Pedal Thread Adapter



This adapter provides measurement from the drive-side pedal threads.  Tightening the included nut allows VeloAngle to maintain alignment with the crank arm.


  • Pedal Thread Adapter
  • M8 x 1.25 class 8, zinc-plated serrated flange locknut (13 mm wrench)


  • For 9/16” x 20 pedal threads
  • Adapter wrench flats same as nut (13 mm)


  • Adapter: Machined 303 stainless steel
  • Nut: zinc-plated hardened steel


Arch Design Works, LLC proudly offers all VeloAngle tools and accessories with a lifetime warranty against defects in materials and workmanship. Details can be found in the footer link.


9/16 x 20 is the pedal thread standard for any modern bike for which VeloAngle might be used. Exceptions are some older European bikes. Threads are conventional righty-tighty, lefty-loosey and can only be installed on the drive (chain) side.

In addition to those that prefer measurement from the pedal axis, this adapter is useful for extending the range of VeloAngle’s usefulness. When BB/Handlebar/Saddle measurements less than 648 mm are required, moving the reference point from the crank axis to the pedal thread reduces the effective measurement by the length of the crank arm. This allows VeloAngle’s use on the smallest available adult frames.


Measurement from the pedal with the accuracy requires that the crank arm is aligned with the measurement. To maintain alignment, the included nut can be tightened to clamp VeloAngle to the crank arm. It is recommended that measurement is taken without the chain engaged so the crank arms will move freely.

Fortunately, when the crank arm is fully extended away from the saddle or handlebar, measurement accuracy is not highly sensitive to how precisely the arm is aligned. For example, if the VeloAngle and the crank arm were misaligned by 1 degree (which would be clearly visible) the error on a 900 mm measurement would be 0.7 mm. In fact, some users don’t clamp the tool, but simply move the crank arm back and forth to find the greatest length measurement. The point at which the measurement is greatest is also the point where the tool and crank arm are aligned.


To maintain proper alignment when roating the crank between saddle and handlebar, the pedal thread adapter is best used with the chain disconnected, dropped or with the rear wheel off the ground.