Years ago, I bought new Goodyear tires for my 98 Dakota truck. After a short while, it started pulling hard to the left. First thing I thought of was a tire problem. It had NEVER pulled before. The tire shop tried really hard to sell me all new ball joints, tie rod ends, etc. I had just done that about a year ago. I insisted the manager go for a drive around the block to see how hard it was pulling. Then we got back to the shop and I insisted they swap the front tires and that the manager go around the block again. Wow, now it pulled hard to the right. They appologized and gave me two new tires. I am no tire expert, but I guess that a separated belt in the tire can do that. it will increase the rolling resistance.