Box One Focus 20" Rim 451×17.5mm 28h

Product Overview

The Box One Focus is a lightweight double-wall rim designed for 20" BMX racing wheels. Built with a low-profile extrusion that removes excess material, this 28-hole rim weighs 244 grams while maintaining structural integrity through single eyelet construction. Intended for disc brake or brakeless setups only—no braking surface is machined into the sidewalls.

Key Features

• Double-wall construction – Inner support wall distributes spoke tension and impact loads across the rim structure for improved strength-to-weight ratio

• Single eyelets – Metal inserts at each spoke hole resist spoke pull-through under high tension, allowing tighter wheel builds without rim failure

• Low-profile extrusion – Minimized material in non-structural areas reduces rotational weight without compromising lateral stiffness

• No brake surface – Sidewalls are not machined for rim brakes, reducing weight and eliminating unnecessary material for disc brake or coaster brake applications

• ENBMX compliant – Meets or exceeds European BMX standards for race rim performance and durability

Technical Specifications

• Rim size: 20" × 1 1/8" (451mm BSD)
• Internal width: 17.5 mm
• Spoke holes: 28h
• Weight: 244 g (8.6 oz)
• ERD (Effective Rim Diameter): 442 mm
• Material: 6061-T6 alloy
• Wall type: Double-wall with single eyelets
• Brake compatibility: Disc brake or brakeless only (no rim brake surface)
• Color options: Anodized Black, Red, Blue, Gold

Compatibility and Ideal Use Cases

Designed for front or rear wheels on 20" BMX race bikes using disc brakes, coaster brakes, or freecoaster hubs. The 28-hole drilling pairs with standard BMX racing hubs for lightweight wheel builds. Best suited for competitive racing where weight savings are prioritized and rim brakes are not used. 451mm BSD fits standard 20" × 1 1/8" race tires. Not compatible with caliper or U-brakes—disc brake mount or brakeless hub required.