95 Legacy LS:

 

Can a full size RE 92 Bridgestone tire replace a doughnut tire? or do I need a matching rim to go along with it?

Just had a look at mine and the doughnut rim looks much skinnier than the standard rims.

My '93 Leg has a 135/70 R14 spare. YOu could mount the larger tire on that smaller rim (they are 185/70 R14 for mine, yours are probably different) but, as Gilles points out, that narrow rim means more flexion stress at the tread/sidewall junction which increases the likelihood of a blowout. Also, the bead will probably not sit too well since it is designed for a wider rim.

 

Do you want to use a full size spare on this vehicle? You may not be able to fit it in the wheel well and still have a flat cargo space floor as the space is designed for the compact. JM $0.02 here

The issue is that we all know better than to drive a Subaru AWD with a doughnut. That leaves many of us searching for a matching 5th rim. I was wondering if I can use a full size spare tire I have on the doughnut rim. Is that an acceptable solution or we better of finding a matching rim?

 

My .02 cents. Subaru should either do the right thing and provide a full size spare or bite the bullet and charge the additional money for the full size tire.

 

Are you listening Subaru? Not everyone reads the book.

Find a rim in junk yard. I'm not sure, but I think you'd have a hard time finding a tire shop that will mount a full size tire on a rim with that slim of a profile. There also may be inside clearance problems with a real tire on that rim.