When is it necessary to replace the saturated test ring with grease for CPTu tests? December 06, 2025 14:34 Updated The test ring with grease must be replaced together with the tip and the lateral friction sleeve. Related to CPTu Piezocone Related articles When is it necessary to replace the tip (Qc) and the friction sleeve (Fs) of the piezocone? Is it still possible to repair the TGAS-08 data-logger? What is an encoder and what is it used for during CPTu and S-CPTu tests? During the test, the "tilt" value steadily increases When is it necessary to replace the porous filter for CPTu tests?