how old is too old for radial tires?

[Joe R.]

Re: how old is too old for radial tires?

People have the right to take their own lives into their hands and drive on unsafe tires if they want, BUT they don't have the right to take the lives of other people or children.
It is not responsible to be on the road with tires that are about the blow out, take off a fender and cause you to loose control of your Corvette.
Do you think for one minute that the cost of a tire is worth the life of a child?
Think people!

JR

[Duke W.]

Re: how old is too old for radial tires?

It's impossible to establish a single reasonable age limit for ALL tires. Congress thought about doing this a few years ago, but, fortunately, industry experts convinced them that it was unwise.

Tire quality and longevity starts with the materials and processes used to built the tire and is then dependent on their service environment.

Low quality, low speed rated tires that most vintage Corvette owners buy, using primarily cosmetic criteria, are the worst tires to start with because they lack the safety-enhancing spiral wound nylon cap belt that is common to all tires with H and above speed ratings.

Tires that are exposed to UV in a parking lot all day will deteriorate much faster than if the car is parked inside a dark garage.

Small surface cracks are not necessarily an indication that the tire is "bad" and should be replaced. Most tire failures begin INSIDE the tire, so they are impossible to see visually. If a H or higher speed rated tire does fail due to an internal defect, the nylon cap belt will almost always prevent the tire from disintegrating.

I've experienced three "tread separations" on H and above rated tires - all on race tracks - but the tires remained intact and held air. The symptom was a significant vibration and subsequent inspection revealed a big bulge in the tread. On one such failed tire I drove home the 75 miles from Riverside Raceway without incident other than an annoying vibration similar to a severely out of balance or out of round tire.

If you start out with a nylon cap belted H or above speed rated tire on a car that sees low annual mileage accumulation and spends most of its life in a garage away from UV and ozone, two to three decades of service is not unreasonable.

U. S. sourced early OE radial tires, which were not speed rated, were of much lower quality than European brand speed rated radials of the same era. Many of these early Goodyear and Firestone radials had high failure rates and several models were recalled. The first time GM installed high quality, high speed rated tires on ANY Corvette was the Z-rated Goodyear "Gatorback" on the 1984 Corvette. Prior to that, the OE tires were all JUNK!

So if you have a set of OE radials on an earlier model or run across a suitable NOS or slightly used set, be wary. I would only recommend them for shows and low speed in-town driving.

BTW, non speed rated tires only have to pass a one hour 85 MPH durability test to meet "DOT standards". That's it! Think about that the next time you are looking for a set of tires.

Duke

[Steven B.]

Re: how old is too old for radial tires?

I have a couple of friends who are tire engineers. The Michelin tire engineer advised not to exceed 3 years and the GY engineer advised not to exceed 5 years considering condition, tread, cracks, etc.

[Patrick H.]

Re: how old is too old for radial tires?

BTW, non speed rated tires only have to pass a one hour 85 MPH durability test to meet "DOT standards". That's it! Think about that the next time you are looking for a set of tires.

Duke

The problem is that there really is nothing available anymore of the tire you prefer in a size useful for older Corvettes. The Goodyear RSA is gone as is the Pirelli.
On Tire Rack and Discount Tire I count 6 different tires in 225/70, and two of those are for trucks, one is a winter tire.
We don't have much choice any longer.

[Duke W.]

Re: how old is too old for radial tires?

I have a couple of friends who are tire engineers. The Michelin tire engineer advised not to exceed 3 years and the GY engineer advised not to exceed 5 years considering condition, tread, cracks, etc.

A good engineer will not only answer your question, he will give you the reasons why.

Did they distinguish by tire quality such as speed ratings? Did they distinguish between use, such as daily driver that sits in the work parking lot baking in the sun all day versus a vintage car that's only out a few times a month.

Frankly, if the Michelin engineer says their tires are only good for three years, I would seriously question the quality of their products.

If the tire companies keep losing law suits, they will eventually recommend tire replacement more often than the car manufacturer recommends oil changes.

Duke

[Duke W.]

