Campagnolo uses a hollow axle and light alloy cups/spacer with three cartridge bearings supporting the spindle. This bottom bracket is lighter and stronger than the Veloce model. 115.5mm is for use with triple cranks with 34.9/35.0mm seat tubes. For seat tubes smaller than 34.9mm, use the 111mm Centaur (#0205). Use Park's BBT-5 (#2489) for installation.