Nick Crumpton is always good for something super lightweight. In years past, his show bicycles have been built up by Fair Wheel Bikes (here and here) to weigh in at some pretty feathery numbers. This one takes the cake.
When we talked to Nick a while back about his Corsa M stock road bike offering, he hinted at using a new US-made carbon fiber tube set. Called Isogrid, it’s allowed him to create this 666g frame (55) that’s still as structurally and torsionally as stiff. It’s a carbon cord wrapped in Kevlar with super thin wall tubes. This bike is one of one. There are plans to make it available to customers, but Crumpton says he is still investigating the material. He says this bike’s tubes wall thickness comes in at 17/1000″ and they could get it down to 12/1000″ with better molds. Normally, his carbon tubes range from 40/1000″ to 60/1000″.
The inside of an Isogrid carbon tube.
You can just barely see the grid pattern on the outside of the tube as long as the light’s hitting it the right way.
The bike, sans pedals, comes in at 9lbs 12oz. They said the customer sent in the full build kit along with different wheels that were even lighter, but they wouldn’t show it with them because they didn’t think they were safe. This frame is about a 55 size.
Crumpton had to design new molded cable guides with a larger footprint to give it a big enough surface area to safely bond to the tube. They tested it with smaller mounting areas and the tubes were flexing when they braked, so the larger footprint was necessary to maintain frame integrity and keep the guides from delaminating of the frame. Similar reinforcements happened at the bottle cage mounts
Seatstays are Crumpton’s design, made by ENVE with Dedacciai chainstays like on the Corsa.
No set plans to offer it as is, but it will come in some iteration mid year in limited quantities. It’ll likely be around $6,000 with an ENVE 1.0 fork.
“I want to do a really light frame that people won’t get hurt on,” Crumpton said. “This (experiment) is the path to that.”
Just for fun, a few of the parts sent in by the customer (yes, it’s a dentist) were worth sharing. Apparently, the glossy coating on SRAM Red levers weighs too much, so that was sanded off. A small grinder/drill was taken to the rear derailleur, then metal stop screws were replaced with plastic.
In more down to earth news, his bikes will now be available in a red or blue matte paint option for a slight upcharge. It’s shown here on the stock Corsa M frames.
With not-new SRAM Red group and ENVE cockpit, it comes in at 14lbs 6oz.