Tires: Spare, buick roadmaster, proper inflation

Question
Just wanted to mount the spare on my 93 Buick Roadmaster and discovered that the temp tire is a good 6 inches smaller in diameter. I understand the narrower width but can you safely drive 100 feet with this kind of imbalance?

Answer
George,

Obviously GM thinks so.

So long as the differential isn't affected, it's OK.  I'll bet your Roadmaster has an open diff, which means it doesn't care at all, unlike some of the newest AWD vehicles, where the computer senses very small differences and locks the diffs up.

BTW be sure to regularly check the spare for proper inflation - I believe it's 60 psi.

Hope this helps.