Originally Posted by
Retro Grouch
24 or 28 hole I lace 2 cross. 32 and 36 hole I lace 3 cross.
Me too, generally. Exceptions are wheels with very large flange hubs (think "Rohloff") and/or small rims (think 20" or smaller.)
There are two main issues:
Excessive crossing can cause excessive angles where the spokes enter the nipples.
Insufficient crossing of wheels that experience torque loads (rears, fronts with hub brakes) can lead to spoke or hub flange breakage.
The issue there is the "moment arm" of the spoke. If you don't remember this concept from high school physics, imagine the spoke lines extended inward until they cross the middle of the hub. The moment arm is the distance from this line to the axle centerline, at closest approach.
The smaller the moment arm, the greater the torque related stress on spokes and hub flanges. The extreme example is radial spoking, where the moment arm is zero, since the spoke's line runs straight through the axle.
I must admit a bit of fondness for radial and other oddball spoking for
front wheels. Most front wheels are rather overbuilt anyway.
Sheldon "Spox" Brown