Tapered Steering Knuckle Inserts An excellent option when using a larger GM 1 ton taper (.75" large end of taper, .68" small end) without buying an expensive tapered reamer. All you need is a 7/8" drill bit, drill your knuckles to 7/8" bore and drop these in. Can be used for either over the knuckle or under the knuckle steering. You will need 1 insert per tie rod end to complete your steering installation. Note For use with our GM 1 Ton TRE's only!