Spoke wrench

Spoke nipples are typically T-shaped in cross section, with an internal thread running part of the way through the hole that runs along the spoke nipple's principal axis.

However, unlike a typical nut-and-bolt pair, a spoke and nipple do not join two parts (the rim and the hub) so much as bridge them, under tension.

The area of the nipple around which the spoke wrench, or key, is fitted is generally square in cross-section.

The act of shifting over the centerline of the rim between axle locknuts is referred to as dishing the wheel.

By increasing or decreasing the tension of individual spokes, or groups of spokes, around the circumference, a wheelbuilder or bicycle mechanic can correct for local deviations from true – e.g. wobbles, or hops.