[BlazingArizona]

120 psi and a very thin wall of rubber = flats. Yes, they could put thicker rubber on, but the weight would be excessive.

I've asked quite a few cyclists about this, and apparently there are urethane-filled tires out there that are pucture proof. So why don't cyclists use them? The urethane-filled tires weigh slightly more, so racers can't use them. But for those millions of recreational cyclists out there on the trails who wouldn't notice few ounces of extra weight, this should be a godsend. So why don't THESE folk use the new tires? The answer I keep getting is that cyclists "won't try anything new". They will spend thousands on every latest quarkonium-unobtainium frame, but they won't invest a little in something that would save them a lot of aggravation.

[olorin]

I ride with kevlar belted tires - two years & no flats.

[RoughDobermann]

I think that you'll find that there is no such thing as a "puncture-proof" tire. Some are better than others, though. Flats are just a part of cycling; always have and probably always will be.

[ironman]

I'm pretty up of bike technology stuff and I'm not aware of any decent solid tires. If people would keep their tires pumped and don't ride them until the treads are showing not many flats will happen. I average maybe one flat a season and I ride 5,000+ miles. Usually it's a piece of glass.