Impenenetrable - no.
General answer to a non-flat-prone tire: Continental Gatorskin and Specialized Armadillo. Gatorskin is lighter, rolls easier, and is easier to puncture (but still quite difficult compared to normal tires) than the Armadillo's, which are heavier, a little slower, and harder to puncture.
I run the Armadillo's as my training tire.
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ElJamoquio didn't hate the world, per se; he was just constantly disappointed by humanity.
Last edited by ElJamoquio; 06-17-07 at 06:12 PM.