No, the tires are not actually solid, but close. Popularly called non-pneumatics, they are molded polyurethane tires riddled with tiny air bubbles, so they’re not much heavier than pneumatic tires – and they won’t go flat.
Ever since my earliest bicycling days, non-flat tires were my holy grail. In the ‘seventies I found a pair that were about 1/2″ high and so hard that you could hear your spokes loosening as you rode. When I got into bike racing I fell under the spell of the cult of the sewup and forgot about my quest (which would never help my racing anyway).
Years later, when the internet arose, I started finding non-pneumatics that approached the rideability of pneumatics and began using them for commuting and errands. The first I found were Greentyres; however, the U.S. supply of these English “tyres” was erratic, to be polite about it. The tires were pretty nice, though; when they came, they came in colors and even when worn down past the tread were still rideable.
My next (and current – on my be-cobwebbed bicycle) tires are from an American company, Nu-Teck (alas, out of business 31 Dec. 2011), and they are quite nice. The ride is only about as harsh as a 150-psi track tubular, but like all non-pneumatics, the rolling resistance is higher than a pneumatic.
Adopting them on a footbike (the point of this post) would mean evaluating how much more rolling resistance they had. To that end I took my footbikes to a local hill and switched the front wheel with that from my bicycle, to see how long they would coast from a standing start at the top of the hill.
The hill climbs about 10 feet in around 200 meters. First I rolled down it on my Kickbike City Cruiser; then with the Footbike Street Model, both times with regular pneumatic tires. In a testament to the Footbike’s excellent sealed hubs, even though the Kickbike was slightly heavier, the Footbike rolled about 12 feet farther.
Then I put the non-pneumatic front tire on the Footbike and rolled it down the hill. (I only had a 700C from the bicycle, of course.) The Footbike with an “airfree” front tire rolled twenty feet short of the Kickbike – game over. Neither Nu-Tecks nor Greentyres come in 18″ for the rear wheel, anyway; just 16″ or 20″.
So forget the non-pneumatics for the scooter (where low rolling resistance is especially important). Makes me wonder how the smaller scooters with solid tires do roll, like the Xootr. But if you have a bicycle that’s been relegated to second fiddle (like mine – I’ve put baskets on it for grocery shopping), either the Nu-Teck or Greentyre (if you can wrest a pair of the latter from the factory) are pretty carefree, leaving you with more time for the footbike.
More updates on non-pneumatics, and a viable footbike option, here.