Fox Suspension CSU

This assembly is a single, factory-pressed unit that includes the fork crown, the steerer tube, and the upper stanchion tubes. It is designed to replace the entire upper structure of your fork rather than individual components.

You must match the stanchion diameter, travel length, and steerer tube specifications exactly. This unit is specifically for forks with 38mm stanchions, 180mm of travel, and a 1.5-inch tapered steerer tube; it will not fit forks with different dimensions.

No, the crown, steerer, and stanchions are pressed together at the factory to ensure precise alignment and structural safety. Attempting to disassemble or replace individual parts of this unit compromises the fork's integrity and is not recommended.

While the installation is straightforward, it requires specific tools for removing the old CSU and pressing the headset race onto the new steerer tube. If you are not comfortable working with suspension internals or lack a headset press, it is best to have a professional mechanic handle the installation.

You typically replace a CSU if the stanchions are scratched or worn, causing oil leaks that new seals cannot fix, or if the steerer tube has been cut too short or damaged. It is also the necessary fix if there is creaking coming from the crown area, which indicates the bond between the stanchions and the crown has failed.