Box Two External Euro 24mm Bottom Bracket

Overview

The Box Two External Euro bottom bracket is a sealed component engineered for compatibility with Box Three and Four cranks on single-speed and multi-speed BMX and freestyle bikes. Cold-forged and CNC-machined aluminum cups combined with dual-labyrinth bearing covers and precision sealed bearings deliver reliable performance and extended component life.

Key Features

• Cold-Forged and CNC-Machined Cups — Precision-manufactured aluminum construction resists deformation and wear; ensures consistent bearing support and smooth spindle rotation
• 6061-T6 Aluminum Construction — Aerospace-grade aluminum provides strength and corrosion resistance; reduces overall bottom bracket weight compared to steel alternatives
• Dual-Labyrinth Bearing Covers — Labyrinth sealing system sheds water and mud while preventing dirt infiltration; ideal for riders in wet conditions and casual outdoor use
• Precision Sealed Bearings — High-quality sealed bearings reduce friction and extend component life; minimizes maintenance requirements
• 24mm Crank Spindle Compatibility — Engineered specifically for Box Three and Four cranksets; ensures optimal fit and reliable power transfer
• Universal Shell Compatibility — Fits both 68mm and 73mm × 1.37-inch (English) threaded bottom bracket shells; accommodates various frame geometries
• Upgrade Component — Significant improvement over budget bottom brackets commonly included with cranksets; delivers superior durability and smooth operation

Technical Specifications

• Type: External Euro bottom bracket
• Shell width: 68mm or 73mm
• Thread size: 1.37 inch × 24 TPI (English)
• Axle diameter: 24mm
• Cup material: 6061-T6 cold-forged and CNC-machined aluminum
• Bearing system: Precision sealed bearings with dual-labyrinth covers
• Weight: 105g (3.7 oz)

Compatibility & Ideal Use Cases

Compatible with Box Three and Four cranks and frames featuring 68mm or 73mm × 1.37-inch English-threaded bottom bracket shells. Ideal for BMX cruisers, freestyle bikes, and single-speed builds using Box cranks. The sealed bearings and labyrinth covers make this component well-suited for casual riders and those in wet climates seeking reliable, low-maintenance performance. An essential upgrade from stock bottom brackets for riders prioritizing smooth rotation and component longevity. Not compatible with press-fit or metric-threaded shells.