Tires: Dry Rot, proper inflation pressure, snow traction

Question
My Volvo tires are getting to be at least 6 years old. Dont drive the car that much so there is still plenty of tread left but sidewalls are splitting.  I believe this is called dry rot.  I will be replacing the tires soon but I am wondering just how serious this problem can be.  I would appreciate your input.  Thanks so much for helping on this web site.
Tom

Answer
Tom,


This might be a very serious problem if the cords are exposed.  In essence the thing that is holding the tire together (the rubber) is splitting apart.  Like all organic materials, rubber deteriorates with time.  Once the cracks reach the cords, which are what provides the strength to resist the inflation pressure expansion, then the cords themselves will start to detriorate (They're organic, too!)

So if the cords are exposed, get this handled ASAP and drive slowly until it is handled.

If the cords are not exposed, then you have some time.

6 years?  Just about right!  It is my opinion that tires should be replaced every 6 years regardless of how worn they are in the following states - AZ, CA, NV, NM, TX, FL.  

I also think that tires should be replaced every 10 years regardless of which state you are in.  So if you live in a state that is cold, like MN, then 10 years is the number, but a state like NC, is probably 7 or 8 years.

Oh and these cracks can be aggravated by underinflation.

Look for the placard on your vehicle.  

The placard, among many things, tells the
original tire size and the proper inflation
pressure for that tire size.  The placard is
usually located on a doorpost or in the glove
box.

I like to use 3 to 5 psi above the placard.  I get better fuel economy, better tire wear, better wet traction, better snow traction, better steering response, better tire durability, and only give up a bit of ride harshness.

"They" say you should check your tire pressures once a month.  (In case you didn't know, tires leak very slowly.)  Don't trust the guys at the shop to check your inflation.  These guys are paid by the hour and this is one of the easiest things to shortcut.  Besides, there are a lot of mechanics you don't know where to look for the proper inflation.  No, it is not on the sidewall.

Buy yourself a tire gauge - a $5.00 pencil gauge works just fine, but I prefer the pistol grip digitals because they are remarkably accurate.  The check takes all of 5 minutes and it is the cheapest safety check you can make.  

Hope this helps.