CeramicSpeed’s Driven Concept Might Become the Most Efficient Bicycle Drivetrain
As mentioned (and slightly buried) by the article, the really fascinating part is that we already have consumer bicycle gears that deliver 97% efficiency: a Dura Ace groupset is expensive compared to the stuff you'll get at Wall-Mart, but they're sold at pretty much every cycling store. I wouldn't be surprised if the Ultegra and 105 (Shimano's next two groupsets by price) were nearly as efficient as well.
2% is nothing to sniff at in cycling (people pay thousands of dollars for that kind of advantage), but there are other factors as well: resistance to stress (sprints), ease of maintenance and service, and weight all factor into the utter dominance of the current groupset design. It'll be interesting to see if CeramicSpeed can advance their design on those fronts.
I use a single speed bike at the moment. Not because I hate gears but because I’ve never had a geared bike that didn’t constantly click on the outside gears. It drove me crazy trying to tune them perfectly and never succeeding. Forget increased efficiency. If a new design emerges that accommodates gears and is simple to tune properly, then sign me up. No idea if the design being discussed could offer this.
If this drivetrain achieves its claims I will be very impressed. Shaft drive designs have been around for as long as chain drives; and they have never been as efficient. So mush is lost in the torsion of the shaft. A 2% increase in efficiency is an absolutely massive gain. The cycling industry is littered with flashy looking innovations that don't live up to the hype. The basic design of a diamond frame and chain drive has not been improved upon for over 100 years.
But every now and then there are innovations that acually take hold. For example, the slant parallelogram derailleur, hydraulic disk brakes, suspension (for mountain bikes), and recently narrow-wide front chain rings. We shall see how well this drivetrain goes.
Check these out: https://pinion.eu/en a german startup which created a gearbox for bikes which works like the one in a car. Early Investment came from an engineer at Porsche.
Disclaimer: not affiliated
Very nice concept, I really like the fact that the casette is gone because it occupies a lot of space leading to substantial weakening of the rear wheel (the width of the hub where the spokes attach is a very larger factor in rear wheel strength).
That gear does look like something that would do well in a meatgrinder, and given the fall-out over just having disc brakes on racing bikes I don't think that would pass inspection for road bike racing.
10 points for out of the box thinking though, a cardan driven racing bike is very clever.
Yeah, that's going to skip under load and won't stay aligned.
Might be usable as an electric assist drivetrain and it was sealed up.
This is cool and really fascinating, technically, but ultimately a solution to a question nobody asked and I don't see many benefits outside of a claimed efficiency benefit while there are quite a bit of drawbacks. Also I'm failing to see how this is different from shaft driven bikes [0] we already have had for 'some time' now
The system would have to be pretty intelligent to know how fast the system is moving. It’d have to be pretty smart to know how fast it’s moving, which tooth track to select to make the shift happen. Would you have to back off to shift under high load?
This reminds me of some newer automatic transmissions that use dog clutches, like a manual one, relying on sensors and electronics to do the synchronisation --- there is a very noticeable (and unpleasant) jerk in the shifts, since it has to match the speeds precisely, and automatically reduces throttle to do so.
Of course, with a human providing the power directly, that's not really possible. I suppose you could add a "shift light", but IMHO that's just overcomplicating things...
Other options include CVT which offer continuous non-integer gear ratio steps, but a lower efficiency of about 79%.
They mention something about an electronically assisted shifter. Doesn't that defeat the whole point of a (non electric) bicycle?
My grandfather told me about a bicycle he designed that uses a CVT. Curious if that’s a better direction for the future of bicycles.
Unproven, can't yet change gears, based on an old design used over 100 years ago that was given up on.
> A stock Dura Ace drivetrain returned about 97-percent efficiency.
Does anybody know the numbers of efficiency in fixie and single speed bicycles? I reckon they should be better given the absence of a derailler? I tried to search for it, but couldn't find numbers.
I don't think the big cog will be stiff enough to not bend under the pressure.
"while the 13-speed rear cog looks like the unholy union of a compact disc and the Sarlacc pit from Return of the Jedi"
After looking at the thing, it is a remarkably apt analogy, too. I wonder how long it takes to machine.
Does anyone know if this would this be UCI legal?
Would this design not be... less of a chipper shredder if they switched the cylinders and the teeth?