Originally Posted by
rpenmanparker
The reason lower TPI casing is offen more puncture resistant is likely that the structure is much thicker and heavier. I agree with Lazyass that higher TPI is inherently more pincture resistant thsn lower TPI, all else equal. So if you have a low TPI casing and a high TPI both with the same total amount of fiber, the higher TPI casing should be much more puncture resistant. Problem is, high TPI casings are usually found in the lightest tires and the effects offset each other.
Right. I don't know much about the actual construction of tire carcasses, but I had a high (290?) tpi pair of Vittoria Corsa Evo clinchers that felt fantastic but flatted constantly, like every 3rd or 4th ride, and would gash with sharp rocks that would bounce off other tires. Super light, but no flat protection.
Lower TPI tires like Gatorskins (180, I think) have belts of kevlar or somesuch woven into the thicker tread. They may not have as much grip or the "supple" feel everyone's talking about, but there's no question they last longer and offer much better puncture protection against the usual things you find on roads like glass shards and metal wires.