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Comment by AstralStorm | Hacker News Reader

As far as I'm aware chain was introduced to allow for light weight while keeping vibration resistance.

Can't this pulley system be trimmed down even further to one bar transmission?

Based on my experience with motorcycles, chains are better than shafts for transmitting torque. Shafts tend to twist over their length in high torque settings, whereas chains just "pull" with minimal stretching.

Specific to this product, how the hell would you keep the 20-30 "gear" bearings on the shaft clean and operating smoothly in anything but lab conditions?

I have concerns about the longevity of those itty bitty ceramic bearings in real world conditions where you're hitting bumps and cracks in the road while under load from pedaling.

Also, literally every part of that page screams "expensive AF" including the part where they don't talk about the price.

You can seal the bearings, but that cuts efficiency. That's not the only problem, though. The interface between the bearing and the bearing sprocket will make it rather unusable in very dirty conditions.

Their setup seems like an answer to a question no one was asking.

The gains you could get from improving drivetrain efficiency are very marginal. Everyone else is working on improving aerodynamics. That's the actual limiting factor in cycling, and it always has been.

I was looking at them and scratching my head too.

I hope these images are just for show, and that the real product will use shielded bearings or else they are going to get crunchy and destroyed fast.

I couldn’t find it on the mobile version of the site but a video of the pinion based drivetrain showed up somewhere else the other day, I think the post is likely in reference to that chain-less system

Shaft drive bicycles had their heyday in the 19th century when chains were unreliable.

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