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MG MGB Technical - How old are my tyres? Too old?

I have some old used (by me!) Uniroyal 340 Rallye 185/70 tyres for my MGB, my question is how can I tell how old they are? Are they marked with a manufacturing date? I had some Michelin tyres replaced once and at a glance the fitter told me the year of manufacture, I would like to know how he did this.
Caravan tyres are said to only be good for 5 years before they should be replaced and I am wondering how long classic car tyres can be expected to last. The old Michelins were on my MGA were 25 years old and were so hard they squealed on cornering. I like the Uniroyals on my MGB a lot (terrific in the wet) but would not want to keep them past their "best before" date.
Can you help?
John.
John Prewer

A good question. Many people are tempted to use OEM tires for authenticity, while throwing safety (if the car is actually driven) out the window. My experience says that if the sidewalls exhibit any tendency to crack, it is time to retire.
Bob Muenchausen

So it's farewell to you then Bob.
.

Hey now, Use your own handle if you must post nonsense like that.
Or were you (the false .,. ) leaving and saying your farewells?
.

Dots and dashes aside,

John please make sure you are no where near me on the roads with your 25 year old tyres!!

I should use a swear word here to describe how irresponsible that is, after 25 years the rubber is going to be half the substance it once was when new!!!

I think you'll find the in the UK it is recommended that a tyre is changed every 2 years EVEN if it isnt at the lowest wear tread depth. This is espcially important if the tyres has stood attached to the vehicle in this time without moving and/or under inflated.

Every tyre offence in the uk will get you a level 4 offence qualification, which equals a flat fine of £2500 and compulsory driving licence endorsement of 3 points. So if you have a cut, lump bulge tear etc in two wheels thats £5000 and 3 to 6 points!!!!

I did note you said the michelins that were 25 yrs old WERE on your car, i do hope i read that correctly and you have removed them now.

If you think i'm over reacting the DETR do a leaflet on tyres, which you should get handed with every new purchase and if not places like kwik-fit will stock these leaflets.
Phil

There is a serial number in each tire (oops - tyre) that can be broken down into the year of manufacture . look in the web site of the manufacturer to see how to read it .

I see where these discount mail order tire places occasionally sell five year old tires ! .

Certainly any cracking is cause for replacement .

-Nate
Nate

All: beware of old tires (>5years) on your LBC. A fellow member of our local club with a beautiful award winning TR6 had old tires that looked OK to the naked eye. Had a blowout at 70MPH on I-55, hit the guardrail, spun, and hit it again with the rear of the car. He and his wife were lucky to come through with only bruises but the TR needed extensive work on both ends. On very close inspection the questionable state of his remaining tires became obvious. I would think about 5 years is the limit for good tires.
John: you are wise to try to determine how old your tires are-if in doubt REPLACE!

An interesting question is how good are silicone applications like Armorall at extending usefull tire life as I presume nearly invisible dry rot to be the ultimate culprit in old tire failure. Opinions?
Terry

John,
There is a DOT-code on the tire wall. For this year and week it should read something like this: 412.
Namely week number:41 and year:2. Sometimes the year is accompanied by a triangle which indicates decade ie nineties eighties and soforth. This is strictly from memory and it is obvious how to read the code once located.

Cheers
Erik
erik

Ive heard that armour all is actually bad for tyres.

A guy I talked to just dont use it on anything, he said it made dashboards etc crack.

Dont know whether theres any truth to it though
Paul

The following article explains DOT tire markings to include dating codes.
http://www.detnews.com/2000/commuting/0011/30/d12-154489.htm
FWIW, Clifton
Clifton Gordon

Paul, I have used Armor All since it first appeared in the early 70s, and my personal, tho not scientific, experience has been that it does not cause problems with rubber or plastic problems other than making some too slick in the hand for safe usage (like steering wheels and other items where a good grip is a measure of safety!)

One of the first things that sold me on its use was the simple fact that in Southern California's smog of the 70's (ozone and sulphuric acid laden air), it simply stopped any further rotting of any natural rubber items I had on a Datsun Roadster I had in those days. It didn't make the rubber better or nicer, tho it did shine it up. But it did do just what it said it would do - stop rot and protect rubber and plastics from UV, Ozone, and chemical exposure. It has done this for me in all the years ever since, and I continue to use it.

If your friend didn't like it, it maybe that he didn't like its slickness or perhaps his expectations were not in line with what it was intended to do. By this point in time, there may very well be several OTHER products on the market which do this job even better or have more exhaustive uses, but given ArmorAll's original intent, it at least seems to meet that goal empirically in the real world.
Bob Muenchausen

Interesting topic,
I recently purchased a GT that had been in storage (dry/heated & cooled) since 1984. The owner had purchased new tires but never really got around to driving it (REALLY! One tire still had the sticker info and all of them have a red & green line around the tire that you see on new tires).

So, the tires are old (18 years), but not worn (all 4 even still have those little nubby rubber things that look like wiskers or stubby hairs). Should these tires be replaced? They're Michellin 165 R14's (pretty close to original!) I'm not sure Michellin even sells 165 R14's anymore. They still had air, but about 20lbs (the owner moved about every 2 years and had the car shipped with him). Maybe this antique is worth something??? (just kidding).

What are your thoughts?
Steve F

There is another discussion going on right now as we speak (so to speak) on a local autocoss mailing list regarding the storage of racing tires. Racing tires with their "R" compound or similar rubber must not lose that super-stickiness. The general consensus seems to be to store tires on their side inside black garbage bags. The big enemies are light and air (hey, sounds just like beer!).
I would be concerned about very old tires even if they appeared fine; there is no telling what kind of cord separation is occurring where you can't see it. Seems to me many years ago tires were pretty crappy anyway, what with all the blowouts people used to experience. (Presumably, underinflated Firestones on Ford Explorers are the exception and not the rule these days).
Safety Inflated,
Dean
Dean Lake

Steve F

I know it sounds so ridiculous to throw away 'new' old tyres, especially when we're already accused of throwing things away in the present world today - however...

