TZMN DVL

Want to chime in here, as I've had a similar experience. Picked up a '13 Touring 6MT about a year ago. Came with Yokohama Advan Sports all around, but the rears were new Advan Sport *All Season* (UHP A/S) put on by the dealer, while the fronts were half-worn Advan Sport *Summer* tires. Was aware of this when I bought it, but it took me a few months to get around to replacing the front tires. During the mismatch, the car was generally unpleasant to drive. Would constantly pull me around in the lane. Not fun, and sometimes, pretty unnerving. Once I replaced the fronts with matching Yoko Advan Sport All Seasons (UHP A/S), it was like night and day difference.

I've read that summer tires are more prone to tramlining (following generally invisible grooves in the road) than all seasons, and I think I've heard that shorter wheelbase cars may be more prone to this. I've never had summer tires before so I can't speak to that. I'm not sure if the mismatch between half-worn summers up front and new all seasons in the rear was my issue, or if it was just how summer tires are, but replacing the fronts made all the difference for me. Car now tracks straight and handles predictably.

Are you sure you're on matching tires? My car had Yoko Advan Sports all around, so, based on a casual inspection, you might think they're a matching set, but in my case, they were not. Just want to throw this out there, as it had a significant impact on how my car tracks and handles.