Chainless Shaft Drive Bicycle Transmissions by Sussex
by Warren McLaren, Sydney on 12.15.06
Bike chains and their associated hassles keep many people from pedalling off on the world’s most efficient form of transport. We done what we can to highlight chain alternatives, such as drive belts, hydraulics, and one or two bikes using the intriguing shaft drives. Well, now we have happened upon the folk who seem to have the patent on these shaft drive transmissions. Sussex Enterprises, of Taiwan, reckon they’ve been making then for the past 15 years but it’s only since the advent of the Shimano Nexus 7 and 8 speed internal hubs that they have started to get some traction, so to speak. The aluminium casing hides 35° bevel gears that the pedals spin to rotate an aluminium shaft, which turn turns a gear at the other end connected the Nexus hub. No external crank, no chain, no derailleur, no grease and grunge. Dynamic, one of the distributors, have a wealth on info on how it all works and they figure the eight speed option is equal to 20 speeds from a standard geared bike, plus a constant 94% efficiency is claimed from a system that needs next to no maintenance.
One other advantage is that gears can be selected without the wheels turning, great for commuting and stop-starts at traffic lights. Alas, the system is said not to be suitable for retrofits, requiring a special frame with a wider and shorter bottom bracket shell and special dropouts. But there are plenty of models available, like mountain, road, BMX and the cruiser and folder shown here. (The D-Drive by Dekra is an alternative range of three speed bikes). ::Sussex Enterprises
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Not exactly original and there are nice looking cardan bikes at Stycle
Shaft drive bicycles have been around for a hundred years. The shaft has never replaced the chain because it is less efficient. If this new effort gets more people on bikes, more power to it. But don't look for the shaft to replace the chain anytime soon.
it's true that all the gears of an internal hub gear are useful, while there are many overlaps in the gears of multiple chainring bikes.
But hub gears have a lower efficiency. Combined with the shaft drive, the loss of efficiency should be quite noticeable.
But the two together do make a very clean concept.
Hello ,
my name is Adrian.
I'm an industrial design student on my graduation year.
My graduation project is a bycicle that uses a driveshat mechanism.
My qwestion is , where can I purchase such a driveshaft?
Regards ,
Adrian.
Adrian, trying contacting Sussex direct. They might be able to help. Click the link at end of the post for their contact details.
they won't answer... )-:
Try a company called powerway. They make what you're looking for. I contacted them for one of my designs about a year ago. In the end I decided to stick with chain drive.
http://www.power-way.com.tw/
Here's an idea for some of you engineers out there. A hydraulic drive unit. A small vain pump in the bottom bracket with variable volume. connected by a small tube to a small positive displcement hydraulic motor to drive the rear wheel. This would provide practically no efficiency loss, and an infinitely variable drive ratio.
Bob
I purchased a dynamic brand 7 speed model. It is very clean and trouble free. You can bury it in the sand, pull it out and ride it (perfect for the beach). But if you want performance you will quickly outgrow it and move on like i did to a 24 speed. I am keeping it though, if nothing else, it is a conversation piece.
want to get a shaft drive bike? check out ebay auction. they come up from time to time. about 300.