Ok, put in the 606 value in the "Rim Diameter" box and 18 for "# of spokes this side" and 3 for crossings. I selected fh6401 for column A. I am using openoffice Calc, where should I find the final spoke length?

Also are you sure the measurements are the same for the 6401 and 6400? I have seen different measurements elsewhere for these hubs, then again as both are 7-speed 126mm spacing hubs I couldn't see why they would change the design. The only difference being Uniglide/Hyperglide.

Thanks very much for your help mrrabbit.