Huh, really? I’m another guy who rides thousands of miles a year (I’m sitting at about 2,100 right now, and for me that’s behind schedule thanks to shoulder surgery over the winter), and I’ve never had this happen. Is it actually causing the valve to rupture and make the tire go flat, or just angle the vale and scuff up the outside? What kind of valve is this, shrader or presta? And how recent are the bikes?
I really don’t know what to suggest here - is the tire seated properly on the rim? Are you, like, lubing the rim or something? Idunno, man, that one’s a first.