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Dry Rot in tires

I was told by the service advisor at our local Audi dealer that the two rear tires which had 38,000 miles on them were showing dry rot on the inner sidewalls and should be replaced immediately. Should I have bought this ? What is dry rot in tires that are used daily in a large modwestern city ? What cuases it? Are Pirelli tires particularly vulnerable ?

Cracking is a normal aging process of rubber. The rubber in tires is no exception. The cracks are caused by a combination of stress and oxidation - so it is both a mileage as well as a time phenomenon. Good tire maintenance will slow it down.

So the first question is did you do a good job of maintaining your tires? Inflation pressure checks every month? Rotation every 5K to 8K?

If not, then it’s hard to assess how much contribution is the tire and how much is just plain neglect.

Because many folks only think of tires in terms of miles, tire manufacturers and car manufacturers have been issuing bulletins saying that tires should be removed from service when they reach a certain age. There’s a bit of spread on the time, but it seems to boil down to heat. If you live in a hot state (AZ, CA, TX, NV, NM, and FL) 6 years is the limit for a properly maintained tire. In cold weather states (MN, WI, MI, ND, MT, etc.) then the limit is 10 years. States in between are … uh …in between.

I don’t know specifically if there is anything in Pirelli’s that make them conducive to such a problem, but it could be the tires were not exactly “new” when you bought them. Sometimes they sit on the shelf for a long time between date of manufacture and date of sale. And sometimes, even if it isn’t all that long, the conditions under which they are stored can affect their life. The date is in a code stamped on the tire along with all of the other info you’re accustomed to seeing, like the size and speed rating, etc. On the other hand, you could have just gotten a bad couple of tires.

  1. Look at the tire sidewalls near the rim and look for tiny cracks. This is normal for tires with some age but they do need replacing ASAP.


Norm, take your medicine and go to bed, nobody wants to hear from you.

Most tires are serviceable for 8-10 years. Some brands are more prone to deterioration than others…Pirelli is living on a reputation earned 30-40 years ago. My daughter just purchased a set one of which was defective, pulled hard to one side, dealer replaced them with Michelin’s at no cost and no argument…The Pirelli’s were made in Argentina…

But the question here is, can YOU see any sidewall cracks?? Tiny little “checkering” cracks do not count. Sunlight is what degrades tires. The outside should show cracks before the inside…If you don’t trust the service writer, (smart move) check them yourself! Pull one off and really look at it!

Tires do not dry rot. Dry rot is a fungus that attacks wood (and it requires moisture!)

you are correct but sometimes in language terms or phrases that are not exactly correct are used to illustrate an idea or to make a point and in this case the tire supposedly has some dry rot. Everybody uses this in normal conversation.

age, driving habits, and environmental conditions have a lot to do with it and dry rot is common no matter the brand of tire.
examine the sidewalls of the tires and down inside the tread grooves. if you see a lot of small cracks then you should consider replacing the tires.

belts and other rbber parts are also prone to dry rot (weather checking if you prefer).
this is often the cause of air ride problems on vehicles equipped with that option. the rubber bags develop weather checking where the rubber folds and the slow air leaks begin.
when you see a Lincoln or Lexus running around slammed to the ground you can assume the bags have given up.

“Dry Rot” in tyres is caused mostly by ozone and age. Mileage has little or nothing to do with it.

It is a real problem, but few tyres will ever have the problem. Most modern tyres have less of a problem than they did in the 60’s.

If your tyres are say 3 years old and have cracks in the sidewall it is an indication that they may have been in stock a long time before you got them or had been stored in a high ozone area.

How old are the tires?