Priority Cycles. Damon Madsens 13 Cm-travel Trailbike
Damon Madsen, a Twin Falls Idaho frame maker by night and a machine operator by day, is Damon Madsen. Priority Cycles, his start-up, has produced a few frames including 29ers and cyclocross, but Madsen’s heart beats for a long-travel bike that can pound over difficult terrain. Madsen, his wife Rebeca, and their son made the trek to MBA to attend a session about his latest creation, the aluminum-framed Portafortuna.
Damon Madsen, Priority Cycles Portafortuna RC photo
This bike has a Foes-like monoshock back triangle that drives a Fox Air damper at a low leverage ratio of 2:1. Madsen tried many suspension designs including Horst-type and dual-link linkages. He ultimately settled on a single-pivot swingarm that had a forward hinge position. Madsen discovered that the best pivot location to connect a swingarm was three inches above the bottom bracket.
Damon Madsen designed reinforced arches and an asymetrical swingarm to route bottom bracket’s rear triangle topivotahead. RC photo
The frame is made of various diameters 7005-alloy aluminium and includes provisional architecture. He doesn’t have a tube bender so the curves are routed with cut and welded doglegs. There are also some cutting edge construction techniques such as the hollow swingarm-pivot structure, which is made from mirror-image-machined halves that are then welded together.
The Portafortuna frame’s boxed, forward mounted swingarm pivot is visible below. RC photo
Many new bikes are available for me to ride. Most of them are sleek, shiny productions from well-funded corporate sources. They look great and most importantly, they ride just as well as their appearances. To prevent lateral flex, the swingarm drives the Fox shock through an aluminium scissor link. RC Photo
It turns out. It turns out that the Portafortuna has a great handling ability. Damon managed to squeeze enough weight out of his creation to make it less than 14 kg. This is a good average for an aluminum-chassis mountainbike.
The Portafortuna’s long seat and strong chainstays are supported by a robust through-axle, and beefy rear dropouts. RC photo
Damon will need to incorporate some construction features and smother lines into the Portafortuna if he wants it to be a success. But I think there are many people out there who can see the potential in the design and know how to build one. Priority Cycles is a company that I will be watching for innovative dual-suspension designs.
Contact Damon at www.prioritycycles.com-369-6396
The Portafortuna made it easy to climb. Madsen’s design echoes Brent Foes’ claim that forward swingarm pivots, low-leverage suspension rates and simple solutions are the best options for no-bob trailbikes. Damon Madsenphoto
Damon and Rebeca pose together with their Priority Cycles Portafortunas. RC photo
