Surly Trailer Hitch Axle Stud Bolts: Replacement for Hitch Mount Nuts Pair. These are hitch mounts are for connecting Surly Bill and Ted Trailers to any 10mm x 1mm solid axle. They replace standard locknuts. They also include threaded stubs for direct mount to Surly Troll Ogre and ECR frames – these frames have eyelets drilled into the dropouts specifically for these mounts.3/8" x 26tpi mounts not currently available