Post on this hanger is 20mm (.825") in length with an M12 x 1.75 thread. Please check your hanger before ordering to make sure this is a match.
Trek recommends that you apply a removable thread-locker such as LOCTITE 243 to the retaining nut threads during re-assembly. Failure to do so may result in retaining nut loosening during use. Retaining nut not included.