Are Your Tires Too Old to Be Safe?

Even if they don’t wear out from use, our tires are aging out due to the simple fact that the components used in their manufacture doesn’t last forever.

We once compared a brand-new set of Vredestein Sprint Classic tires against a set of never-used Michelin X tires–the catch, of course, being that the Michelins had spent 32 years in dry storage. Our testing, done on a Triumph TR6, included both an emergency lane change maneuver as well as braking from 60 mph.

The Vredestein tires felt neutral during the emergency lane change maneuver while delivering safe, confident stops. The old tires? They were downright scary: snap oversteer when asked to change lanes while requiring 20 extra feet to stop from 60 mph. That can easily be the difference between life and death.

How old is too old for a tire? Our friends at Tire Rack offer this advice:

Our experience has been that when properly stored and cared for, most street tires have a useful life in service of between six to ten years. And while part of that time is spent as the tire travels from the manufacturing plant to the manufacturer's distribution center, to the retailer and to you,the remainder is the time it spends on your vehicle.”

So, a follow-up question: How old are the tires on your classic?

Tire Rack again offers this handy advice:

Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number with the 2 digits being used to identify the week immediately preceding the two digits used to identify the year.”

In their example, a tire marked with DOT U2LL LMLR 5107 was built during the 51st week of 2007.

If your tires were built before 2000, then Tire Rack offers this information:

The Tire Identification Number for tires produced prior to 2000 was based on the assumption that tires would not be in service for ten years. While they were required to provide the same information as today's tires, the week and year the tire was produced was contained in the last three digits. The 2 digits used to identify the week a tire was manufactured immediately preceded a single digit used to identify the year.”

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Comments
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David S. Wallens
David S. Wallens Editorial Director
2/28/20 2:15 p.m.

So, a PS to this topic: We just did some more old-tire testing using our 1984 Porsche 911 Carrera. The old tires have been tested, and the new ones installed. After we retest, we'll share the results.

Here's a sneak peek. 

bartjr1
bartjr1 New Reader
3/2/20 12:26 p.m.

The problem may even be worse than the article mentions - especially for cars that sit idle for long periods of time (think winter). During road use, centrifugal forces present in the tires helps keep the chemicals in  the tires distributed throughout the rubber. When sitting idle, those chemicals embedded in the outer surface evaporate naturally, while the internal rubber loses little. Very old tires began to crack on their outer surface which is of course a function of age, but tires that would otherwise have some life left based on their age, deteriorate much faster if they just sit. This is even further exacerbated when vehicles are left outside during dry, cold winter weather.

Other than a "trailer queen" used strictly for shows, there is no justification for keeping old rubber on a classic car. As an added bonus, when you refresh the tires with new, you gain the tremendous improvement in tire construction and technology. Small, lightweight sports cars from the mid-20th century do not even begin to challenge the capability of modern tires.

RadBarchetta
RadBarchetta New Reader
3/2/20 2:04 p.m.

If your tires don't have the modern date code, i.e. they were made before 2000, you need not bother asking if they are too old. The answer will always be yes.

David S. Wallens
David S. Wallens Editorial Director
3/2/20 4:33 p.m.

In reply to RadBarchetta :

Very much yes.

I'm new to Classic Motorsports, so this comment is to an article that is almost a year old.

First: you compared new 2020 tire technology to 32 year old late 1980s tire technology.  Seriously?!   I can only imagine what old-fashioned, behind-the-times tread design and tread rubber formulation the Michelin's had.  That was not a fair and reasonable evaluation to be sure.

Second: there are anti-aging tire and rubber chemicals on the market to preserve and protect rubber.  Age Master 1 Rubber Protective Agent, as an example, is such a protectant and approved under U.S. Military Specification: MIL-P-11520E.  It is a derivative of paraphenylenediamine [PPD6] that is an anti-ozanant/anti-aging chemical used in the production of tires and various other rubber materials and products.  B-t-w, I'm not associated with this product in any way, shape, manner or form, I just know about it and am an end user of it.

Third: Land fills won't usually allow tires to be dumped.  Why?  Tires, and most rubber products in general, don't degrad, and are a recycling nightmare.  States, Counties and Cities have illegal tire dumps or abandoned tire dumps and have no idea as to how to get rid of tires.  Tire manufacturers have for years looked into ways to recycle rubber that has already be vulcanized, vulcanization being a once only, one way, process.  A lot of venture capital business people have looked into tire pyrolisis, but that is very expensive.

The best way to store tires is to apply an anti-ozanant, tire/rubber protective coating, place the tire in a very large 55gal size, or larger if you can find one, trash bag, and store in a cool, dry area, away from electric motors and equipement [welders] that generate ozone.

