Had a flat yesterday, tires are pretty new <10Kmiles on them, very little thread wear. thinking on replacing only that one.

tirerack says the full thread depth spec is 10/32", I measure 9/32" with my caliper.

Searched the owner manual and found no mention that it may damage AWD?

IIRC for my previous 02' and 2010' Legacy there used to be some acceptable tolerance on the tire diameter difference, but see nothing here?.

 

Is the difference in tire diameter (circumference) no longer an issue with the new AWD drive for this MY?

 

-Michael

It was always 1/4" circumference on the older models.

You should be fine to get just one tire. Put it on the front left.

Yes, 1/4" circumference is  how I remember and it was always in the manual, this 2014 does not list it. Why front left?

LF is most likely to wear the fastest, therefore it will catch up to the other three quicker.

Called a dealer service department, they said as long as the thread is "good" it's OK to replace just one tire but it has to be the same brand/model. Looks like the newer AWD system can tolerate diameter/circumference differences that are as large as whatever is due to the thread wear over the tire lifetime?