Aftermarket Tires And The Spare

The stock tire/wheels sold here on the CX 5 are 225/65 R17 and on the Signature225/55 R19. I would like to use the Michelin Lattitude Cross on the Mazda 17 inch wheel but the only size available is 255/65 R17. That's about 1.6 inches taller than stock. Would there be drive train damage if I had to run the car with the stock spare to a tire change place?

Does the Gen2 CX-5 come with a full size spare? Assuming that it does, I think that the difference in diameter between 225/65/17 and 255/65/17 is something like 5%. Over on the Lexus forums, people were running staggered wheels on their AWD cars, and the commonly known rule there was that there should never be more than a 3% difference in wheel diameter between any other wheel on the car. Anything more than this would damage the AWD system over time.

That said, I believe most spare tires are smaller in width and diameter than the full size tires that come with the car. As long as the spare is only used for the drive to the tire shop, and you don't go faster than 50mph (80kph) with the spare on, there should be no issue. Also make sure to never drive with a spare on one of the front tires. Move one of the rear tires to the front and put the spare on the rear if you have to.

Thank you very much. I'm not sure if it does or not. I guess the smaller spare on front would create steering danger plus as I understand it the AWD is front biased.

Pitter said:

Thank you very much. I'm not sure if it does or not. I guess the smaller spare on front would create steering danger plus as I understand it the AWD is front biased.

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Yes I think it is mainly due to the reduced handling.

Most owners forgot to keep their spare tire properly inflated.
One time, I needed to use the spare on my old CX9 (1st time after 6 yrs).
I found it to have only 30-40psi (should be 60psi).
I had to use it for 1mile distance to get home first.
The AWD felt strange. I drove very slowly with blinkers on all the way.
Once it is properly inflated to 60psi, the strange feel went away.
So, uneven height of rear tires might do damage to your AWD system after a long drive.

Good info, thanks.