The zipp 900 disc remains one of the lightest stiffest disc wheels in the world and was still more than fast enough to help american cycling legend kristin armstrong to time trial victories galore at just 935g with a cassette hub the 900 is light enough for the hilliest triathlon or time trial courses zipp was founded 20 years ago to produce carbon fiber discs that were lighter and faster than anything else available at the time today the 900 still reflects that commitment to giving you