For me the holy grail of bicycling and scootering has been non-pneumatic tires – that won’t go flat. I currently have urethane inserts in the rear tires of my Kickbike® and AW Footbike, as recounted in posts here and here. Unfortunately pneumatic tires are so good at storing and releasing energy that “airless” bike tires, sought for over a century, are deeply unsatisfying at least, and the market is microscopic.
On the other hand, auto manufacturers and customers, not the least of which is the military, know that the promise of airfree tires are worth almost any amount of research, and the Britek Tire and Rubber company has come up with what looks to be a brilliant plan. Most airfrees don’t spread road forces over the entire wheel nor do they release the energy that they soak up in contact with the road as pneumatics do; Britek’s Energy Return Wheel does:
Through the use of adjustable rods, the rubber is stretched which stores elastic potential energy in the wheel, turning the ERW into a 360-degree slingshot that retains energy (hence the term “Energy Return Wheel”). When the ERW is attached to an object, that object becomes sprung. Just like a garage door that is sprung, the attached object becomes de-weighted and requires dramatically less energy to move than an unsprung object.
Britek’s website doesn’t enlarge on their bicycle tires, but their YouTube channel has quite a few videos featuring bikes.