I got an internet combo-deal to change oil and rotate tires at a shop in Sunnyvale, CA.
However, now mechanic called me back and is telling me that I have to change all four tires due to the wear. And that they won't rotate my old tires unless I get new ones for $435.
The tires aren't actually in that bad shape and tire protector is still clearly visible (I did not measure the depth though). Last tire change was a little more than 14K miles ago.
Is there a legal or technical reason why they can't rotate my old tires? If there is a reason, then what is the condition to consider tires too bad to be rotated?
It turns out my old tires have 40K mile warranty. I asked the tire shop how come they have become worn off so soon. They said that a tire inner edge has cracked for one of the tires. This raises question why they did not offer to change only two tires if only one tire is bad.