Well, this past weekend found that our tires (those Vail Sport) had some cracks in the sidewall. They only had about 3 years and 12,000 km on them. Besides the tread was wearing quite bad on them too. Was going to replace them next spring anyway, just had to do it a bit sooner.
Went with some Westlake radial tires (recommended by my tire guy as they have had few if any problems with them), and trust me when I say it was like night and day pulling now. No more wagging back there any more.
Some food for thought!