A disk brake compatible update of the original rear rack design where it all began for Blackburn in 1975 Mounting system works with disc brake frames and bikes lacking rear dropout rack mounts Lower mounting points attach to included extra-long QR skewer Three strut design for maximum load control 12mm gauge aircraft-grade aluminum rod ensures long lasting durability Fits both wide and narrow tire Fits 26" and 700c frames Compatible with Copilot child seats 535 grams 40lbs/18.2kg carrying capacity