When are you going? We are staying in Pollenca for a couple of weeks at the end of Aug with my family, and I know my brother is planning on hiring a road bike for a few days' pottering around the area.
The road to Formentor is winding, steep and spectacular, with a nice beach at the end of it, if you fancy something scary. Driving along it gave me palpitations (I'm not good with steep drops...)
Does anyone know if helmets are compulsory in Spain?