Differenting tire sizes

Shorter?
Yes, the width is shorter by 10 mm.

It’s both shorter and narrower. It’s 10 mm narrower, and it’s about 7 mm (70% X 10 mm) shorter from bead to tread, or 14 mm shorter overall. With that type of size description the first number is the tread width (215 or 205), the second number is the ‘aspect ratio’ the ratio of height/width, here 70 (%). So if height/width = 0.7, then height = 0.7 X width.

Since the traditional “donut” that many cars have is very small in comparsion to normal tires, do they pose a similar or worse ware on a car if driven to long?

Yes, they’re for short-term use only.

I want to thank everyone for the info, it was bothering me a bit given this was new to me and the AAA guy really didn’t help.

Here is one more little tidbit. Chances are that your spare still has full tread depth. Tread depth on a new tire will be somewhere between 10/32" to 12/32" deep. That is about 8 to 9.5 mm. Tires are considered worn out at 2/32" or 1.5 mm. That means that there is 6.5 to 8 mm of useable tread wear. Since the radius of your spare is 7 mm smaller, its about the same as a worn 215 70 r 15 tire. That is within the tolerance of your differential. Its possible that a 215 won’t fit in the spare tire well. It also might be the specified tire for the base model of your vehicle.

“…Since the traditional “donut” that many cars have is very small in comparsion to normal tires, do they pose a similar or worse wear on a car if driven too long? …”

Donut spares are supposed to be used only temporarily - as in 50 miles at 50 mph. They are built to mininal standards - only enough to satisfy the 50/50 rule.

And I agrre that it sounds like the place that sold you the vehicle just slapped something on there - which brings up the issue of tire age.

You need to check how old your tires are. Here’s how:

http://www.barrystiretech.com/dotcoding.html

UPDATE…

I was unable over the weekend to get the flaten tired fixed, so still drove into work this morning with the regular but small tire still on. TWO major things occured on the drive in and not sure if the tire was the cause to 1.

Issue 1: While driving in the front tire fell off. Yep all 5 lug nuts came off and the tire came off kinda. Not all the way. I was driving slow any way and started to hear what sounded like the tire going flat. I pulled over to find all the lugnuts on the ground and the tire about to fall off. I called a tow truck we took it to a local shop who replaced the lug nuts and the 5 things your screw the lugs nuts onto. they said they saw no other damage. Also said the different size tire would not have caused that, but the lack of tightness is why the lug nuts came lose. They said I was lucky and didn’t get killed or do more damage. I believe them when they said no other damag was done because they could have said this and that needed to be replaced and didn’t.

Issue 2. Before the tire came off my CEL came on and the car engine isn’t sounding right, kinda struggling when at idle and I wondered if with the smaller sized tire could have caused something in the timing maybe? I have not had a chance to check the CEL for code yet.