don't have to stick with stock specs.
Spreading the rear axle width, lets the hub move to the center line,
so the flanges are equidistant to the center line, and then dishless wheels can be built
140, 145, wide axles are common to tandems.. Shimano's hubs for tandems share 10x1 axle spec ,
so you can modify frame and hub to suit a heavy rider application.

CoMo uses this change on their single touring bikes too..