Are Chainless Shaft Drive Bicycles a GENIUS or TERRIBLE Idea?

QUESTION: Do you think the Driven drivetrain will make the leap from cool concept to derailleur killer? 🤔🤔

At this point, I need tires that stay inflated before I can even begin to worry about the efficiency of my drive train.

when building solar race cars, our numbers were 93% for chain and 86% for shaft. that was 800 lbs at 1100 watts. which really adds up on a 300 mile race.

Shaft drive bicycles have found a bit of a niche in industrial environments (e.g. navigating around large manufacturing plants or oil refineries) where efficiency isn't a major concern and the reduced risk of falls from getting pant cuffs stuck in the gears is a decent selling point.

2:53 - in motorcycles, chain drives typically waste 1 to 3 percent of the input energy, where shaft drives typically waste 5 to 15 percent of the input power. Bicycle shaft drives should have similar efficiencies to this.

considering bicycle manufacturers couldn't manage to get the tolerances right on pressfit BBs, it's highly unlikely they will get them right for a shaft drive system

me, an intellectual: Why do chains when you can do GIANT GEARS

When I was about six years old, my father attended a trade show and was fascinated by a shaft-driven tricycle (I believe it was called a Gear-o-cycle.) He bought one for me. It was bigger and heavier than the typical kid’s tricycle but not as big as an adult tricycle. It had a differential at the rear, but the welds that attached that differential case to the rear frame kept breaking. Eventually we gave up on it, the company that made it went out of business, and no other company ever took up a similar design.

This problem reminds me of the bushcraft hatchet. Everyone is always trying to come up with a high-tech replacement to the traditional hatchet. The old fashioned design has its drawbacks, mainly that its quite heavy, but in all other regards it excels. It is cheap, incredibly robust, cheap and easy to repair, lasts almost indefinitely, and mother natures plain wooden handle is both durable and acts as a natural shock absorber, protecting the users wrist from fatigue. Over the years I have seen a myriad of alternative designs, all trying to make it lighter, foldable, multifunctional, or more compact. All these attempts end up causing massive negative effects, such as making it vastly weaker, causing terrible vibration in the handle, poor cutting, low durability, and almost ALL of these high tech solutions are more expensive.... and are worse. The OG wooden handled, steel head hatchet nailed the design over a millennia ago. It is just the best design hands down, and you can get a basic one from Amazon for fifteen bucks, sharpen it, put boiled linseed on the handle, and you are all set for three generations of wood cutting. Just like the traditional bicycle chain, sometimes the problem has already been solved, and attempts to improve on the solution are not worth the effort.

I like chain-driven systems, but for mountain biking, the derailleur is so vulnerable to impacts. I think there's room for improvement.

Nitpick about 5:52, the shaft needs low tolerances. High tolerance means it is more accepting of error, low tolerance means it needs to be more precise.

I use a shaft drive bike for my commuter, and I also have a road bike with a traditional Shimano rear derailleur. Here in the Netherlands, having a shaft drive for cycling in the rain is a massive benefit. I have done virtually no maintenance on the bike in almost 5 years and I think the loss of efficiency is negligible when commuting at less than 100 watts (compared to other commuter/hybrid bikes I’ve owned in the past). I’ve also lived in dry, hilly cities and in that case, I agree that the a traditional bike would be much better.

The city rental bikes in Antwerp, Belgium have this drivetrain. They don't feel as smooth to drive as chain-driven bikes, you really feel the cogs when pedaling. I don't expect the tolerances to be very tight on these bikes but the fact that everything is super stiff and the cogs are so close to your pedals may have something to do with it.

The shaft drive is like the rotary engine of the bicycle world

Some 15 years ago I went to a major bike show in the UK and was excited to ride and buy a shaft bike for leisure. When it came to my turn the bikes shaft gearbox had detached from the wheel because of loose fasteners and the show staff had not the ability to fix it.

Coolest new thing Ive seen for bikes is an oval crank gear that made it easier when you were at the angle of least power and was wider where your leg was able to impart the most torque on the crank.

Belt drives look nice, clean and efficient. I’d definitely like to try one. Shaft drives are not going to get over the hurdles. Chains are great!

I'm really glad cost and simplicity was included repeatedly in this analysis. It really annoys me when people miss the obvious and practical uses and not just pure opinion on design. I think shaft systems are cool but I'm happy with my chain. I've ridden city bikes with a shaft system and not felt at any disadvantage for that use.

As someone who has replaced driveshafts and chains on machines for a living, I'll take a chain over a shaft any day.

To me, if the victorian/edwardian engineers choose chain over shafts then there's something in that. In them days, reliability and ease of repair was a big factor