consumer warning / doomsaying about tire shelf life [NAC]

[Huw Powell]

> Interesting piece all right.

In a really sensationalist kind of way, yes.

> I have read somewhere that the flexing of a
> tire in use keeps the oils in the rubber distributed throughout the rubber,
> but if a tire isn't used for a long time the oils separate, reducing the
> flexibility of the rubber. 

I have heard that, too.

I also have a set of four old pickup truck tires (bought used maybe 15 
years ago?), one of which ran on a truck for some plowing & such, very 
few miles, and then sat on the carcass for about four years undriven. 
It looks like hell compared to the other three, which stayed indoors. 
UV and temperature extremes take their toll, I guess.

> A couple things I noticed in the documentary - most of the vehicles in the
> "warehouse of death" were SUVs, pickups, or vans and the tires they showed
> with tread separations were light truck tires. 

I noticed that, too.

> A tire failure on a vehicle
> with a high centre of gravity is inherently more dangerous. A large SUV
> gives the illusion of safety, but I have seen data showing the fatality rate
> for SUVs is higher than for cars due to the higher frequency of rollover.

Yes, as I watched the video I thought, "what's up with those dangerously 
designed vehicles?"  I hit a tire on a rim once in my 90Q doing about 65 
mph, broke the strut housing, wheel ended up with about 30 degrees of 
camber.  Car handled fine, pulled over expecting to see a flat tire.

> The shot of the highway tread debris was misleading - that was a transport
> tire tread and most transports run on re-treaded tires, which have a high
> frequency of tread separation.

I noticed that, too.  Tractor tires get re-treaded twice (they melt 
little marks in the side to keep track), and they can't run retreads on 
the front axle. (USA-specific)  Learned some of this talking a to guy 
whose waste transport trailer blew a tire (sounded like a dynamite blast 
in the nearby gravel pit!).  Tire was completely shredded, but he had no 
trouble pulling over and parking to await service help.  Of course, it 
helps that there was a second tire on the hub.

> Another reason for tread separation is under-inflation of a tire; the heat
> build-up can cause the tread to fail. How many people routinely check tire
> pressure? I see a lot of vehicles driving around with at least one soft
> tire.

Oh, there you go with that whole "tire inflation" thing again.  Why do 
people keep dragging partisan politics onto the list! ;)

One other thing I noticed - the industry spokesman representing those 
who would make the most money off this (after absorbing losses of old 
tires in inventory?) said it was not an issue.

My final take: I think it's a load of BS.  Without the sad sob story 
lead, most of the drama would have been deflated...

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/