Wide spread titanium-toothed cassette
Sprocket Cluster / Cassette
Clever ceramic/aluminium one-piece gearing
Lightweight nine-speed cassette
Staggeringly lightweight cogs
For 2008 the only change to the Centaur sprockets is the addition of 'macro' spacers
While not strictly part of the Tiagra line, this all- steel cassette would usually accompany this groupset, though you can save weight by fitting the 9-speed version of the Ultegra cassette that uses an aluminium cradle and costs £32.95.
The SRAM OpenGlide cassette uses an aluminium holder that retains steel cogs and is a radical design that omits one tooth on every cog to aid smooth shifting. We experienced an intermittent problem with chain