A South Korean company believes it has invented a tyre that might just change the world. Jonny Cooper test rides the Tannus Aither solid bike tyre to test their theory.
Bicycle tyres are strange things. You rely on them every day to get you to and from work, yet largely forget they exist until – bang – one punctures at 7.43am on the wettest morning in December when you’re halfway between home and office. Cue 20 miserable minutes in the lashing rain spent changing your inner tube and slashing your fingers to pieces in the process.
Nothing can deflate the mood quite like a puncture – which is why various inventors have sought to produce solid tyres since the air-filled (or pneumatic) inner tube trundled onto the scene back in the mid 19th Century. The problems they have encountered have been numerous (too heavy, too weak, too vulnerable to heat), but the main sticking point has always been shared: solid tyres just don’t … roll.
Until now. Tannus, a family-run South Korean company with a background in the shoe industry, believes it has invented a solid tyre that performs just as well as its pneumatic counterpart. Quietly, and with all the humility that befits a firm more accustomed to making shoe soles than bike tyres, Tannus think they might just have changed the world.
The basis to their claim is a new polymer called Aither. Named after the Greek deity who embodied the pure ‘upper air’ that gods were said to breathe, the material encases minuscule air bubbles (each is about 10 micrometers wide) in a robust mesh of protective walling.
How does that help? Think of the honeycomb in a beehive. You can take individual cells out of the hive to harvest honey, but it won’t prevent the bees from functioning as normal. Tannus tyres are the same. Stick a pin into them and a handful of bubbles get burst, but the damage doesn’t spread. Unlike a pneumatic tyre, where the air rushes to escape from all round the wheel with an audible ‘whoosh’, the rest of the Tannus tyre continues unaffected.
So this one polymer, which took ten years of development to come to fruition, offers an ingenious solution to a very fundamental problem. But one big question remains: Does it roll?
According to Tannus, the science says it does. In the testing lab, the same amount of effort has been shown to get a pneumatic tyre travelling at 30kph and a Tannus tyre at 29kph. That difference might make a pro think twice before racing with Tannus, but it should be small enough to attract the attention of any commuter who has ever had the misfortune of fixing a puncture.
On the bike, you quickly adapt to any shortfall in rolling resistance. I swapped the Continental Gator Hardshell tyres on my commuting bike for two, black Tannus tyres over a month ago. For the first ten minutes of my first ride, I fancied I could feel a change: my bike seemed a little sluggish when accelerating from a trot to a canter (or whatever the cycling equivalent is). But after those ten minutes, I forgot. The tyres are still on my bike today.
And, importantly, they won’t deflate. Unless you diligently pump up your inner tubes every week, the likelihood is that you are running your bicycle at less than maximum efficiency. With Tannus, the rolling resistance remains constant. Suddenly that 1kph shortfall seems to make very little difference at all.
In terms of the ride itself, Tannus’s tyre feels a little bumpier than a pneumatic tyre, which is because they contain less air to cushion blows from the road. However – and here’s the clincher – if someone didn’t tell you that you were effectively cycling on solid rubber, you probably wouldn’t guess. And as the tyres are just as light as a normal rubber tyre plus its inner tube, your bike feels no heavier with its new set of shoes.
How does it last over time? I’ve yet to notice any alteration in the tyres on my bike – but they’re still very new. Tannus say that the polymer itself is remarkably independent, so heat or rain won’t change its molecular make-up. Under lab conditions as part of a roadworthiness test in Japan, Tannus outperformed most regular tyres, only diminishing by 1mm after 5,000km of use. Privately, the company is confident it will last beyond 9,000km.
There are downsides. Getting the tyres onto my rims via their patented locking system took me a good hour and enough profanity to fill a cookie jar – but then, I don’t remember fixing a picture the first time being that fun either, and at least with the Tannus you only ever have to do it once. (The one shop in Britain that currently stocks the tyres offers free installation – you’d be foolish not to accept the offer.)
The tyres also have a tendency to flat spot during skids, which means they’re not yet suitable for fixed gear or mountain bikes. An improvement on the polymer – Aither 1.1 – is expected next year, although whether it addresses this black mark on its copy book remains to be seen.
For the average road bike commuter, however, the Tannus tyre really could bring to an end the hassle of punctured riding. It doesn’t quite reinvent the wheel, but it does give it a damn good resole.