You'll definitely need a rim, some spokes, nipples, a hub and a spoke key. You'll also benefit from a wheel building jig, a dishing gauge and a nipple driver, although it is possible to build wheels without them. Here, we're building a nice, simple set of 451 wheels with large-flange track hubs and V-section double-wall rims. The spokes here have already been cut and threaded to the correct length. Spoke length is dependent on many variables, and is worked out with a calculator chart. One problem with 451 wheels is that stock spokes are not readily available in the appropriate length, as they are longer than BMX (406 size rims) spokes but shorter than MTB (559 size rims) sizes. Spoke length must be correct to the millimeter. Here, because front and rear hub flange dimensions are identical and dish is symmetrical, all spoke lengths are equal at 200 mm. However, it's not unusual to need three different spoke lengths in a single pair of wheels if hub dimensions, dish, spoke count or pattern varies.