BOX TWO STEM SPACERS 1-1/8"

Product Overview

The Box Two Stem Spacer Kit is a set of CNC-machined aluminum spacers designed to adjust stem height on BMX bikes with 1-1/8" steerer tubes. Extruded from 6061-T6 aluminum with a lightweight design, these spacers allow precise handlebar height adjustment by stacking between the headset and stem or above the stem on the steerer tube. Each kit includes five spacers in different thicknesses for a total adjustment range of 1mm to 20mm.

Key Features

• 6061-T6 aluminum construction – Extruded and CNC-machined aluminum alloy provides strength while keeping weight minimal
• Multiple thickness options – Kit includes 1mm, 3mm, 5mm, and 10mm spacers that can be combined for precise height adjustment
• Lightweight design – Weights range from 6.7g to 8.2g depending on spacer thickness
• 1-1/8" steerer tube compatibility – Standard size for modern BMX headsets and forks
• 22.2mm handlebar compatibility – Spacer inner diameter also fits standard 22.2mm (7/8") handlebars for bar-mounted spacer applications

Technical Specifications

• Material: 6061-T6 aluminum, extruded and CNC-machined
• Steerer tube size: 1-1/8" (standard BMX/MTB threadless headset)
• Spacer thicknesses included per kit:
  • Two (2) x 1mm spacers
  • One (1) x 3mm spacer
  • One (1) x 5mm spacer
  • One (1) x 10mm spacer
• Total adjustment range: 1mm to 20mm (when stacking multiple spacers)
• Weight: 6.7g to 8.2g per kit (varies by spacer size)
• Sold as: Pack of five spacers

Compatibility and Ideal Use Cases

These spacers fit BMX bikes with threadless headsets and 1-1/8" steerer tubes—the standard for modern BMX forks. Not compatible with threaded headsets (older BMX bikes with quill stems) or 1" steerer tubes. The spacers stack on the steerer tube between the headset top cap and stem, or above the stem to raise handlebar height. Verify your bike uses a threadless headset and 1-1/8" steerer tube before ordering.

Best suited for riders who need to adjust handlebar height for fit, comfort, or riding style preferences. Stack spacers below the stem to raise the handlebars, or remove spacers to lower them (note: lowering requires cutting the steerer tube shorter or flipping spacers above the stem). The multiple spacer thicknesses allow precise height tuning—for example, use both 1mm spacers plus the 5mm spacer for a total of 7mm adjustment. Ideal for dialing in cockpit position during bike setup, accommodating rider growth, or adjusting bar height for different riding styles (higher bars for cruising and comfort, lower bars for racing or aggressive riding). Important: The steerer tube must extend through the stem with at least 3-5mm of tube protruding above the stem top for proper headset preload. If adding spacers causes insufficient steerer tube protrusion, you cannot safely add more height without a longer steerer tube. The 22.2mm inner diameter also allows these spacers to be used on handlebars for applications like raising brake lever or grip position, though this is less common.