1998 Dodge Caravan Tire mismatch

[Jerry32]

I bought a couple of used tires yesterday as my car is way out of align and unfortunately have no $$ to buy new tires.
My son had an accident several months ago, not major damage but front tires were really bad. We are planning on selling the car within 3-4 months so thought Id look for some used tires. My car uses P20575R14 tires & they were hard to find, & finally found 2 at separate locations. They have lots of tread & I was happy to discover that they were both Michelin tires. Unfortunately when I got home I took a closer look and discovered one was P21575R14 and am just wondering if that is a safety issue or problem. I could not tell when driving--they felt fine. I realize a mismatched pair is not the best scenario but would like to keep them if compatible as cannot find any others right now. Any input would be much appreciated..
..BTW way the name on the '215' tire is Michelin Plus 80, the other tire 20575R14 is Symmetry..thanks so much..

[fredjacksonsan]

According to the tire calculator here, there's only a little over 2% difference in speed of rotation, so shouldn't hurt anything.

Keep in mind though that if you have both these tires on the drive axles, one side will always be turning faster, so your differential will be turning more than if they were the same size.

If it were me I'd return to where you got them and see if they can't match it up for you.

[fredjacksonsan]

According to the tire calculator here, there's only a little over 2% difference in speed of rotation, so shouldn't hurt anything.

Keep in mind though that if you have both these tires on the drive axles, one side will always be turning faster, so your differential will be turning more than if they were the same size.

If it were me I'd return to where you got them and see if they can't match it up for you.

[fredjacksonsan]

According to the tire size calculator at 1010tires.com, it's only about 2% difference in rotation speed. That's not too bad, and might not cause any issue at all.

However if you have both tires on the drive wheels, one side will turn faster than the other, and that could cause an issue with the traction control or ABS, depending on parameters. If you don't have either, then the only thing that will happen is the differential part of the transaxle will be turning more than it would if the tires were the same size.

It's just me, but I'd go back to the tire dealer and ask if they could match up the size, just to be sure.

[Jerry32]

Thanks for that info & those cool links!
The tires are both on the front and seem to be smooth driving.
I called the place that put the wrong one on & he said he'd have another in this Monday & would replace. Am not sure if that's true as he said he had the correct one in stock when I called & when I got there, so we'll see what happens. I only paid $30.00 including mounting so I guess I got what I paid for and happy to have any tread instead of bald tires so I guess I need to be more cautious. Thanks again--