Engineer Sergii Gordieiev is known for his DIY and out-there science experiments which he posts on his YouTube channel ‘The Q’, and bikes appear to be a recurring theme including the CeramicSpeed-esque chainless bike and a drill-powered ice bike. His latest invention, however, perhaps takes the biscuit... and somewhat miraculously, the the half-wheeled bike actually works! Could we see the big bike brands take note?
Deploying “Bikematics”, Gordieiev reassures us that 0.5 + 0.5 =1 so of course, this will work. I must admit I wasn’t convinced, but the video not only shows a walkthrough of how you can build your own, but also the bike dropping off a few kerbs without destroying itself. We’re impressed!
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Firstly, fair play to anyone willing to deliberately destroy a rim while riding a bike, that takes some serious commitment even if it does appear that the rim was weakened beforehand. Secondly, a bit of consumer advice: if you break your front wheel, it’s probably not the best course of action to immediately cut your rear one in half…
Obviously cutting a wheel and tyre in half does raise a few issues... firstly, how do you retain any air? Well, Gordieiev decided he didn’t need air and instead attached the tyre with pipe and rivets. We can’t help but feel that it’s going to have a negative effect on ride comfort, but we also can’t think of a realistic alternative solution.
Having made his two half-wheels and making sure the rear one can be driven using a chainring mounted to the disc brake (also not recommended) Gordieiev sets about extending the frame. It’s here that we see that Gordieiev is not only extremely creative but also absolutely excellent at colour-matching paint.
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So with the bike built, would it actually work? Well 'yes' is the answer, better than any of us could have expected! It is clear from the video that the wheels have to start out of phase, but while riding in a straight line they stay at opposites as they’re the same diameter.
Now, we did note that in the video there was a distinct lack of cornering, and that’s probably because as you go round one the wheels will travel a different distance to each other. That would result in them ending either both at the top or both at the bottom. You won’t be going very far like that…
Is this the future? Well, no probably not: it’s heavier, more cumbersome, has airless tyres and likely handles like an absolute pig… however as a feat of engineering, Gordieiev we salute you. The world needs more innovative and unusual concepts just like this one.
Let us know what your cycling-related invention would be in the comments below...
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17 comments
Glad I never lent him my bike.
I always wondered if those magnesium wheels were any good. Seeing one explode against a kerb answers my question nicely.
Utterly pointless but brilliant at the same time - chapeau.
I do think it's great but... some people really have too much time on their hands!
Disc brakes though... not only half as lethal again but surely this is crying out for rim brakes with interrupter gear?
If the wheels are chained together with no differential gearing, then they can't change phase by a meaningful amount, unless the sprockets are different sizes.
This. As long as the chain is linked in a 1:1 ratio and the rear hub is fixed there's no mechanical way for the wheels to get out of sync.
except it really matters that it is exactly 1:1 which it won't be. for a host of reasons. Though it'll be in sync for long enough for the novelty to wear off, about the length of that video
Why would they not be 1:1 like a tandem's cranks? Is there a chance he's connected them with e.g. a 28 tooth sprocket driving a 28.04 tooth one? What does the fractional tooth look like?
Something like this?
I think the two wheels will stay in sync cos no fractional teeth. Would be amusing to see the two half-wheels assembled somewhat out of phase however... it would be a bumpy ride.
Not sure but this also clearly needs either non-circular gears or a harmonic drive for the full tech demonstration.
Wouldn't it be like the Huygens phenomenon of the syncing pendulums?
Um, what host of reasons?
I was thinking about tolerances of the sprockets, but I think the chain is the defining factor, and that forces the 1:1 ratio (aka wearing and equalising the sprockets tolerance discrepancies), so in summary, I'm talking out of my arse. Not an engineer
Yes - I think cornering on this would be weird but entirely possible, because only one rear wheel is in contact with the ground at any given time (apart from a fleeting 'handover').
That said, UCI rules will probably mean we won't see this in the pro peleton any time soon
I suspect the sudden change in wheelbase at the handover would make cornering interesting, but not impossible. Might limit speed and how sharply it can turn.