Ceramicspeed DrivEn drivetrain

[Grubscrew]

Notice that it actually has gear linkages, and that the drive shaft runs neatly inside the chainstay. Ceramicspeed have some serious catching up to do.

[intern]

There's often good reason why things are the way that they are, which those ancient implementations of the shaft drive appear to confirm...it's not like bike geartrain engineers have been asleep for 130 years, they're looking for any advantage all the time.

[Breezer]

I think lubrication would be a big problem. In cars all the gears are submerged in oil. This system will screem like a pig when it gets dry.

[kosmonooit]

Whilst that has certainly has garnered a lot of media attention, anyone who has any engineering suss will agree it fraught with issues - that flashy fancy CNC milled rear sprocket thingy will face a lot of lateral pressure and go south as the driver cog step up its game, it will inevitably will start flexing / slipping, there is no positive drive like a chain and sprocket, inefficient as it may be. Maybe making it with some serious lateral support structure might help, which will mean its going to be very heavy

[kosmonooit]

I think lubrication would be a big problem. In cars all the gears are submerged in oil. This system will screem like a pig when it gets dry.

 

They are using small sealed roller bearings which is interesting - as the bearings engage they would not turn on the surface, so the thinking might be lubrication is not needed. However what about road gunge getting in there? There's no place for it to go, that will effect the functioning of the mechanism

[Hackster]

Haven't seen anything this dumb since disc brakes on a road bike / 1x drivetrains / 12-speed / electronic shifters / 29er wheels / gravel bikes / you get the picture

[Grubscrew]

there is no positive drive like a chain and sprocket, inefficient as it may be.

 

Positive indeed, but a chain drive is actually extremely efficient too. Ceramicspeed themselves rate a stock Dura Ace drivetrain at 97% efficient, and 98% efficient when fitted with their pulley system and UFO chain. The big 49% friction saving they quote is based on the 3% friction of the stock Dura Ace system vs the claimed 1% friction of their DrivEn system. 49% sounds like a lot but it's 49% of very little.

 

"According to CeramicSpeed’s testing, that best-case chain and derailleur drivetrain is Shimano’s Dura Ace enhanced with CeramicSpeed’s Oversized Pulley Wheel System (OSPW), and the company’s UFO chain which returned about 98-percent efficiency (averaged across all gear combinations). A stock Dura Ace drivetrain returned about 97-percent efficiency.

According to the information provided by CeramicSpeed, this means that Driven has 32-percent less friction than the CeramicSpeed enhanced drivetrain, and 49-percent less friction than the stock Dura Ace drivetrain."