Tires
 

I own a 2008 4runner SR5 (50k miles) with P265/65R17 110S tires (Michelin cross terrain with 50K miles on the front and Toyo open country with 10k miles on the rear)
When driving on the pavement with the slightest grooves (from studs) the car wanders a lot (like herding cats). What's my problem? Is it the tire size? Tire wear difference?