Aged Tires: a Driving Hazard?

It would be great if they had something like that. If you have a service mechanic that you trust, one that won't be influence by wanting to sell you new tires, He/she should be able to inspect the tire(s) if you're not comfortable doing it yourself. The best way is to pull it off of the rim to inspect it. However, you can get a pretty good idea without pulling it off of the rim. Let the air out of the tire by unscrewing the plunger inside of the valve, so that you can flex the side walls. If the side walls have dried out, they will be stiffer then a newer tire and hard to flex. Flexing the tire should emphasize any signs of cracking in the sidewall. If you are not familiar with how a good tire flexes and what it feels like, then you need to take it to someone who can tell. I would think that if you can flex the sidewall and it flexes back into shade easily and no fine signs cracking can be seen in the sidewalls, the rubber should still be lively enough for a few K more of driving. Again, this is a personal decision and I would never encourage anyone to drive on tires that weren't absolutely sure of. There are some things in life that aren't worth taking chances with, and I consider tires to be in that category.

 

There is a note in the Prius manual that says something to the effect that the Prius tires need to be inspected by a "quaified professional" (or words to that effect) after 5 years of use.