52 millimeters (integrated bearings) or 56 millimeters (internal bearing cups)

Wolf Tooth sells individual parts

300 psi max

46mm OD BB tool (same as Raceface Cinch/SRAM DUB)

Also available in youth sizes

Leatt AirFlex Pro Knee Pads - M - Black PDP|PLP|Brake Rotor Type 52 millimeters (integrated bearings) orThis ultra slim AirFlex knee guard scores a total of 15 points in the Leatt protection rating system. Do not be fooled by these ultra slim knee guards. They offer great impact protection and a slim fit. Our ultra thin 6mm knee pads are CE certified as impact protection. AirFlex series is the slimmest, lightest guards made by Leatt. The new Airflex Pro version now has additional side and upper knee impact protection. For an even slimmer and lighter