[atourgates]

As odd at is - this[1] design has a couple elements that have been reproduced in the real world.

While the exact 2wd system shown in the rendering would have some real issues, 2wd mountain bike systems do exist. They can rely on impressively strange chain routing[2], a system of gears and internal shafts[3], or just an electric hub[4] (which is admittedly, not really the same thing).

As far as the one-sided frame goes, Canondale makes a one-sided fork called the Lefty[5], that's in mass production and reasonably popular. One-sided rear triangles only seem to exist on motorcycles, and there's an interesting discussion here[6] on why that's the case, with an example of a one-off "righty" bicycle.

[1] http://www.gianlucagimini.it/wp-content/uploads/2016/03/Gian...

[2] https://www.singletracks.com/blog/mtb-gear/all-wheel-drive-m...

[3] http://christinibicycles.com/

[4] https://newatlas.com/easy-motion-evo-awd-big-bud-ebike/54434...

[5] https://www.cannondale.com/en/International/Innovation/lefty...

[6] http://forums.mtbr.com/general-discussion/why-dont-we-have-l...

[lmm]

I have a Strida ( http://www.strida.com/ ) which is one-sided on each wheel. It rides just like a regular bike, and means you don't have to take the wheel off to change a tube.

[salty_biscuits]

2wd on a bicycle is just plain silly. Weight and friction are such huge disadvantages to overcome. Even on a mountain bike extra traction from the front seems like a very limited benefit. I think Yamaha and Ohlins made a hydraulic motorcycle 2wd prototype. There the loses and weight aren't such a big deal. My understanding was that the extra material you have to add to strengthen the suspension sort of negates any weight benefits for telescopic forks. On motorcycles a single sided swing arm has the same issues, but at least there is a practical benefit when you need to change a tyre quickly.

[atourgates]

I think you're right, though 2wd eBikes might be different.

Our local trail association currently uses a Rokon: https://www.rokon.com/ - for trail maintenance, and it's just about perfect for that application. I could imagine them replacing it with a 2WD eBike at some point.

[salty_biscuits]

It really depends on center of mass and friction coefficient. Most cycling situations are wheelie before wheel slip. Even on dirt and up a hill the rider can just shift their weight backwards to get traction. A powered bike is probably different, with lower center of mass.

[lmm]

> 2wd on a bicycle is just plain silly. Weight and friction are such huge disadvantages to overcome.

Chains are pretty efficient (otherwise we wouldn't use them in the first place) and the weight difference would be tiny for a normal-weight person. If you've ever skidded in rain or ice 2wd seems like it could make sense.

[salty_biscuits]

Did you skid from beastly leg power or from braking or cornering though...

[dirtyaura]

I didn’t know about 2WD bikes existed! I’d love to try out to experience how it feels to drive 2WD.

The Lefty design also looks very interesting, do you have practical experience with it?

What an amazing comment full of new eye-opening information for me, thanks

[atourgates]

I've ridden a lefty a couple times, and apart from the visuals, it didn't really feel unusual. I more or less didn't notice that I was on a lefty.

Here's an article that looks at it a bit more in depth: https://factoryjackson.com/2016/02/18/cannondale-lefty-the-s...

I haven't tried a 2WD, but everything I've read suggests that the added weight and friction delivers pretty limited utility, at least in non-electric versions.

[romwell]

I've rode a design similar to Lefty on the Mobike bike-sharing program in Germany (Dusseldorf, but they are around in many cities).

The difference wasn't really noticeable (bike-share bikes are already hefty enough that this is a minor difference).

[samstave]

I rode the lefty for years. Its a great bike. Though, you can actually feel the fact that its slightly less structurally sound than a traditional fork.

But I loved it.