Internal nipples hide inside the rim where standard spoke wrenches can't reach them, and the Park Tool SW-18 is built specifically for that job. The slim profile slides through the spoke hole in the rim bed, engaging the nipple from above rather than from the side. It's a simple tool that solves a real problem—without it, you're either fighting with pliers or accepting defeat on wheels that use this construction.

The 5.5mm square socket fits the internal nipples found on many aero and carbon road wheels, where manufacturers route spokes through the rim cavity to eliminate external nipple drag and clean up the rim profile. DT Swiss, Zipp, and several other wheelmakers use this style on their deeper-section offerings. The knurled handle gives you enough grip to apply tension without slipping, and the overall length provides clearance to work through rim depths up to about 60mm.

If you're building or truing wheels with internal nipples, this wrench is non-negotiable—there's no substitute tool that works. The socket engagement is precise enough that you won't round off nipples even when adding significant tension during a build. For wheels with shallower rim depths, the same internal nipple might be accessible with a standard wrench from below, but deeper rims absolutely require the through-rim approach.... Read More