I have a numbers matching, mostly all original, 1980 Corvette, including the original OE spare tire.  It has been coated with Age Master 1 Rubber Protective Agent a few times, I inspect it before every long trip and I would have no issue at all using it.  Matter of fact, every tire on every rubber tired vehicle I own, has been coated with Age Master 1 Rubber Protective Agent.  We completed a cross country trip in the '80 from our home in MD to OR via the northern tier states, 7,000 mile round trip, with 10 y/o Gdyrs and no issue.  When they wore out, finally, I replaced them with new, current  production BFGs.  And guess what?  The new technology BFGs performed better than the 10 y/o Gdyrs, no surprise there.

The interior materials of a tire are encapsulated in rubber.  The only way they would age/deteriorate is if tire aging cracks, any kind of cuts, or penetrating objects, went deep enough to expose those materials to air and mosture.  That is why a tire that has gone flat due to a tread penetrating object small enough for a repair, should be repaired from the inside AND the outside, to prevent, as much as possible, air and moisture from getting to the fabic carcass ply, which would absorb moisture and deteriorate, and to the steel belts, which would then rust/oxidation.

Just sayin'

 

 

 

 

 

wspohn
wspohn SuperDork
1/10/21 11:29 a.m.

Hmm - my 1971 Jensen Interceptor still has the spare tire it was sold new with - the wheel has never been taken out of the car. Bet that would be fun.

Drove one of my MGAs to the paint shop on 1970s Michelins - forgot about the old tires until I tried to corner normally.....

Of course new tires have minor foibles. Go out on brand new just mounted tires on a wet day - slippery as hell until whatever they coat them with at the factory gets scuffed off.

Tom1200
Tom1200 SuperDork
1/10/21 3:17 p.m.

My 62 Honda 90 has near original tires.......I'd never dream of using them beyond its pit bike duties.

 

Mike_8TY4SPD_MNL13GS_Vettes
Mike_8TY4SPD_MNL13GS_Vettes New Reader
1/11/21 9:04 a.m.

In reply to wspohn :

The tires are coated with a mold release agent, typically silicone.

 

wspohn
wspohn SuperDork
1/11/21 12:12 p.m.

In reply to Mike_8TY4SPD_MNL13GS_Vettes :

Other than just driving them to wear it off, is there ant way to wash it off before mounting the tires?

Mike_8TY4SPD_MNL13GS_Vettes
Mike_8TY4SPD_MNL13GS_Vettes New Reader
1/11/21 12:59 p.m.

In reply to wspohn :

Not really.  Tire manufacturers spray the molds with the mold release agent before the green tire is dropped in & cured.

I'm sure you've used a silicone based product, like armor all and/or others, and felt that slippery, almost greasy, feel to the surface afterwards, well that is what is on the tire.

At the temps & amt of time tires are cured at, the mold release agent is pretty much baked into the cured final product.

Might try a general detergent like dawn, or maybe simple green, not endorsing those products.  Most definitely not anything petroleum based!!!

Miles accumulation on the tires is the best way to 'wear' it off, and as you found out, not when it is raining for the first few miles.

 

pmac
pmac New Reader
1/11/21 11:22 p.m.

For those of you that are not able to drive your cars all year round I would like to suggest something that might surprise you. I have had more than one tire separate the belts in the tread. One I noticed when I saw daylight between the concrete floor and the bottom of the rear tire, second one I noticed when I was taking wheels off to clean on another car. After some discussions, turned out some others have had this happen as well. 

I now take off  my "road" tires and install a second set of "garage" tires when I put my cars to bed for the winter months. Might save your bacon when driving through the twisty parts!

 

PMac

marknoakes
marknoakes New Reader
4/4/21 12:58 p.m.

No contest on any of this material, but it would be helpful to be able to actually buy performance tires for the original wheel sizes. On one of my cars, I went from 13 inch to 15 inch wheels about 10 years ago and am now going to have to swap to either 16 or 17 inch wheels to get the performance tires I want. And then of course the profile isn't true to the original look of the car.

Torqued
Torqued New Reader
4/4/21 4:45 p.m.

A related matter I haven't seen in this discussion is heat cycling.  Probably not much of an issue for classic cars that are used mostly for shows or club outings, but it sure matters in autocross, at least for the high perforance sticky rubber treads madefor that purpose.  More heating - cooling cycles = less grip.

robertdhogan
robertdhogan None
4/4/21 6:18 p.m.

"the components used in their manufacture doesn’t last forever"

singular: doesn't

plural:  don't

the components used in their manufacture don’t last forever

TinBox
TinBox New Reader
4/4/21 8:46 p.m.

One helpful solution I've come to endorse is buying the gummiest tires available in your size, and enjoy them enthusiastically...then when you bin them at 6 or seven years, they're also worn out and have made you smile with every mile. Goes against most people's nature to replace 'perfectly good' tires that are never the less hard as hockey pucks, and dangerous in a panic situation. 

wspohn
wspohn SuperDork
4/6/21 11:09 a.m.

I agree with that - on my modern sports cars I always look for a wear index of around 300 or lower.

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