also look for cracking between the rows of tread, if cracked , replace

 

I had these, get rid of them as soon as you can. Keep your speeds normal until you replace them.

 

Definitely check the tread area, tires seem to dry rot there faster due to all the substances that the tires roll thru. I work for a independent tire dealer and we have a local stealership that sells tire for $15 over cost, they get the vehicle in the shop and sell other parts that are not always needed. Like all 4 struts on a 2 yr old vehicle. then turns parts in to warranty. Double Dip.

 

Many people don't know that there are many different things to look for with tires. Most just think, well, it's got 6mm of tread, so it's fine! I ran into this quite a bit helping friends work on their cars when I lived in Japan. People only drive a few thousand miles a year so they don't use much tread, but those tires might be 10 years old. Sidewalls cracking was something I saw all the time, but as was mentioned above, the cracking between the tread blocks is just as bad.


Jack the car up and look at the tires very closely, between the tread blocks especially. It's true the dealer might be trying to "fleece" you, but it's also possible they saw that "well-dressed middle aged lady" and are trying to save her the trouble/danger of a tire blowout.

 

http://www.tirerack.com/tires/tirete....jsp?techid=11 <--- How to identify the age of your tire.

After you have determined the age of your tire, there are some other things to consider.

1. Have you ever noticed that tires as they age start to howl? That is from the hard spots on them and the bumps, bubbles and uneven wear. Run your bare hand all around the tire tread and you can literally feel this phenomenon (wearing surgical/mechanics gloves makes this a cleaner experience).

2. While the picture you posted of the tire looks good, what is the TWI reading? If less than 2/32nds, then its time for new tires. If its 3-5 32nds, then your already there, might consider replacing them after 5 years.

3. Tire tread depth is more than just traction on dry roads; tire tread is what diverts water. Low tread will increase hydroplane.

Now I agree with most posters that sometimes you are being taken for a ride, but typically this happens to uninformed consumers. Check it out for yourself and learn how to "read" your own tires. You know how to fill up your own tank when the needle is on E? You know how to check your oil? Fill your Wiper Fluid? Inspect your own lights? Well all that and tire reading go hand in hand. In driver's ED we were taught these skills... maybe its time for a refresher.

 

And sometimes you can't even see dry rot. I had a tire with a slow leak that I couldn't locate. Took it to a tire dealer to break down and reseal the bead like I've often had done with the little spare donuts. The dealer said he wouldn't put it back on the truck and took me back to show me why. The inside of the tire opposite the tread was totally spider-webbed with cracks through to the cords so no wonder it wouldn't hold air long. Externally there was n evidence of dry rot.

 

Tire rot can definitely hide in the threads and bead, and five years in Arizona sunshine,(not just the heat), along with the chemicals car washes apply to make tires shine, leeches all the oils out of tires leaving them hard and ready to blow. While 30k miles doesn't seem like a lot, it would if the car is parked outside the majority of the day and in sunlight.