At least parts of Hardangervidda is a national park. In the national park cycling is prohibited except on a limited set of tracks.
url: lovdata.no/dokument/LF/forskrift/1981-04-10-4830
“c. Sykling utafor godkjende traktorsleper og Tinnhølvegen er forbode.”

One the map on page 104 and 105 you can find the tracks where cycling is allowed.
url: docplayer.me/2573553-Forvaltningsplan-forvaltningsplan-forvaltningsplan-hardangervidda-nasjonalpark-med-landskapsvernomrade.html

Note: I don’t know if this map is up to date. I just found it with some googling.