if its beyond fixing then yes it is true you should replace all 4 tires. That being said, I still dont think "tire insurance" is a good investment.

 

Yeah you have to replace all four. If one tire is larger (the new tire will be slightly larger) it will want to spin slower than the others. This will cause the diffs to heat up. There's a spec for how different the diameters of the tires can be, buts it's not much at all. Your better off replacing all four tires and saving your drive line.

 

+1

unless your remaining three tires are fairly new you gotta do all 4... the con of a awd

 

It depends. If there is more than (IIRC) 2/10 of an inch difference, you'd have to replace all four. So if the tires are relatively new then you'd be fine with replacing just one. Also I believe some shops can "shave" tires. So theoretically at least if you needed to you could shave the one new tire down to match the others. Tire insurance is probably easier and it's relatively cheap. FWIW I have been driving for 18 years and never had a tire that couldn't be repaired with a patch. Just lucky I guess, but the odds of blowing a tire are relatively low.

 

Just a correction, its not 2/10th... its 2/32

 

I have had to do the same thing. i had 2 flats in one week and replaced just the 2 tires instead of 4. i did this because i only had 4k miles on that car. Wouldn't it make a difference as to how many miles have been driven on those tires to determine whether you need 4 new ones or just 1?

 

Same here. I just blew out two on a potlhole. They only had about 4,000 miles on the set but I never realized how worn the old ones were until I got the new ones today. Now the hard part is explaining to the township, who's reimbusring me for all this, how I had to replace all of them...

 

Or you can have the one new tire shaved down to equal the rest.
Or you can buy 4 new and sell the other 3 and get some of your money back.

In regards to the insurance.. IF they put it in writing that they will replace ALL 4 because one can't be fixed, yes, I'd pay for that. But I would not do it unless that it put in writing.