulty, worthwhile for the panorama.