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These lower headset cup extenders allow you to adjust the geometry of your bike frame by increasing the effective fork length by 10mm. They allow you to do things like use a rigid fork on a suspension-corrected frame or use a fork with a shorter axle-to-crown height rather than what the frame was designed to use. They can also be used to increase the bottom bracket height and lower the headtube angle.

Wolf Tooth Precision Headsets are machined in the USA out of aircraft-grade 6061 aluminum with superior sealing for protection against the elements. These ZS headsets are for frames with internal bearing cups that are pressed into the frame.


  • Any frame that uses a zero stack headset with a 56mm lower head tube inner diameter
  • Upper and lowers headsets sold separately 
  • Enduro stainless steel sealed bearings included

Lower assembly features:


The Wolf Tooth crown race installation adapter will help avoid damaging the crown race seals

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Tech Specs

Weight: 62g
Material: 6061 aluminum cup, stainless steel bearing
Includes: Cup, bearing, and race

Made in the USA

Patent and trademark information

WARNING Handling this product will expose you to chemicals, including lead, known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling. For further information go to