the Ibis Tranny is a strong and lightweight monocoque carbon fiber hardtail. And a lightweight, laterally stiff, vertically compliant one at that. The Tranny goes far beyond being just a hardtail, as a result of some unique features. Several of the features came out of the removable, adjustable-length, chainstay. This means you can transform it from a single speed to a geared bike to a travel bike in a matter of minutes.