Box One Focus 20" Rim 451×17.5mm 28h With Brake Surface

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 rear rim weighs 280 grams and includes a machined braking surface for caliper or U-brake compatibility. Single eyelet construction allows higher spoke tension for improved wheel stiffness and durability.

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

• Machined brake surface – Sidewalls are precision-machined to provide consistent braking performance with caliper or U-brake systems

• 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: 280 g (9.87 oz)
• ERD (Effective Rim Diameter): 438 mm
• Material: 6061-T6 alloy
• Wall type: Double-wall with single eyelets
• Brake compatibility: Rear wheel with machined brake surface (caliper/U-brake)
• Color options: Anodized Black, Red, Blue, Gold

Compatibility and Ideal Use Cases

Designed for rear wheels on 20" BMX race bikes using rim brakes (caliper or U-brake). The 28-hole drilling pairs with standard BMX racing cassette or freewheel hubs for lightweight wheel builds. Best suited for competitive racing where weight savings and reliable braking are both required. 451mm BSD fits standard 20" × 1 1/8" race tires. Not recommended for disc brake setups—brake surface adds weight unnecessary for disc applications.

Note: US orders ship direct from manufacturer and may arrive separately from other items.