Who was asking about shaft drives?

[Fat Rat]

Can’t see it lasting even if it was brought to market
One thing that struck me straight away was the side loading that rear cassette is going to have especially on the larger rings the curved drive wheels and curved cassette is naturally going to force apart underload as there’s going to be flex on that rear cassette no matter what .

 

[oyster]

Could see market for it in professional road racing.

For ebikes better of using higher loss shaft drive systems from motorbikes. With ebikes , especially commuters low maintenance and reliability is far more important than efficiency.

Quite possibly you are right. However, increased efficiency helps enhance range. Also, didn't they claim a significant weight saving as well?

 

[Fat Rat]

modern implementation of a 120 year old idea.
Still brilliant though.

The old one is far superior we’re still using pinion drives today with high success

 

[oyster]

I'd be a bit concerned about its ability to cope with rain and mud, as it is.

Whilst I still know nothing, I have now read this:

FURTHER DEVELOPMENT
options for Driven can include, a double row ball bearings (further increasing the efficiency levels), a more optimised, possibly asymmetrical tooth design, material testing (advanced lighter and durable materials for the rear cog and front ring). The patent includes the possibility for a powermeter inclusion inside the shaft and a compact shroud can encapsulate the entire drivetrain to protect from mud, rain, and contamination

https://www.ceramicspeed.com/media/2979/driven_brochure.pdf

 

[Planemo]

Quite possibly you are right. However, increased efficiency helps enhance range. Also, didn't they claim a significant weight saving as well?

I am not convinced that directing torque through 90 degrees (twice) is any more efficient than a well maintained roller chain. And it is unlikely to be lighter when you factor in the additional weight (strengthening) needed to deal with sideways thrust loads. You only have to look into why all road sports and race motorcycles still use chains and sprockets. Avoiding side loads is also why straight cut gears instead of helical are used in race cars. Whoever designed this bicycle system may have solved/minimised the above issues but I remain sceptical.

 

[Woosh]

I can see it could prove rather fragile.
.

that's how they sell you tougher replacement discs.

There are plenty of lightweight sub 100g cassettes that work well.