Box Two External Sealed 30mm Bottom Bracket Product Overview The Box Two External Sealed 30mm Bottom Bracket is a sealed cartridge system designed specifically for Box One M30-M and Box Two M30-P cranks. Built from 6061-T6 aluminum with sealed bearings, it resists contamination and extends service life in varied riding conditions. The 30mm axle diameter provides the stiffness required for responsive pedaling feel. Key Features External sealed cartridge design — Bearing cartridge sits outside the shell, protecting internals from dirt, mud, and water while allowing straightforward bearing replacement Sealed bearings — Reduces maintenance intervals and prevents premature wear from moisture and abrasives 6061-T6 aluminum construction — Offers a balance of weight and durability with proven resistance to repeated impacts 30mm axle diameter — Larger diameter increases lateral stiffness compared to smaller axles, reducing flex under load BSA threading — Standard 1.37" x 24 TPI thread pattern ensures compatibility with most BMX frames Technical Specifications Weight: 110 grams (3.9 ounces) Material: 6061-T6 aluminum Shell width: 68mm Thread standard: 1.37" x 24 TPI (BSA) Axle diameter: 30mm Bearing type: Sealed cartridge Crank compatibility: Box One M30-M and Box Two M30-P only Compatibility and Ideal Use Cases This bottom bracket is exclusive to Box One M30-M and Box Two M30-P cranksets and will not work with other manufacturers' cranks. Ideal for riders upgrading from worn original hardware or building a complete drivetrain with Box components. Recommended for street, park, and racing applications where sealed protection against weather and dirt is valuable. **Due to unique nature of this item, ALL sales of this product are FINAL. No Refunds or Returns**
