The other day, I got a package in the mail from Dynamic Bicycles. Hmm…what is it?
The good folks at Dynamic offered their “Crosstown 7″ commuter bike to us for testing. In many respects, it is like so many other commuter-oriented bicycles on the market — aluminum frame, mounting points for fenders and rear rack, upright riding position. Where this bike differs, however, is how power gets from the pedals to the rear hub. This bike uses a very clever and deceptively simple shaft-drive. Yeah, that’s right — no greasy chain, no chainrings to chew up your pants. In fact, Dynamic takes things a step further by mounting the shaft-drive to a Shimano Nexus Inter-7 internal hub. So, no derailleurs either!
Here’s how the bike looks once removed from the packaging and assembled (a process that takes all of 10 minutes):
Here’s some of the specs, straight from the manufacturer’s website:
- 7005 Aluminum Frame, butted for light weight
Aluminum front fork
Alex DA-16 High Profile Alloy Rims (28-38C tires)
Kenda EuroTour Tires, 700x35C, 50-85psi
Dynamic Street Shaft Drive
Shimano Nexus Inter-7 Gearing, All-internal (17-gear range)
Shimano Nexus 7-speed Twist Grip Shift
Tektro Quartz alloy brakes; front disc brake optional
Tektro 2-finger Alloy brake levers
Base price: $679.00
Shaft-driven bicycles have been around for over 100 years, but most were plagued by problems with complexity and durability. Not so for this bike — Dynamic’s shaft-drive assembly, manufactured for them by Sussex, appears in every way to be rugged, well-sealed from the elements and elegantly simple, both inside and out. Here is a picture of the shaft-drive as mounted on the bicycle:
Over the next two or three weeks, I will be riding this bicycle exclusively both for my work commute and for my recreational rides. Stay tuned for a full-length review. In the meantime, check out Dynamic’s excellent “FAQ” page. Also, check out their supercool Java-based animation of the shaft drive assembly in action!