RockShox SID CSU

The CSU (Crown, Steerer, and Upper tubes) is a single, integrated unit. It replaces the entire top section of your fork, including the crown, the steerer tube that inserts into your frame, and the upper stanchion tubes that slide into the lowers.

This assembly is designed specifically for RockShox SID Ultimate forks from 2020 and newer. You must match the stanchion diameter (32mm), wheel size (29" or 27.5"), and offset (42mm) to your existing fork chassis to ensure a proper fit.

RockShox manufactures the CSU as a permanently bonded unit for structural integrity. If your stanchions are scratched, bent, or the steerer tube is damaged, replacing the entire assembly is the only way to restore the fork's original alignment and safety.

No, this is strictly the CSU assembly. It does not include the lower legs, air spring internals, damper, seals, or bushings. You will need to transfer those components from your current fork or purchase them separately.

Replacing a CSU requires specialized tools, including a crown race puller and a press for installing the new crown race. If you aren't comfortable with advanced suspension service, it is best to have a professional mechanic handle the swap to ensure the steerer tube is cut correctly and the assembly is safely installed.