We LOVE gravity bikes and to see such a massive long standing company such as Tange back the sport blows our minds. The Tange tubing company is working with a number of partners to release a propriety frame: the Yasujiro Speedbike. French enduro racer, rally driver and French Moto champion Serge Nuques pilots the Speed Bike at 130km/h down the side of an alp (be sure to check the video below).
Links:
http://www.asphaltgravity.com
http://www.cycleexif.com/yasujiro-gravity-bike