Have they taken a look at the rim? I have a set of velocity diads that would not play well at all with a set of maraton XR tires. turned out to be the inside lip of the rim, the hook was sharp as a razor and would pinch the tube between the rim and the tire. Before I fixed it with some sandpaper I was inflating the tires with ear protection on. It took me more then a couple of tubes to figure it out, easy to look back and laugh at it now. the thing was that this only happened with the XRs. Looking at the cut along the bead, I suspect the rim may be playing a part in this.