different sized tires on the rear?, had to abandon the 914 at my inlaws tthis evening. :( Options

[VaccaRabite]

As I continue to fine tune the car getting ready for the 3 hour drive out tot he ECC, I drove it out to my inlaws Thursday night. Spent Friday crabbing, and then was able to spend all day today tuning. Took several test drives that went perfect.

After washing the car, I noticed that one of the tires (drivers rear) had a 4 inch crack in the sidewall. Less then 2000 miles on these tires too. Dammit!

Anyway I changed the tire with my spare. The spare is a larger tire then the rest of the tires, and I was worried that this might cause me a problem. I think that it did.

When I went to go drive out, I started slowly. Rolling in first I heard the car go: "clunka - clunka - clunka" and I stopped. Backed it right back into my parking spot in my father in law's driveway. My wife was there and I got a ride home with her.

So, my question. What made the sound? Was it:

1. the rear tires were mismatched, I was hearing the differential eating itself?
2. The spare tire was not centered on the hub properly?
3. Some other issue I have not yet thought of?

My guess is number 1, which is why I left the car after rolling it forward about 10 or 20 feet and hearing it not sound happy.

I guess, if I had been smart, I would have taken off one of the front tires and put that on the rear so that both drive wheels were the same and the fronts were miss-matched. We did think of trying that before I left it, but I was exhausted and so was my son, so we just left it until I can get back there with a new tire sometime next week.

The tires are mismatched because the full size spare is in the stock size, but my street tires are smaller diameter.

I don't think I did any lasting harm. As I said, it only went a car's length before I stopped it and backed it back into the parking spot.

Thanks
Zach