Rock The BB Precise fit, smooth-rolling operation, long-living performance-what more can you ask for from a bottom bracket? Install a 30mm CINCH crankset friendly PF30 and get riding...and keep riding. Rolling deep The PF30 bottom bracket uses reliable 6806 retainer bearings packed with waterproof grease, along with wiper seals to keep the gunk out. Close Enough Won't Cut It We fired up the ol' CNC machine to make sure the anodized 30mm alloy cups of this bottom bracket provide an exact, perfectly quiet fit for your frame. Weather, Or Not All RF bottom brackets come with an inner plastic sleeve to keep the elements out and the appropriate spacers to ensure a perfect fit.