The single most important innovation of in the history of the bicycle is the one that someone or another has been trying to render obsolete from the day it was introduced.
I am talking about the pneumatic tire, created 133 years ago. Of all bicycle innovations, it's had, by far, the most influence beyond the world of cycling: Without it, motorized vehicles would be no faster, sturdier or more reslient than those powered by animals, and modern aircraft could not take off or land.
What makes pneumatic tires seemingly indespensible is also their flaw: They are elastic membranes filled with air. If that air is lost, whether through a puncture or leakage, your carbon fiber wheels ride as if they're cast in lead. Having to fix your flat can make you late for work, school or a date (yes, I've ridden to those!) or lose time in a race. And, fixing a tubular tire was probably the closest I've come to performing surgery--which is one reason I stopped riding tubulars a few years after my racing days ended.
So it seems that every few years, someone comes up with an "airless" tire. About four decades ago, I had the opportunity to try a pair of Zeus LCM rim coverings. Essentially, they were solid polyurethane donuts fitted to bicycle rims. I did a half-century and a weeks' worth of commutes on them and felt as if I'd spent a year on a "boneshaker." Since then, a few other tinkerers have tried their hands at making "flat-proof" tires. Most never go beyond the prototype stage; a few are released and meet the same reception I had for the Zeus rim coverings.
The problem is that when you get rid of air, you also sacrifice buoyancy and resilience--the very qualities that made pneumatic tires such an important innovation. I don't know whether this is an insurmountable problem, but there always seems to be someone with more technical expertise (or simply a different kind of imagination) than mine who believes it isn't.
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| Photo from SMART Tire Company |
One such person is Calvin Young, an engineer based in (where else?) Portland. As an intern at NASA's Glenn Research Center, he started to work on what would become the Martensite Elasticised Tubular Loading (METL) tire. It's essentially the tire that allowed the Perserverance Mars rover to traverse the Red Planet, adapted for bicycles.
The spacecraft tires were woven from Nitinol, an alloy of titanium and aluminum. This makes them strong yet elastic--and flat-proof. (I would imagne they're more resilient than the Zeus LCMs I rode.) But they don't make for very good grip on slippery surfaces. So, one of the ways Young adapted the tires for bicycle use was to add a layer of our friend polyurethane. As I understand, it can be re-applied, further adding to the tire's durability.
SMART (Shape Memory Alloy Radial Technology) Tire Company, for which Young now works, plans to make these tires available to consumers some time in 2022. I'd be interested in trying them. They didn't quote a price, but I imagine it's a good bit higher than what you paid for your Continentals or Michelins or Panaracers.
