Are you ready for another solution to a non-existent problem?

[rccardr]

There's no inherent reason a system like this can be made to work reliably, given the appropriate application of cubic dollars and engineering hours.

For one parallel, look at electric high performance racing radio controlled cars, with which I have more than a passing understanding. In that sport, efficiency is everything. 30 years ago, the most efficient (non direct connect) drivetrains were chain driven. 20 years ago, shaft driven cars were dominant. Then belt driven drivetrains became prevalent. Now, it's pretty much to toss up between shaft and belt, depending on the specific course. 30 years ago we all poo-pooed the idea of belts or shafts being at all competitive. Now they rule the roost and chains are...gone.

[Mark McM]

Originally Posted by rccardr

There's no inherent reason a system like this can be made to work reliably, given the appropriate application of cubic dollars and engineering hours.

I'm sure it can be made to work reliably. But will it work better than a derailleur system?

There have been many attempts to replace the chain drive system, but none yet have beaten it for efficiency and weight. When comparing bicycle drive systems to those used in other vehicles, it is frequently missed that the bicycle "motor" is very different from most other vehicle motors. Specifically, while the bicycle "motor" has a low power-to-weight ratio, it also has an extraordinarily high torque-to-weight ratio. A pair of riders on a tandem may have only the 1% of the power of the engine in a small automobile, but they can produce about the same torque as the automobile engine - the tandem pair just delivers that torque at about 1/100 of the RPM.

Because of the nature of the low-power-high-torque engine, the drivetrain needs to have a very high stiffness-to-weight ratio and strength-to-weight ratio. Chain drives meet these requirements. While chains are poor at high power and high speed operation, but they are very good at low speed and high torque operation.

Edit: Regarding the torque and gearing of bicycle compared to other vehicles: A 1:1 ratio (directly drive) on a bicycle is considered to be a very low gear ratio - most of the time we are using ratios of closer to 3:1. Nitro-methane fueled top fuel dragster can produce 11,000 hp, and have top speeds of over 300 mph. They use maximum gear ratios of 1:3.2 (or about 1/3 as high as the lowest gears on bikes). Bikes achieve their speed by high torque, not high RPM.

[Steve in SLO]

Cool engineering? Yes.
Do I see myself using it? Probably not.

[Polyglot]

I see this mainly aimed at E-bikes where a single gear is sufficient (look at Tesla and virtually all other EV's) and as correctly pointed out, in the remote control vehicle world, as well as other applications, friction is a huge element. When you look at this from a pedal bike perspective it might not be the wisest expenditure of R/D money but I can readily see a good ROI.

[saab2000]

Originally Posted by Tony T

What next, disk brakes?

No, bikes with batteries and motors.

[fa63]

Your understanding is correct. On Ceramic Speed's website, they say the system can currently handle 200-250 Watts, which is an amount of power that wouldn't generate any meaningful flex/lateral forces on the drivetrain. It will be interesting to see if they can build this to handle a 1500 W sprint.

Originally Posted by Mzilliox

how would this work? as soon as you add any torque to the frame, those tolerances are our of whack and the things is no longer in contact where it should be. theyd have to make the frame the stiffest riding thing in the world to offset torque that would render this non useable.

or do i not understand anything anymore?

[retrofit]

Anyone find a video of someone actually riding a bike with this drivetrain? I haven't found one yet.

[Blown Reek]

Originally Posted by yinzerniner

https://www.velonews.com/the-drivetrain-wars

Please be advised that the word "brifter" doesn't appear once in the article.

[weisan]

Clearly, someone was inspired by...

[unterhausen]

I knew I had seen this idea before, a company was making roller gears back in 1898 https://www.google.com/search?q=Lloy...uvJgmr0FlT-yM:

A quick google search reveals that roller gears are used in worm drives that need to be free of backlash.

[GonaSovereign]

People have been refining this concept (off and on...mostly off) since at least 1899.
https://www.coopertechnica.com/1899-...ve-Bicycle.php

[93KgBike]

Originally Posted by old_fat_and_slow

Ceramic Speed Driven direct-drive drivetrain which eliminates the chain. ...

Umm,... yer dang right I'm a retro-grouch!

retro-grouch card REVOKED

[old_fat_and_slow]

Originally Posted by 93KgBike

retro-grouch card REVOKED

[pbarry]

Call me sadist, but I really want to throw a handful of sand at the drivetrain.

[Mark McM]

Originally Posted by GonaSovereign

People have been refining this concept (off and on...mostly off) since at least 1899.
https://www.coopertechnica.com/1899-...ve-Bicycle.php

Coincidentally, I was at the New England Vintage Bike show in Framingham yesterday, where a 1902 model of this exact same bike won Best In Show. The winning bike was rideable, although the coaster brake was acting up.