I was thinking of getting a space saver spare from the junkyard off of v70. It is a 15" spare and is only $12.00
I am running 16" tires and I have AWD.
Can I use a 15" space saver in an emergency?
If so how long can I run like this?
Makes sense to me as it will provide a bit more room and be lighter.
Txs

 

I would NOT do it if I were you. The main reason most of the AWD systems in the early P80 cars go bad, is from uneven tire wear. It's best to make sure you keep evenly worn tires on the car at all times. Running a doughnut tire may damage the system in short order. Find a full size spare and always try to run evenly worn tires.

 

Thanks. I guess its a bad idea and I will drop it. It has me thinking though. I have a 16" spare, but in the winter, my snows are 15". I am at risk for AWD damage if I get a flat for the same reasoning.

 

Just don't drive around for hundreds of miles with a miss matched spare.

 

It's critical on an AWD to have tires that are matched in diameter. That's why it's so important to rotate them so they wear evenly as even having one tire worn more then the others can cause a problem or failure of the drive system components. In a fleet car we would replace all four tires with new if one tire had a problem and couldn't be repaired rather than put one new one on. Expensive, yes but that's the way life is in the AWD world.
I'd try to get a full size spare and even try to find a matching brand tire to the other four. It's so much cheaper than repairing your AWD.

 

Thanks everyone. Good thing I posted before going ahead with this space saver idea. I'll research tire rotation and frequency. I have not paid much attention to that with other cars.
TXS

 

With a mechanical AWD system like yours has, having all tires be the same size is critical. On newer cars with electronic AWD, it isn't as big of a deal.

 

Here are the problems with what's been said in this thread:
1. The rolling diameter of the tire is the only quantity that matters to the drivetrain, and nobody has mentioned that at all. The diameter of the steel rim is irrelevant. This shows, I think, that we're not thinking. Just my opinion.
2. Space savers don't last very long.
3. The idea that mismatched tires would destroy an AWD system has been presented without any evidence or even a theoretical basis. This is tantamount to insisting that you have to drive in a straight line all the time. This is because, as we all know, that the 4 wheels on a car all roll distinct different distances through every turn.

I try never to discuss differential operation on the internet, and I'm certainly not going to start now.

 

1. True, of course. He could get a smaller wheel and make up for it with a huge sidewall. I was assuming that was not an option he wanted to consider.

2. True. But they aren't supposed to.

3. The mechanical AWD system that this car uses can, of course, compensate for some variation in wheel speed (as happens on turns). But long periods of time with a great difference in tire size (overall rolling diameter), it cannot deal with and it will damage the system. There is a bulletin about it from Volvo. But since you clearly don't want to discuss it, I won't waste my time.

 

Thanks for you input ES6T. We appreciate your technical experience.

@ Fire Bird Parts: I don't find anything wrong with this thread other than the comments you made to devalue others comments.
1 & 2: I seriously doubt the original OP was considering installing 1 space saving, obviously smaller wheel/tire, and trying to drive it 6,000 miles until he got tired of it, then getting it replaced.
3. I wasn't trying to go into a 30 minute, 5,000 word essay to explain the function of the system and the gradual consequences of the poorly designed earlier Volvo AWD system. If the OP would have wanted the detailed explanation, I'm sure he would have asked for it.

Thanks for the brief post. If you have something to add, we welcome that. As for devaluing others comments, ain't nobody got time for that.