I was talking to a guy at an LBS yesterday that raves about Stans. He's got a Ti Spot, belt driven SS with the Maveric Duc (?) fork on it and it must weigh 20 lbs. Anyway, I told him about your issue and he said it's the side walls on 29er tires. You need to get a set of tires with stronger ones. He uses Schwables (wasn't the German WWII ME 262 fighter jet called the Schwable?) Anyway, don't remember what you were using for tires but take them back to where you got them and ask for a replacement or refund.