Here is the result of my latest experiment I build dishless wheels using ordinary Shimano hubs. This axle has 16000 miles on it with 165 pounds on the rear wheel. It is pitted and smashed. The shimano hubs with wider bearing placement the tandem and 6 bolt brake hubs reduce the chances of a bent or broken axle so you can expect them to fail in this manner. This seems to be the weight limit for these hubs with higher weight or more mileage you should upgrade to a hub without axle threads. You should also upgrade if you have an aluminum frame. My Cannondale single only lasted 6000 miles before the axle destroyed the dropouts.