Tires: How long is tire life with car stored?, dodge challenger, nd mt

Question
QUESTION: Hello,
I have a collector vehicle (Dodge Challenger) stored in my garage. I drive it around the block a few times a year and try to keep the fluids changed every year or two.
I am wondering how long the life of the tires will be under this situation? I have heard they have a "shelf life" even though they are not regularly used.
Is there any way I can tell from looking at the tread or sidewalls if there is a problem with aging?

Also, any recommendations on air pressure for a car that is stored (eg. more air or less air than normally recommended for driven vehicles?)

Thank you very much!!

ANSWER: Brad,

There are a number of problems.

First is that tires will flat spot if left loaded and in contact with the road surface for a long time.  Over inflating the tires while in storage helps, but I wouldn't exceed the maximum value printed on the sidewall - and of course, lower the pressure back down to operating levels.  What pressure to over inflate to would depend on what the operating pressure is sipposed to be - and I wouldn't use any more than 5 psi.

But there exists the problem with tire aging. The problem here is that stressing the tire reveals the rubber's condition - so a tire in storage doesn't show the condition as readily.

I would use the manufacturers' recommendations - if you live in a hot climate (AZ, CA, NM, TX, and FL) then 6 year limits and if you live in a cold climate (MN, ND, MT, WI, etc)  then 10 years - and states in between are .....ah...... in between.

---------- FOLLOW-UP ----------

QUESTION: Hi,
Thank you VERY much for your detailed reply. It was very helpful!

One follow up question - How can I tell if a tire has a flat spot in it from storage? Will it be obvious to see or is it something that is not noticeable?

Also, I've sometimes heard of people putting cars that are kept in storage for awhile on jack stands. Is this advisable to save the tires?

Thanks again!

Answer
Brad,

The recommendation to put a a car on jack stands comes from trying to prevent the formation of a flat spot.

You can tell you have a flat spot if during the first few minutes of driving there is a vibration that gradually diminishes over time.  The problem here is that a "permanent" flat spot may be formed during that time and you will never get rid of the vibration.