• Thread insert:Trek Domane Disc thread insert, M12x1.5mm internal thread, M20x1mm external thread (replaces original). This kit will ONLY fit the Trek Domane Disc 15x100 disc fork. Installation instructions: Use 1" (25.4mm) spanner wrench to unscrew nut on disc side of fork then push original threaded insert out of hole, or tap it out using a plastic mallet.