Praxis makes steel and ceramic bottom brackets for road, mountain and gravel bikes. Their popular M30 bottom brackets are compatible with Praxis cranksets that use a tapered 30 mm drive side and 28 mm non-drive side spindle. They also offer a range of other sizes including M30 THRU, 24 mm Shimano, 24/22 mm GXP and DUB. Praxis bottom brackets feature high-quality bearings and forged and machined heat-treated alloy cups.