He said Rhyne was letting the tire warm up and then it would inflate. Rhyne had to show him there was no valve stem and no air in the tire.
Up to that time, the two said they had to "beg, borrow and steal to get a mold." Rhyne said they then got some molds from France, and they refined that concept to the point where the two equipped a Corvette with Tweels and drove it successfully from South Carolina to California and back.
One key element was using the bead from the Pax run-flat tire that Michelin had unsuccessfully tried to perfect at that time. The bead from Pax worked well with the Tweel concept.
Sometime around 2000, after working under the radar for three years, Cron and Rhyne got the freedom and support to work on the project full time. Cron said from that point until about 2009, they worked of a wide variety of potential applications. From the Segway to IBOT wheel chairs, the Tweel was getting a lot of notice.
Rhyne said one hangup, however, was something referenced in the "Innovator's Dilemma," a book by Clayton Christensen. One aspect is that new technology really needs to start from the bottom and work its way up. "Of course what the company wants to do is start at the top because that's where the money is," Rhyne said.
But the unveilings in 2005 at the Detroit and Paris Auto Show were too early, according to Cron. "We could drive around in a car, but we were nowhere close to being ready to go to market with that," he said.
On the other hand, the Tweel was excelling in the mundane applications, such as lawn mowers, skid loaders, hand trucks and wheelchairs. In other words, much like Christensen's work suggested a product such as the Tweel should progress.
"In the end, that is how we entered the market. On turf and construction equipment, and today that's what we sell still is off-road, low-speed unregulated products," Cron said.
By about 2011-12, Cron said it became clear that the Tweel technology was not going to be successful on automobiles. So Michelin constructed a factory to build the Tweel and assemble a team to build on the applications that were successful.
Rhyne and Cron, though, weren't part of that team. They were to stay and work on passenger tire technology.
Michelin told Rubber News it was determined that cars provide a new set of challenges, particularly in providing handling close to pneumatic tires and driving at higher speed. That evolved into what Michelin now calls its Uptis design, which features rubber spokes reinforced with resin-embedded fiberglass.
Having a good part of their careers focused on one technology is a double-edge sword, the Charles Goodyear Medalists said.
Cron said it's good to be able to concentrate on one thing to keep making it better, but then there is a sense of disconnect to other parts of Michelin.
Said Rhyne: "It was very enjoyable, but we had deep roots in the pneumatic tire part of the business ... and that's the main business of the company."
While the Tweel never took over the car tire market as hoped, its inventors are proud of what they did accomplish and the applications where it does shine.
Cron, though, still wishes there had been Tweels made for smaller uses. He pointed out a cart nearby equipped with wheels.
"That thing is a disaster," he said. "If you go over a bump, whatever is on the table will jump off. Plates will break. I know how to make a Tweel for that thing that is so good. Spectacularly good."
Spoken like a deserving recipient of the Charles Goodyear Medal.