Originally Posted by
davester
Another reason to go with different lengths is that on the back wheel it makes sense to go with sturdier, thicker spokes on the drive side and lighter on the non-drive side so as to decrease the tension asymmetry associated with a dished wheel. This means that you'll be ordering a different spoke type for the drive side anyway, so why not get a different length. There really is zero reason to use same length spokes for the rear as for the front.
Interesting post but there are many levels to that line of analysis. What we really want is to minimize the cumulative fatigue damage. This typically occurs in the elbow of the spoke. Obviously, the weakest link are the drive side spokes on the rear wheel. For these I would recommend
butted spokes of material of the highest ultimate tensile strength available, that is, if you want to get anal about it.