Ford Focus Forum : “abnormal tire wear”

not that i've noticed. my 05 is fine, usually just get nails in my tires.

Get your alignment checked, and be sure to rotate your tires every three to six months, depending on how much you drive.  Also, be sure they are properly inflated.  Basic car care.

Excessive negative camber combined with Toe-out can increase wear on the insides of your tires. Mind you a little toe-out is required on front drivers like ours. The idea is that the driving wheels (front) will pull straight under power due to the compliance of the suspension bushings.

check your alignment and your tire pressures regularly and rotate every 10,000 miles.

or the springs are broken like in most ford focus after a while thus giving u a unnoticeable lower stance and throwing your camber out.

Ford has updated specs for those years. (Less positive toe in rear) Also longer replacement upper control arms available for rear if yours has a problem with excessive negative rear camber.