Old tires. Safe?

[69280sl]

I have had a new set of 205xx14 tires in my basement for about 35 years. In fact 3 of them are still in the mummy wrap. Because of the absence of sunlight, more or less constant temperature etc., I am tempted to use them on another car, not my Pagoda.
I would appreciate guidance and comments on the adviseability (safety) of doing so.

Thanks
Gus 1968 280sl

[Douglas]

Why would you do that, Gus? Are they unusual in some way? I can't comment on the chemical properties of rubber and how it breaks down, but I've got to think you're taking a huge, unnecessary risk driving on those. The only scenario I could personally see is putting them on a car that's trailered to car shows and not really driven.

[69280sl]

Nothing special about them Douglas. I am motivated solely by saving the cost of a new set, but only if safe to do so. Thanks for your probably good advice.

Gus
68 280sl

[scoot]

quote:Originally posted by 69280sl

Nothing special about them Douglas. I am motivated solely by saving the cost of a new set, but only if safe to do so. Thanks for your probably good advice.

Gus
68 280sl

Having them wrapped probably has reduced the damage to them, but I wouldn't use them on a car that is actually driven.  But given that your motivation is to save money, I think what you have in your basement is worth more than the cost of a set of new tires.  There is going to be someone out there who WANTS "new" tires that are actually 35 years old for their period show car that they want period (original) tires for.  Finding that buyer might be a challenge.  I would try two places:  eBay and Hemmings.  Someone who has a low-mileage car from the 70's might be highly motivated to say that they have "the original tires" on the car.

[Mike Hughes]

If anyone harbors doubts about the wisdom of considering replacing aged tires, one might want to take a look at this:

http://abcnews.go.com/Video/playerIndex?id=4826897

[Cees Klumper]

Very interesting Mike - it tells us that the last 3 or 4 digits of the manufacturing code on a tire give us its age, for example '118' means the tire was produced in the 11th week of 1998, and '3403' means it was produced in the 34th week of 2003. In other words, a 3-digit code means the tire is from the last century, and a 4-digit code means it is from 2000 onwards. Interesting to see that tires as old as 4, 6 or more years old are being sold at Sears, Walmart and other reputable stores as new, although in the UK, consumers are warned to replace tires that are 6 years or older. Also telling is that, on some tires, the manufacture date code is on the inside wall, not intended to be overly visible.
I reiterate my own experience here, that I lost a large piece of tread one of my Michelin tires on my Pagoda on the highway, a year after I bought the car with the tires looking like new. In the ABC News 20/20 documentary, losing a piece of tread is shown as being quite dangerous.

[Garry]

As an side story on old tyres, on my modern Mercedes ML and a C180 I used to own, I was only getting 40-45,000 Kilometers (25-28k miles) on the tyres until my local tyre dealer who I have dealt with for about 15 years told me that I should buy my tyres a year before I think I needed them and hold on to them in a dark cool spot in the garage to give the tyre time to properly cure and that I would see a marked improvement in milage.

I have done this with the current set of tyres (same brand)on the ML which I stored for 18 months and they are now at about 65% wear (3 years of use) but have have already done 85,000km and look like they will exceed 100,000k (60k miles) if I don't sell the car in the meanwhile.

Maybe it is an old wives tale but it has completely convinced me of the benefit of doing so.

[Raymond]

Garry,
So what you're saying is that letting a tire get hard and lose some of it's traction is preferable to spending for a set of tires.  I prefer all the grip I can get.  Hard rubber lasts longer but slides better than soft rubber.  The difference may not be noticeable until you discover that softer tires with better grip might have stopped you just enough inches shorter so that you would not have hit that car in front of you.

[Longtooth]

Variations in tire reliability as function of age (predominanly temperature over time) is by far more associated with the mfg'er and tire model than age or temperature, though aged at temperature and while driving or under load(over/under inflation etc), trends down in reliability for all tires.   Some tire brands and models have better reliabilty at 8 years of use than others do after 2 years in the same driving environment (Phoenix).  Tire life is significantly better in cooler climates than hotter ones.

From the DOT reported data to date, oxidation rates from the inside of the tire are the dominant mode of causing tread-loss... this is apparently because the inside tire coating and ply are the most susceptible to both temperature & mechanical stress (over-inflation, under-inflation mostly). 

