the 2018 edition of eurobike has announced its winning entries, which includes a chainless bicycle. developed by CeramicSpeed and dubbed ‘driven’, the system is still a prototype and currently requires a special frame. this revolutionary drivetrain concept aims to set a new standard in efficiency by eliminating the need for derailleurs and chains, replacing them with a pinion-style driveshaft system.
the driven concept has been developed by CeramicSpeed in collaboration with the mechanical engineering department at the university of colorado. it intends to have less drag, less weight, and take up less space than conventional bicycles. it also creates 49% less friction by eliminating all eight points of sliding friction. to achieve this performance, ‘driven’ uses a total of 21 bearings that play a crucial role. thanks to extremely low rolling friction and longevity, the bearings transfer torque from the front ring through the drive shaft, then onto the 13-speed rear cog.
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Love the engineers response to an innovation: “It’ll never get off the ground, Orville.” As a physicist, I endorse the input by engineers. Every physicist should own three or four engineers. Every one of your arguments here are given in an adiabatic range. i.e. “several links in a chain” as opposed to “only two or three bearings in contact.” Additionally, the comments on materials breakdown is stated without knowing the materials. By eliminating sources of non-conserved energy (several links in a chain), you gain in potential and kinetic energy. This is a fundamentally sound design. And the drive-by-shaft IS an old design, but is far more efficient than chain or belt drive. The drawbacks in the past for shaft drives were cost and materials. This ain’t 1959, folks. The materials and the costs therein make this sustainable, now. Ignore the engineers behind the desks.
I Like it. No more Chain! I wonder how well it changes gear ratios….how much noise is it smooth…Maybe the rear hub gear needs to have some gear teeth that retract and allow a smooth shift. All it might take would be gear plate laying on top of the other gear plate….that retracts during shifting….just a thought..or something like that. One step at a time…Right. Hope to see your idea on the street soon in Texas.
AND Hopefully it will work on Mountain bikes…my mountain bike gets tons of Texas black gumbo mud on it.
Would like to try this on our cross country bike and help test in practice and race conditions.
Not bad. Looks a bit tricky for getting close ratio gearing. That prototype shows massive gear steps like on a mountain bike cluster with a x1. Also agree with RBuss (yes another engineer + cyclist here) – a chain contacts most of the rear sprocket teeth at once, while this only contacts 1 or 2 bearings at a time. That is an overload issue. Also – they do not mention which gear ratio the % efficiency is being tested. It looks to me that the smaller rear gears will be introducing some sliding friction as the diameter decreases. Still like to ride it though. I hope it works and becomes a product, but I am not holding my breath.
Super slick forward thinking! Way to keep pushing back all these haters and actually create something! While these commenters are sitting behind their screens telling everyone why things cant and shouldn’t be done, you’re out there making an impact and inspiring people, keep it up!
Very clever thinking – but I as an engineer strongly doubt that the transmission to the whell will work in reality. There’s definetely an axial force implied and this would push the silver gears away to the inside. This stuff is going to jump over teeth and will be destroyed soon because once bended the axial forces will rise. Too, the carbon tube will bend outwards and the gear shifting friction will rise enormously under load.
Additionally, not calculated but estimated, the small bearings will be overloaded soon because there’s always not more than three of them under load, if at all…mostly only one.
Sorry, looks nice, but I think it won’t work.
@Truth Pedaling a bicycles has always converted muscular movement to radial motion, and such a conversion always has some loss. I’m not sure how this reality impacts the proposed solution. They claim, that their solution improves efficiency over the standard chain solution, not that it has no inefficiencies.
looks beautiful and interesting, but I doubt the small contact surface will be able to transfer real (more than a few hundred watts) power without distorting the cogs or jump over them …….
Cars have been using this type of transmission ever since.
Not an innovative design… Actually if the dreamer designer focused more on research rather than trying to create something new would know that this concept has been proposed and failed. due to its inefficiency of converting muscular movement to radial motion.
Still, nice though.