I use Downtube 9FS daily, 70km back and forth (35km/ one way) daily to my office, In July & August, me and some of my friends (using a Dahon MUp8, Vitesse D6, Birdy, Dahon Rood7, Pacific Reach, Tikit Bike Friday, Dahon Speed P16) went to Bandung from Jakarta, it's about 140km. Some route is an extreme uphill, an the temperatures reach up to 41 degrees C at noon.