NAHBS – Crumpton’s New Full Custom, All-Carbon Corsa M Road Bike
NAHBS 2010 – Crumpton introduced his all new Corsa M full carbon road bike.Ã‚Â The only metal on the frame are the cable guides and the cage bolts, everything else is fiber and fully customized to the end user.Ã‚Â To illustrate the differences in frame building for a lightweight racer versus a beefy all around rider, the white Corsa M pictured above weighed about 1,200g (61cm) for the frame.Ã‚Â By contrast, he had an 826g flyweight (55cm) in nude carbon (shown after the break), too.Ã‚Â Same frame, just different tubesets and build characteristics.
On to the photos and details…
This is the lighter weight version…looks the same, only unpainted, so it gives us a better notion of the full carbon build.
Technically, the derailleur hangar is metal, too, if you consider that part of the frame. Click on any image to enlarge it.
Edge Composites was a popular brand with a lot of builders, which makes it surprising that they didn’t exhibit.Ã‚Â A lot of builders tried to use U.S. made parts where they could, and Edge makes it easy (albeit expensive) to source a lot of bits.
The Crumpton Corsa M uses PressFit 30 bearings, and Nick Crumpton was big on claiming the benefits of the pressed in system over BB30 systems, claiming lighter weight and greater simplicity.Ã‚Â Essentially, in a pressed-in system, the bearings are “pre-installed” into the frame, leaving nothing for the consumer to do other than clean the crank spindle/axle occasionally.Ã‚Â There’s no greasing, cleaning or lubing.Ã‚Â When they need to be serviced, they’re replaced.Ã‚Â Easy peezy.
Check out the tall, curved chainstays.Ã‚Â They add stiffness, but they’re the same carbon chainstays you’re going to find on other frames, too.Ã‚Â Few manufacturers make their own stays or dropouts, and Crumpton sources his from Dedaccai.Ã‚Â Of course, he positions and sizes them to suit the rider, and each stay (seat- and chain-) are attached to the dropouts at angles and positions determined by the builder…it’s not a pre-fab rear triangle.
Above and below, the Corsa M uses (and includes) a Chris King Inset Headset.
The rear end gets a bit of flair with a twin upper seat stay.
The Crumpton Corsa M is built to order based on your needs and fit for $4,800 and includes frame, fork, headset and PressFit 30 bearings.Ã‚Â There’s about a 7-month lead time.
Crumpton’s primary road bike design showed off a little creativity with the carbon wrap. The external cosmetic layer (most builders, even the big manufacturers, include a cosmetic outer layer) uses carbon fiber sheet scraps for a patchwork look that catches light well and adds a lot of visual interest.