The national park north of Tapei is supposed to be good for mtbing there are a few websites with details. I used to live in central Taiwan at the foot of the mountain range with Taiwan’s highest resort, Alishan. I often went riding in the high mountains but there wasn’t much in the way of singletrack as most of the tracks had been made into narrow concrete roads often heading up near vertical slopes. One thing to bare in mind is the standard of driving there is pretty appalling as drivers seem to have no sense of personal safety. I would often be riding around a blind bend with a car heading straight at me while attempting an overtake. But the worst were concrete mixer trucks. The drivers I would describe as homicidal maniacs. Keep well clear of them as they stop for no one.
