I have a set of Sumitomo HTR H4 tires on my 2003 Elantra. The tire is rated at 60k, but I only have about 33k on them and they're almost gone. I expect to replace them around 38k. The car came with Michelins which were rated at 50k and I actually got 45k+ from them before getting the HTR H4's. I'm wondering why the Sumi's are doing so poorly? I've had them rotated every 5k. Alignment seems fine - no pulling when driving and no feathering on the tread. The tires are wearing pretty evenly except for the center having a little more tread then the outside (probably due to periods of under-inflation). Fortunately they will be prorated when I replace them so I will recover some of the investment, but I'm wondering if I should be looking at a different tire/brand? Any thoughts?