This is about bicycle wheels in particular but in general it could apply to any pneumatic-tyred vehicle, including motor cars and bikes. The issues are similar, but magnified when you look at a light-weight, essentially very simple design like a traditional triangular-framed "push-bike" design.
Punctures are a pain and put a lot of potential riders off, understandably. Whilst you can get good at it, and fix flats quickly, it's not a skill that you
really want to get a lot of practice at, either.
Now you can fill your tyres (or tires) and tubes with
self-sealing goop, and run
tubeless, too. It works, up to a point. But it's
not 100% reliable and it takes another skillset again to get accustomed to. But yes, it's a lot better if you can justify the expense.
But for most of us, punctures remain a "thing". And yet there
have been many proposals to remove the whole air-under-pressure part of the design, too. Like this recent one from Bridgestone:
(Via NewAtlas. You can read more about that
here.)
And there are other ideas, some already in production. In essence the compressed air is replaced with something else, like plastic or solid rubber, or the tyre itself is toughened to resist penetration. It works, but not well enough to satisfy most people.
The main problem here is reduced levels of
deformation, although the additional
weight can also add up. A traditional air-filled tyre will deform over small obstacles, maintaining contact and thus feel and grip. A solid or stiffened tyre is more likely to bounce, losing contact with the road surface. This is bad for grip, traction and comfort, and in a corner such rigidity could be disastrous.
Now you can add some
compliance to the bicycle frame itself - it's called
suspension, in effect - but the amount or degree of frame compliance needed becomes either uncomfortably wobbly and weird, or you lose too much forward motion through
energy dissipation. Again, you are adding weight as well as
complexity.
Which is to say, it's not easy to replace the air-filled tyre, as it works really well for our purposes. It's simple and cheap, too.
So how about the
Bridgestone design, pictured above? Well it holds promise, but it needs to demonstrate comfort and control as well as reasonable cost and weight. As I alluded to in the title, it needs to be deformable and track the road surface, maintaining contact, yet stiff enough to be
efficient. It looks like that is "designed-in" to the curving blades, so hopefully that's sorted.
But it also has to maintain lateral
stiffness under load. A bit of sideways give is OK but a
lot will waste energy and feel weird, like a "soft" wheel with too-few or under-tensioned spokes. If you have ever tried cornering (or even accelerating) on an under-tensioned wheel, you'll know just how spooky and off-putting that can be.
It also has to be narrow enough to not cause excessive
aerodynamic losses, although that's more of a concern above about 25km/hr. If you ride more slowly it'll be OK. It also has to simply fit into current bike frames.
And if you go off-road at all, or just ride through
mud, you'll want to
shed that mud, not collect it.
If any design meets these criteria and passes other tests, such as for safety and compatibility with existing components, then it may well catch on.
Otherwise we'll just have to keep searching and hoping for a solution.
