Bicycle frame: rigid or suspended; minimum wheel diameter 26" (66 cm), max 29" (74 cm); 27.5" and 29" dominant in pro XCO; Hydraulic disc brakes required at UCI level (front + rear); Handlebar width limited to 1000 mm max
Why people argue about this
People often assume that hydraulic disc brakes are a choice for UCI Mountain Biking based on their effectiveness, but actually, they're mandated by the rules as a key safety feature at this elite level to ensure fair competition and prevent dangerous accidents. The confusion arises because many riders initially see them as an optional upgrade rather than a required piece of equipment.
