Join Date: Jun 2006
Location: Eastern ON Canada
Car: 07 OBW 2.5i D-4AT
Feedback Score: 5 reviews
I believe that's a "donut"type of spare tire. They are typically smaller in overall size and circumference than the stock wheels and tires.
Check your Owner’s Manual. It should list the size of the spare for your car. If it is the same as the one you have, and the other tires are also the size specified in the manual, then, if you follow the Manual’s instructions when using the spare -- especially limiting the driving speed and distance – there shouldn’t be a problem.
Your concern, however, is well founded. If one of the four wheels is an odd size, the front and rear drive shafts will turn at different speeds. This could put extra strain and wear on the transfer clutch (automatic transmission) or viscose limited slip center differential (manual transmission). But both systems are designed to accommodate some difference over a short term, otherwise turning a corner would be a problem. Consequently when using the spare, speed should be kept low, and the overall distance should be limited.
Some have bought a full size spare to avoid the risk, although, if the spare is not included in the regular rotation of the wheels (5-way rotation) then wear of the four working tires will eventually leave the spare somewhat larger than the others, and the same concern arises (although the difference might not be as great). From what I've read here, I believe the spare tire well in the 05+ models is barely large enough, if that, to hold a full size tire and wheel at the proper inflation.