Things to know when building wheels - Hub edition

This is a measurement, in millimeters, between the center of one spoke hole to the center of another spoke hole on the opposite side of the same flange. Since it is difficult taking an accurate measurement from the center of a hole, it may be more accurate to measure from one edge of the hole to the same edge on the opposite hole. Use metric measuring calipers for the best results.

Hub center to flange is the distance in millimeters from the hub's center to the flange. This measurement is essential for calculating spoke length and ensuring proper wheel build.

This is the diameter of the actual spoke holes in the flange. The default value of 2.5 mm works fine for most hubs. Hub spoke hole diameters range from 2.0 mm to 3.0 mm. Some higher quality hubs have smaller spoke holes so to achieve the ultimate in accuracy the default value can be changed.

This is the total number of spokes in the wheel, even if you are calculating spoke lengths for only one side of the wheel.