Box Two 35mm Bottom Bracket

Overview

The Box Two 35mm is an oversized bottom bracket engineered for maximum pedaling stiffness and power delivery on modern frames compatible with Box One M35 cranks. This premium component features a massive 35mm spindle diameter, outboard Enduro bearings, and BB30/PF30 compatibility for superior acceleration response and efficiency.

Key Features

• Oversized 35mm Spindle Diameter — Massive cross-section dramatically reduces lateral deflection during hard pedaling; increases bearing contact area and improves power transfer efficiency to the rear wheel
• B52 Technology — Proprietary engineering optimizes stress distribution by reinforcing high-load zones while reducing material in unloaded sections; balances strength with minimal weight
• Oversized Technology™ — Spindle and crank arm interfaces enlarged to accommodate larger bearing rings; increases contact area and stiffness for responsive acceleration
• Enduro™ Precision Bearings — Premium sealed bearings deliver smooth, reliable rotation under high loads; engineered for durability and low friction
• Outboard Bearing Design — Bearings positioned outside the frame shell for maximum support and reduced frame stress; improves overall drivetrain rigidity
• ABS Plastic Sleeve — Protective sleeve reduces friction and wear between bottom bracket cups and frame shell
• BB30 or PF30 Compatible — Fits modern bottom bracket standards on contemporary frames; provides flexibility across different frame designs
• Instant Acceleration Response — Oversized construction delivers noticeable improvement in pedaling response and power delivery efficiency

Technical Specifications

• Type: Praxis M35 oversized
• Spindle diameter: 35mm
• Compatibility: Box One™ M35 cranks only
• Frame shell: PF30 or BB30 only
• Bearing system: Enduro™ precision sealed bearings (outboard)
• Cup material: ABS plastic sleeve
• Weight: 138g (4.9 oz)
• Drive-side seal: Not included

Compatibility & Ideal Use Cases

Compatible exclusively with Box One M35 cranks and frames featuring PF30 or BB30 bottom bracket shells. Not compatible with other crank systems or threaded shells. The oversized 35mm spindle and premium Enduro bearings make this component ideal for riders with modern frames seeking maximum pedaling stiffness and power transfer efficiency. Essential for competitive riders, racers, and those prioritizing acceleration response and minimal energy loss during hard pedaling. The substantial 35mm diameter requires a frame specifically engineered for oversized bottom bracket technology; standard frames are not compatible. Premium pricing reflects advanced engineering and superior performance characteristics.