So, after filling up on gas today, I noticed a rather noticeable bulge in the sidewall of my front right tire. Parked my car, checked all the tires and there's also a slight bulge in the rear right. I'm currently running BF Goodrich G-Force Super Sport all seasons. I got a set of 4 back in the summer of 2010, and replaced one tire 2 weeks later due to a nail in the sidewall. 6 months later, I replaced the entire right side, due to a pot hole. Now, it appears as if the right side is about to go again, given these bulges. I think they're the 2 tires that were most recently replaced (about 1, 1.5 years ago), so I'm wondering if I could get it replaced under warranty, given that it may be a manufacturers defect? I check my pressure every other week, and inflate to the correct pressure (compensating for the temperature) when necessary. But, given my car is AWD, I would need to replace all 4 tires anyways. If I were to get tires replaced under warranty (which again, I'm not sure if I can), I would need to buy another 2. If I can't get it replaced by warranty, or if I would decide to do otherwise, I can buy 4 new tires. My tire size is 215/45ZR17 91W... they're not cheap. I use all seasons, and so far, I'm between the Continental Extreme Contact DWS, and Kumho Ecsta 4x, which both seem to be good tires for the money. Any other suggestions?