Challenge Criterium Open Tubular Tyre is the tyre of choice for many professional road riders the world over. These tyres are extremely difficult to get a hold of and very popular with roadies in the know. The distinctive 'gum' coloured sidewalls add a touch of class to any bike.
These are hand-made foldable 'open tubular' tyres with a very low rolling resistance, for those who demand performance from their tyres.
"Somewhat confusingly, the Criterium (a normal clincher) is called an 'open tubular'. It's handmade for the Italian company and has a 300tpi carcass that's reinforced under the tread with 'resistant fabric'. This provides a level of puncture protection as good as most.
Despite this and the much-higher-than-quoted weight, this supple, file-patterned tyre rolls well: there's little to choose between the Challenge Criterium and other fast, all-round road tyres, such as the Schwalbe Ultremo and Conti Triathlon. As the Criterium name perhaps suggests, it's a sound choice for your road bike, where the high-ish price will be mitigated by peace of mind and decent product lifespan. For time trialling, however, there are seconds to be saved using lighter (and generally less tough) alternatives." - Bike Radar