Originally Posted by Peterpan1

135 is standard on touring bikes. My recent touring frame was a perfect fit for 135. Some custom bikes use 145 spacing for tandem hubs, there is a 165 hub also, and maybe someone will use that some day. The advantage to wider hubs is wider lateral spoke staying base. The strength of the support varies as to the cosine of the angle at the hub. With the 145 hubs, however, these tandem hubs do not necesarilly have wider spacing since they carry drum brakes on the non-freewheel side. So one shouldn't assume every wider hub is an improvement in spoke angle or symetry.