Spoke Length Calculator
What is Spokcalc?
Spokcalc is a free Mac OS X (and 9) program I made that calculates spoke lengths for wire spoked wheels. Spokcalc includes a database of over 400 hubs and 550 rims. The Spokcalc database is also user-modifiable and -expandable so you can add more rims and hubs.
Instructions for using the
Here is some more information regarding the inputs to the calculator. All measures are in mm.
Total Spoke Number - This is the easy one. The total number of spokes to be used.
Effective rim diameter - This is the most important measurement to get correct. It is the diameter of the rim as measured from the end of one spoke nipple (the end inside the rim) to the end of the nipple in the hole exactly opposite to the first.
Flange width to center - The distance from the center of the hub to the center of the flange. The center of the hub is 1/2 of the measure between the outside of one lock nut to the outside of the other. Then measure from the outside of the lock nut to the center of the flange and subtract this measurement from the first. If the hub is asymmetrical (such as a rear hub) you will need to run 2 calculations, one for each side.
Flange diameter - The distance from the center of one spoke hole in the hub to the opposite spoke hole.
Spoke hole diameter - Probably the least important measurement to measure precisely. The diameter of the spoke hole in the hub.
Crossings - The number of spoke crossings in the lacing pattern to be used.