Assumedly, Basement environment is both cool and dominanly UV light reduced..... therefore oxidation rates are reduced.  Stress on tire ply's while aging under no load is only the residual stress at mfg'ing, which reduces with age (stress relaxation).

If the 35 year old tires were a Micheline high quality model, personally I'd use them in a non-family used car and pay attention to inflation on a more frequent interval than I would otherwise, as well as not drive agressively on them, nor in extreme hot environments.

[Mike Hughes]

And might these oxidation rates on the inside of the tire be why some high end shops are now offering pure nitrogen tire inflation?

[Garry]

Garry,
So what you're saying is that letting a tire get hard and lose some of it's traction is preferable to spending for a set of tires.  I prefer all the grip I can get.  Hard rubber lasts longer but slides better than soft rubber.  The difference may not be noticeable until you discover that softer tires with better grip might have stopped you just enough inches shorter so that you would not have hit that car in front of you.

Hi Raymond,


I suspect but am no expert in the field, that all rubber continues to cure with time.  I think what the tire person was suggesting was that it was better to use a tire used after full cure of the rubber after vulcanization and that this could take as long as six months.  As stated, no expert in this area. Anyone in the forum know the relative curing rates for rubber?
On this assumption, a bigger part of the tire wear would be in the first few months of use if it was a 'hot off the press' tire. Then again the new sticky type tires are great for grip if you are prepared to pay the premium in wear rates. 

 

[dseretakis]

Don't drive on old tires.  I've have 3 tire blowouts on old tires.  Luckily I don't drive fast.  I recently replaced a like new set on my 220/8 because they were 15 years old.

[Longtooth]

And might these oxidation rates on the inside of the tire be why some high end shops are now offering pure nitrogen tire inflation?

Answer: Duh.  And you can guess when they started using nitrogen in more and more shops (answer: during the federal investigations on the relatively high rates of tire failures in Phoenix area).  It turns out that it's the internal tire oxidation rates that dominate.  Tire co's have been investigating new coatings to put inside the tire at mfg'ing to reduce the rate of oxidation as one alternative (from DOT reported info).   Bottom line is still the fundamental problem of overloading tires (which includes irunning them underinflated, both a form of over-loading from the perspective of stress, and faster rates of oxidation due to over-heating them)... then running thru a road hazard (big pot-hole for example)... which starts the process of internal delamination.   

I was recently at Costco to have a slow leak fixed (it was a nail at the intersection of side-wall with track... so I had to replace the tire)... and while waiting I was looking at the date codes on the tires in the shop.  I couldn't find one more than 4 months since mfg'ing, and most were 1-3 months .  BTW, Costco uses nitrogen.   

I have an unfounded belief that tire mfg'ers over time replaced treadwear issues with tire reliability issues.... improved treadlife was a visible and competetive driving force .... people bought the higher treadlife guarenteed tires.  Reliiability issues, unless extreme, are subtle and far less visible to the public or to standard independant tire testing, so it stands to reason that mfg'ers were not as incentivised to deal agressively with reliabilty on the new longer tread-life tires ---- and apparently got to the hairy edge (with Firestone going over the edge on a higher proportion of tires (they called it a "quality problem"... which means their quality requirements were already at the edge, meaning imo, they knew a higher proportion would fail... they just goofed in their estimates of the proportion of tires that would fail).  The Ford/Firestone fiasco brought it all to the surface.  Interestingly the DOT tests still aren't completed nor is there a final report that was supposed to be published by Jan '08.  I'll bet a dollar to a donut the final report is hung up with lobbying by the tire industry to prevent it's publication or to have the report modified to relieve it of too much burden in correcting the fundamental issues --- which are likely to cause tire prices to rise or tread-life to be reduced again.

You know why houses stand for 100 years or so... unless termites, hurricanes, tornados, earthquakes, floods, and fires doom them before their time.... it's because the building codes use engineering test information that adds a 2:1 factor of safety in all structural members.  This means that when the contractor cuts corners or uses less then the best practises the building is likely to still stand the test of time without falling apart in the next storm or light earthquake.... not to mention the variatioin in lumber and quality of concrete.  With a 2:1 safety factor a few termites more or less won't cause the floors to come apart and foundations to crumble to dust either.  Tire reliability standards are apparently not subject to as stringent a set of engineering rules and codes I guess.  Strange, in-as-much-as we spend a substantial part of our lives on the road.  I suppose the tire/auto industry lobby must have more clout than the building construction & materials lobby.