Wheels Manufacturing T47 Inboard Bottom Bracket 24mm Spindles ABEC-3 BearingsWheels Manufacturing T47 Inboard Bottom Bracket for 24mm Spindles with ABEC 3 Bearings. T47 Inboard threaded bottom brackets are made from machined aluminum and thread together directly into T47 frames. Cups have internal bearings for use in BB shell widths from 68mm to 132mm. Enduro Angular Contact bearings easily serviced or replaced Similar to standard BSA threaded cups; the drive side cup is left hand thread and the non drive side cup is right