F-Stop Dimension

  1. M12 X 1.5


All MASON products are designed to be durable, serviceable so our unique 'F-Stop' axle system features these replaceable inserts which can be swapped out if the threads are stripped or worn.

MASON F-Stop Inserts have been developed as part of our 'F-Stop Axle System' which allows for various axle fitments in a fully serviceable and customisable axle system. We introduced this system with our Aperture2 fork. Click HERE to find out more about our progressive fork designs.

F-Stop inserts are 3D-Forged and feature a taper-fitment to ensure precise location and easy axle insertion. They're also reversible so you can mount them to either fork dropout to choose where your Thru-Axle lever is positioned.

F-Stop inserts are sold in pairs and available in M12 or M15mm versions. Supplied with 1 X M3 CSK screw per insert.


  • Available in M12 x 1.5 / M15 x 1.5.
  • Replaceable and reversible threaded/non-threaded inserts.
  • 3D-Forged and Anodised alloy.
  • Supplied with 1 x M3 CSK Hex screw.