I have a stash of rims that came from Spence Wolf, including some 48 hole Super Champion Mod 58 versions. Spence talked Phil Wood into making sealed bearing hubs, the version I just modified were what he came up with. I am pretty sure that Spence ordered Super Champion (Wolber in France) rims in 48 holes for use on tandems. 48 hole wheels have a very small chance of spoke breakage, unless a stick falls in the wheel when riding! Jim Merz