ProBMX Pedal Adaptors - Convert 1/2" Pedal Thread to 9/16" - Pairs

Brand: ProBMX

• Material: Cr-Mo steel
• Colour: Black
• Sold in: Pairs — 1 Left & 1 Right

What This Adaptor Does

These adaptors convert a 9/16" crank arm (larger bore) so it accepts a 1/2" pedal thread (smaller thread). The adaptor sleeves into the 9/16" crank hole and provides a 1/2" internal thread for the pedal spindle to engage.

⚠️ Conversion direction: 9/16" crank → 1/2" pedal spindle. Do not use these in reverse — they will not thread correctly or hold securely.

Before You Install — Check Your Threads

• Crank thread: Measure the crank arm hole. It should be 9/16" (≈ 14.3 mm) diameter. If your crank hole is already 1/2", this adaptor is not required.
• Pedal spindle thread: Confirm your pedals have a 1/2" (≈ 12.7 mm) spindle thread. Most older BMX and kids'-bike pedals use 1/2".
• Thread handedness: Standard cranks use right-hand thread on the drive (right) side and left-hand (reverse) thread on the non-drive (left) side. The adaptors follow the same convention — the LEFT adaptor has reverse (left-hand) thread. Always confirm which side you are installing before threading in the pedal.

Installation Steps

1. Identify left vs right: Mark or confirm which adaptor is left (non-drive) and which is right (drive) before starting.
2. Clean the crank threads: Remove any grease, debris, or old thread-lock from the 9/16" crank bore.
3. Apply grease: Apply a thin layer of anti-seize or waterproof grease to the outside of the adaptor and to the pedal spindle threads.
4. Thread the adaptor into the crank: Hand-thread the adaptor into the 9/16" crank bore. Right (drive) side threads clockwise; left (non-drive) side threads counter-clockwise. Snug to approximately 20–25 Nm.
5. Thread the pedal into the adaptor: Insert the 1/2" pedal spindle into the adaptor. Right pedal threads clockwise; left pedal threads counter-clockwise. Tighten to 25–35 Nm with a 15 mm pedal wrench or 6 mm Allen key (depending on pedal type).
6. Check for play: After installation, spin the crank and confirm there is no lateral wobble or looseness at the pedal interface. Re-torque if needed.

Compatibility Notes

• Designed for BMX and kids' bikes with 9/16" crank arms and 1/2" pedal spindles.
• Not compatible with 3-piece cranks that already have a 1/2" bore, or with adult road/MTB pedals (which use 9/16" spindles).
• Inspect adaptors for wear or cross-threading before each season of use.