Flat.

[Voleurz]

I thought I would share my story now. About a week ago I was driving to a summer camp that I work at to help close down for the winter. Anyone from BC can tell you how hard the Cariboo is on vehicles. Its about a 30 minute drive off the pavement down a dirt road. I was doing about 70km/h (a little fast considering it was dark, about 10 at night)

Every winter the frost pushes more and more large rocks through the surface of the road. I came fast around a corner and I saw it. A big, round, fat stone pushing through the surface of the road. It was too late to swerve. My front left tire took the hit VERY hard. Within seconds the TPMS light came on. I pulled over and took a look. The air was rushing out of the tire so fast it was stirring up dust. Lucky I knew how to change a tire. I changed it to the donut spare and continued on my way. The next day, I limped into town. I was concerned if the spare would hold up but I made it. I dropped into Kal Tire to see if they could fix it. He said whatver I hit, I must have hit it hard, the impact split the bead on the tire, it was unfixable. The Kal Tire guy said they only tire they had that would fit my care was a used snow tire that is a bit bigger than the others. Im still running it now a week later.

Is this going to cause any damage to my car? They rotated it so that the oddball tire is at the back, and I plan on getting a new one very soon. Is it dangerous to be runnning a tire thats visibly bigger than the others?

[Captainmorbid]

If it was a steering tire it might be a bit dangerous, but on the back end it'll just wear the tire out at an accelerated rate. And it might be a little tougher on the suspension and braking components. I would change it asap. I assume you have a full set of winters on the way? You'll need them, the stock tires are definitely not good enough for your snowbanks...

[RichBinAZ]

I have heard that running with an odd sized tire stresses the tire opposite. Usually this is with the donut spare, but in your case, the snow tire will run with a bit more load on the inside corner and the opposite tire on the outside corner.

I haven't looked at the donut spare yet but assume it is smaller than a regular tire, if so, then the ABS should be able to cope with the different tire size. Otherwise the computer may think that wheel is starting to lock and drop the braking effort to that wheel, so putting it on the back is good and the load is slightly less back there.

One check you can do is to put your hand on the tire after a run to see how hot it is getting. Not an exact science, but a guide.

Hmmm, I wonder if that is why donut spares are rounded... to avoid corner loads???

[Iceracer]

Running it on the back won't cause a problem. Might make the handling a little wonky.
Running odd size tires on the front could eventually damage the differential.

[missourimule]

Same thing happened to me. We don't know what happened but it ruined the tire of only 1,800 miles. We limped into Texarkana to the local Ford dealer but they didn't have the tire in stock nor was there one anywhere to be found. We had to put a Hankook tire of the same size to proceed on. When we arrived in Hot Springs, they didn't have the tire either. It is a KH-25 Kumho and apparently somewhat rare although I don't know why.

I feel like you do regarding driving on those small spares. This was the first and only time I have had this happen and I have driven well over a million miles in my life. The tires can be found on ebay and other sites for about $50 or so. You might want to find an original and replace the other tire and keep a full size tire in the trunk area (I have the sedan) in the event this ever happens again. And when you get to a garage have them put on the right tire so all four are matched.

We don't know what happened actually. It was a loud "bang" , drove a few hundred feet and the TPMS light came on. The tire had a large hole in the tread area. It was not a blow-out. The same thing happened to my neighbor in his Chevrolet pick-up yesterday and apparently was some debris on the road. I never saw anything, nor did he. With all of the trash being hauled around in trucks and stuff today it is a wonder it doesn't happen more often. Just avoid the "gaters" and other debris if you can see it in time. It is pathetic that these things find their way on the road. The offenders ought to be ticketed for spreading this trash everywhere.

BTW, don't run uneven tire sizes on the driving axles. The differential will be prematurely worn. Then you are looking at mega-bucks.

[aspitaletto]

Originally Posted by missourimule

BTW, don't run uneven tire sizes on the driving axles. The differential will be prematurely worn. Then you are looking at mega-bucks.

x2 !

[FORDSVTPARTS]

Running an odd sized wheel on the dack for a short time shouldn't hurt anything at all but I would get the correct tire on there sooner rather than later.