The drive system of a bicycle is one of those timeless pieces of engineering. Though changes and evolutions occur, the basics stay pretty much the same. At the heart of it all there has always been a chain. Until now. A Hungarian design team has put together a new system for two-wheeled propulsion called the “Stringbike“.
The design uses steel cables and pulleys, along with a pair of kidney-shaped discs moving in opposition to deliver power to the rear wheel. The transmission raises and lowers the height of pulleys along swinging arms. This allows for very smooth shifting between gears and even the ability to set one leg to do more work than the other, if that’s needed due to an injury or training requirements. There are a number of other predicted advantages, including a longer service life for parts, no need for grease that can get on clothes, greater ease of disassembly of the bike, and potentially lower manufacturing costs.
Check out the video and let us know what you think. If you’re a serious cyclist is this a design you’d be interested in trying?
(via PopSci and Hungarian Ambiance)
I’d be very interested to try this. Looking through their site – http://www.stringbike.com/ – you can see some of the details about how the gear shifting works, sort of one notch per pedal stroke, which is probably better for your knees than the traditional chain. It does look like a lot of mechanics, many more things to get messed up in a crash.
Thanks for pointing out the missing link, Howard. Fixed!
It’s interesting and clever, but in all my years of involvement in cycling, I’ve never seen anyone buy a whole new bike just to keep some chain oil off their pants. A belt-driven bike accomplishes that with a tenth of the complexity, and those aren’t flying out of the stores last I checked.
There are some neat features; not having chainrings hanging off the bottom could give one several inches more clearance on a mountain bike. The ability to change effort and leverage for each leg has good potential for rehab devices or exercise bikes.
The speed of that rear wheel change will surely keep this out of competitions, though.
Wonder how you’d work in a suspension?
Andy or Dave, can a chain drive bike be converted to a belt drive system? “b”
That’s a lot of small, finely crafted parts for a bike. My question is, if you’re going to get rid of the circular-motion chain drive, why not get rid of the circular-motion pedals? Imagine if the pedals just went up and down — you wouldn’t need that complicated kidney-shaped piece holding the pulley.
“That’s a lot of small, finely crafted parts for a bike.”
Compared to the design of a rear derailer, that has to keep the chain tight, move up and down and side to side to accommodate the different sized gears?
I’ll take the pulley system any day.
“why not get rid of the circular-motion pedals?”
How would you get the pedals back to their starting position, and translate up/down motion to forward/backward motion, without adding comlexity into the design and manufacturing? And what would be the point?
Later, Seeker