Replacing tire subaru forester

I believe Subaru requires the tires to be within 1/4" circumference or 2/32" tread depth. In the tire industry it is considered safer to put the new tires on the rear.

OMNG! You're BOTH wrong! The AWD sustem simply wants equal rolling radii. Because Subarus are typically 60/40 F/R weighted, the front tires run a little faster than the rears. I compensate for this by advising clients to run 35-36/F and 32-33/R psi, to get closer to identical radii. The WORSt things one can do is to put wildly different heights on one axle, or almost equally bad, put NEW (taller) tires on the REAR, further upsetting the attempt to create equality. So if you need to replace a bad tire, get a NEW pair for the front, put two of the used on the rear, and keep the remaining good one as a 5th tire. Always put the weakest tread on the right rear, where weight is usually the least of all corners. Do this and you'll be fine. The reasons dealers and tire shops tell you not to mix tires and force you to buy 4 tires are obvious. Generally, with Subies, one tire cross-rotation midway through tread-life will both reverse any cupping, as well move the taller tread up front. Eventually you'll wear the set out fairly evenly and start with 4 new ones. But adding fresh pairs to the front only is an equally valid plan. Just NEVER put the taller tread in the rear. If you;'re mixing brands and are not sure, roll one mounted and pressurized tire of each brand up to each other and carefully eyeball (or measure) their heights...always putting the taller ones up front. Other vehicles that have a nice 50/50 weight balance of course aren't so fussy. Keep well and safe.

"exactly that" what? I've sold about 2000 AWD Subies in my career, always placing stronger tread up front, and then advising clients to mount new pairs as needed up front if they've ruined one tire. NEVER has anyone subsequently blown up a transfer case. This ONLY happens when folks put new or taller tires on the REAR, further stressing the AWD system via unequal rolling radii. The first true AWD systems debuted with the 1990 Legacy, and are in essence to this issue unchanged for 30 years. The transfer case can absorb a fair amount of disequilibrium; otherwise you wouldn't be able to go around corners nor park them easily. So explain EXACTLY what your D-i-L did?

I think Ernie is pointing out a distinction without a difference. The way your get equal circumference or radius is to have all the tires the same size. Sam ting either way you look at it.