FATMAP difficulty grade
This is a great ride with varied but constantly impressive scenery, and a wonderful restaurant waiting for you at the far end.
If you're feeling really keen you can combine this ride with a hike (https://fatmap.com/routeid/2188799) or a mountain bike ride (https://fatmap.com/routeid/2196110) if you're willing to do the road section on a mountain bike. For most riders, this trip is enough in itself and it will certainly provide a good workout for all but the fittest of cyclists.
Head out of Mayrhofen, initially going towards Brandberg but then branching off and taking the lower road which leads to a series of tiny villages including Ritzlastl, Nöslrain and Häusling.
The road up to these villages is a toll road (costing €8) for drivers but cyclists go up for free, which feels satisfying! The climb is never particularly hard and the height gain comes gradually rather than in spurts.
Things steepen up a bit after you pass through the village of In der Au and then steepen again as you pass Bärenbad, the village at which cars have to stop.
The only traffic which will accompany you from here on is the bus which takes drivers from Bärenbad to the Speicher Zillergründ itself. Keep grinding up, passing through a series of tunnels, to reach the dam at the western end of the lake.
The utterly spectacular Einkehr zum Adlerblick restaurant is waiting for you at the dam, and you'll have earned a few calories after the tough climb up from Bärenbad.
Take a stroll across the dam to feel the wild ambience of the lake and then head back down to Mayrhofen for further calorie replenishment!