I am thinking your bike has horizontal drop outs. I have the same issue with a late 80's Ochsner, but the drop outs were not powder coated with the rest of the frame. It is an issue with the horizontal drop outs, the wheel has a tendency to be pulled forward on the drive side due to the torque from the chain. As stated above, good internal cam skewers are needed, and you still might have to tighten them down more than you would with vertical drop outs. When I spread the rear to 130mm, I put on a set of Open Pro/Ultegra wheels with Ultegra QR's, internal cam, and the wheel does not slip as long as it is tightened enough, which is far less than the old ones. I could hardly open those after tightening them so much. I have an older set of Bontrager wheels and QR,s, not internal cam, they will slip on the Ochsner, but not on a bike with vertical drop outs.