FATMAP difficulty grade
From Canazei, take the lifts to Col dei Rossi and from there the hiking path to Passo Pordoi: this trail is a hiking trail, hence dismount the bike if there are hikers (not advisable to ride this trail on summer weekends).
From the Pordoi Pass, pedal then hike the bike up to the Forcella Pordoi - it's a 800hm steep climb, only do it if you're in shape and can handle high alpine terrain well (good shoes required). From the Forcella take the coasting trail to Rifugio Boè: it's partly rideable, partly not. From the Rifugio climb up to the Antersass, from here the descent starts: it's a narrow exposed trail going down the Val Lasties.
Some sections might not be rideable, but it is for a good part (for experienced riders).
Once you reach the flat bit in Val Lasties, a faster, still technical trail goes down to the Monti Pallidi Refuge: from here you can take a fun trail that heads down to the lift that will link you back to the bikepark, where you can conclude this hard day with a final park run.