Different wheels sizes for awd vehicle

Hi. I have Subaru Forester with 17 wheels. I want to get a full size spare. Is it ok to get 16inch wheel/tire set with matching diameter (within 0.1 of inch)? I need to be able to finish 200mile trip and is there anything I should be worried about having mismatched wheel? (At least according to tirerack, the 16inch tire I am looking at will be within 0.1 inch in diameter of OEM tires and less than 5revolutions/mile difference)

I am told 16 inch wheel will clear the brake. Has anyone tried similar setup?

17" may be needed for clearance, why not get 17" ?

You should not drive more than 10-20 miles on ANY spare with a AWD Subaru. Also go slower speeds.

The item that counts is not diameter of wheel but the rolling circumference. Distance around tire that touches ground. It that is off by 1/4" vs three other tires according to Subaru too much. My mechanic states 1/2" is okay but beyond that will break the internals of transmission in his 20yrs experience with Subaru.

17" may be needed for clearance, why not get 17" ?

More than likely, a 17 will not fit in the spare tire well.
Actually, I would be surprised if a 16 fit in the well.

If the outside diameter of the tire differs by less then .1 inches, consider this: regular tire wear, using any spare not part of your rotation, weight loaded unevenly and slight differences in tire pressure could all make working diameter from one side to another or front to back greater then .1 inches. There should be no problem Driving as your car deals with these differences constantly regardless.

The biggest problem would be throwing on a summer spare to replace one snow tire.

For piece of mind, check with the dealer for fit. Regarless of who tells you anything about fit it means little if it doesn’t come from the factory or Subaru dealer service department, and that includes the spare tire well. Fit there is determined by tire width and tire diameter and not rim size.

if you’re buying a set of 4 rims and tires, you should be ok as long as it clears the caliper.
If you are buying 1 rim/tire to replace a bad tire, DON’T.