Trying to use a 120mm-spaced track hub on a converted road frame?
Instead of being a hack and squeezing your frame together every time you tighten your axle nuts or stacking up a bunch of random washers from your grandad's garage, you're gonna need a couple of these to get the spacing right.
These spacers get securely installed on a threaded axle between your hub's bearing cones or retaining hardware and lock nuts. They are not compatible with hubs that use bolts that thread into the hub (ie: Phil Wood, Mack, Paul, Surly, etc.).