If a tyres has sat for 18 years on the same spot with out rotating, the weight of the car has compressed that tyre in the same position consistently. If a tyre is under inflated this is worse because now the sidewall becomes further affected too...

Tyres simply arent designed for that type of force in a constant axis and you can imagine a tyre company's view on this if you subsequently had a blow out. They could just tow the party line and say "our tyres do not have a stand time liff expectancy of this length in time!!"

Now if the tyres were left hanging up on the wheel, suspended on a pole through the hub section of the wheel, so no weight was on the rubber - how good would the rubber be then - it should be AOK, even after 18 - 25 years, the simple thing is though, i wouldnt be prepared to find out...! Get rid of the tyres and get something you know the history to....

The spare on my car was new when i bought the car, however i binned it. it was odd to the rest of the tyres and of dubious (to my mind anyway) make and i couldnt see me being happy with it on the car...

Its gotta be safety first, then safety FAST!! ;->
~PHIL

Phil

Last year a couple in thier cherry Morgan three wheeler had a blowout of an old but nice looking tire , about 20 minutes after I talked to them , flipped and killed them both .

Rubber's natural tendency is to degrade and loose the carbon black in it- that's why even new tires leave black crud on your hands .

I stored some new tires in garbage bags for under a year , they left black marks on the inside of the bags , I hope to run 'em bald before they get much older .

Armor All ? that's _crap_ ~ try not using it for a few months and see what happens - it destroys the natural polymers in your rubber/plastic and requires repeated applications or the item just disintegrates
I learned this the hard way after using it faithfully for several years then left the country and came back to discover everything rubber/plastic had curled up & cracked like old potato chips , this in a garage , no light nor heat . never again .

I now use Meguire's rubber / vinyl cleaner /
protectant for 10 years with good results .

That's my .02 and I'm sticking to it .

-Nate
Nate

Nate,

You are completely right about the carbon black in tires. And they use much less of it today in the rubber "mix" than they did 20 years ago. That's why tires tend to turn brown with age much faster than they used to.

There are also a lot of other anti-oxidents that are no longer used in the mix. Anyone else notice how fast tires turn an ugly brown color if they aren't 'armor all-ed'? That's why a 20 year old tire may still *look* the same as they did 20 years ago, and a 5 year old tire may look as old as the 20 year old tire.

The price of 4 tires doesn't fix a lot of sheet metal, or even close to (heaven forbid) an ER visit...

Good Luck!!
Dave

Thanks everyone (who added value!),

Reading through the replies we have some good stuff here, but for me there is no definitive answer yet, but then there may not be one

Question#1:

Is anyone in touch with Ton Maathuis from Luxembourg? In 1982 the MG Car Club did a great day out at the Good Year Tyre test track there and Ton was working for Good Year, I would welcome his input.

Question#2

What about wire wheel inner tubes? A worse problem than tyres or not?

Phil UK,

My 25 year old tyres and were very little used I did MOT the car for a while but not much else. When I went over it and began using it I swapped for new 175 x 15 Continentals, a good brand, available in the right size and affordable. The old Michelins had no sign of cracking, I have always found that Michelins never wear out, I swapped the ones on my MGB for Uniroyals long ago (I still have them, but only because they are on original wheels that I want to keep.

My Uniroyals came off my old MGB GT and have not been used for about four years, which bothers me, but worse I don’t know when I bought them and that could have been anything from two to five years earlier.

Are you serious about replacing tyres every two years? If that is wise then almost every car over 2 years old in the UK is unsafe by your standard. My wife’s Merc is nearly three and the tyres will last perhaps another year.

Terry (New Orleans)

Your 5 year life ties in with the advice for Caravans in the UK, this looks like the best advice at the moment, but where is some definitive advice from a tyre man (see note above?).

Clifton Gordon, NC, USA,

Thanks, I will check that web site when I get some time.

John Prewer

Was it Wilde who said that "rules are for the guidance of wise men and the blind obedience of fools"? We live in a world now where we expect not to have to do anything to our vehicles (often not even check them in any way between services) and the official guidance and regulation are formulated to reflect this. The rules are there to protect us "fools" from ourselves recognising how few people actually check their tyres regularly. Of course WE all do, at least on our pride and joy, but do we do it on our daily driver? Under these circumstances a two year life simply represents the time for which we can reasonably expect to get away with such neglect. But the "wise man" checks his tyres regularly and investigates every change in appearance and sound and thus can use them for more than two years, sometimes much more. I seem to remember that in the "old days" Michelin Xs had a reputation for never wearing out. In my experience this was fairly true of the tread which went on forever (with increasing loss of grip) but the sidewalls gave way at these high mileages with potentially disasterous effects. The fool only sees the tread depth. The wise man checks everything regularly.
ian thomson

Just some more factual information: The drivers handbook of the new BMW 5 series (no, not mine...) states very clearly that tyres older than 6 years should not be used. Seems to me a very sensible rule in the light of all that has been said above.

Tore
Tore

So true ! I have a couple older sedans with old tires on them , they never go on the higway and so I'm just waiting to wear them out . my GT on the other hand I like to drive quickly in the mountains so I replace all five tires & tubes with new ones .

I routinely haul heavy scrap in my 1949 Chevy shop truck so I sprung for five new 8 ply WWW truck tires for it , it doesn't go very fast but having rolled a vehicle once I'd rather not go through that again .

I think it depends on your planned usage .

Common sense rules apply .

-Nate
Nate

This thread was discussed between 07/10/2002 and 09/10/2002

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