<VV>Tire "aging"

[Bill Elliott]

Tires absolutely age... in several ways.

The tread compounds significantly harden with age, leading to 
dramatically reduced traction. A 5-6 year old high performance tire 
often degrades to the same traction levels as a newish economy tire... 
and economy tires get even harder. Of course, how bad and how quickly 
they degrade depend a lot on the tire itself and the levels of sun and 
oxygen it's exposed to. I try not to drive aggressively on tires that 
are over 5 years old.

Collector cars are particularly prone to this issue since the years and 
not the wear do the most damage.

The rest of the tire ages as well... just not as quickly. Sun and oxygen 
are still detractors (why you see RV's with protectors over the tires 
all the time when parked) and the failure mode can be pretty 
spectacular. (Dad recently lost a trailer tire on his camper... it just 
flew apart at speed.. damaging the trailer as well). I concur that 10 
years is a good rule of thumb... less if the tires have ever been run low.

The advances in tires and tread over the last several years have 
resulted in tires that still have tread and look good long after they 
are unsafe. I actually think this is a big part of the Ford 
Explorer/Firestone issue... with tires that last 75k+, many of these 
tires were over 5 years old... many of those years likely run at low 
pressures, overheating the tires repeatedly. With tires that only last 
20k, this isn't nearly the same problem...

The old Lotus Esprit I picked up had brand new Pirelli P7's on it.. 
still had the molding nubs. Looked absolutely perfect... always garaged. 
But they were put on it 1991! They were square from sitting and running 
even 30mph was disconcerting. They were sold hard we cracked a rim 
dismounting them... and resorted to taking the 3 piece rims apart to 
dismount the other tires...

Tires should be stored in cool places out of the sun and wrapped in 
plastic...

Bill

>
>
>> According to all the experts I have canvassed, tires do age to the 
>> point of
>> being dangerous. I had brand new (less than 1000 miles) Michelin 
>> tires on my
>> RV, but they were 15years old. The rig had always been garaged, so 
>> there was
>> no weather checking. I didn't want to have to cough up $800 for 6 new 
>> tires
>> if I didn't have to.
>> The consensus was that anything over 10 years old is suspect for use 
>> on an
>> RV. This might be a good reference point for deciding what the "aged" 
>> life
>> is for car tires. I'm now $800 poorer.
>> Andy Clark
>> 1966 140/4 Monza Sedan
>> 1966 140/4 Yenko Clone
>> 1966 180/4 Cord 8/10 #60
>>  
>>
>
>


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