Re: how old is too old for radial tires?

The problem is that there really is nothing available anymore of the tire you prefer in a size useful for older Corvettes. The Goodyear RSA is gone as is the Pirelli.
On Tire Rack and Discount Tire I count 6 different tires in 225/70, and two of those are for trucks, one is a winter tire.
We don't have much choice any longer.

Last October, I just googled 225/70R-15 Firestone Firehawk PV41, and found several Web sites that claimed they had this V-rated "police pursuit tire", which had been out of production for about a year, in stock. Upon calling, most said they had no remaining stock, but I did find two that actually had some and scarfed up a set from the lowest cost vendor.

You may recall from my tire article in The Corvette Restorer from about five or six years ago, that I preferred both the appearance of this tire relative to the GY RSA and General XP2000V, and it also had a slight performance edge, particularly in the dry handling and braking tests, that DOJ performed for the benefit of law enforcement and emergency agencies in need of 225/70R-15 replacement tires for their police and emergency vehicles.

Duke

[Frank D.]

Re: how old is too old for radial tires?

[QUOTE=Joe Ray (1011);610344]People have the right to take their own lives into their hands and drive on unsafe tires if they want, BUT they don't have the right to take the lives of other people or children.
It is not responsible to be on the road with tires that are about the blow out, take off a fender and cause you to loose control of your Corvette.
Do you think for one minute that the cost of a tire is worth the life of a child?
Think people!
Why limit your thinking to just tires. If you are talking safety why not ban all cars over 6 years old. Most of these cars are driven with steering, brake, and suspension components nearing or over 50 years old. My car is rarely driven, and NEVER on any interstate or high speed highway, not over 55 mph and always on off peak hours with little traffic. I would be more concerned about the throngs of people driving while drunk, stoned or texting. My point was that tire appearance is deceiving and that has been supported here.

[Michael J.]

Re: how old is too old for radial tires?

I prefer Pirelli P4000s and have several sets on and put away, I think there are still some available out there.

[Duke W.]

Re: how old is too old for radial tires?

People have the right to take their own lives into their hands and drive on unsafe tires if they want, BUT they don't have the right to take the lives of other people or children.
It is not responsible to be on the road with tires that are about the blow out, take off a fender and cause you to loose control of your Corvette.
Do you think for one minute that the cost of a tire is worth the life of a child?
Think people!

JR

You're getting over-emotional. Go out to your nearest general aviation airport and ask the median age of the aircraft parked on the ramp. Likely it over 25 years.

Just because something is "old" be they tires or any component on a car doesn't mean they are beyond their useful service life. With airplanes, the FAA requires rigorous inspections and maintenance for the aircraft to maintain its airworthiness certificate without which, it's illegal to operate.

With similar maintenance and inspections, cars and their various parts would last as long, but high volume production lowers manufacturing costs, so it's far cheaper to replace than repair most vehicles that are over 15 years old with high miles.

For vintage car enthusiasts, it's up to us to inspect and maintain our vintage cars so that they are safe and roadworthy.

The number one cause of tire failure is insufficient tire pressure for the applied load, and no or low speed rated tires are much more prone to failure if pressure is too low for the applied load. In most of these cases, it is the owner's fault for either overloading the vehicle or not maintaining adequate pressure, but there have been situations (like the Ford Explorer fiasco of a decade ago) where tires that didnt' even meet minumum quality and DOT endurance requirements combined with low OE recommended tire pressure to offer a smoother ride on what was basically a crude pickup truck chassis - often with some degree of owner laxity on checking pressure - combined to cause a high failure rate that took a number of lives.

Duke

[Patrick H.]

Re: how old is too old for radial tires?

Last October, I just googled 225/70R-15 Firestone Firehawk PV41, and found several Web sites that claimed they had this V-rated "police pursuit tire", which had been out of production for about a year, in stock. Upon calling, most said they had no remaining stock, but I did find two that actually had some and scarfed up a set from the lowest cost vendor.

You may recall from my tire article in The Corvette Restorer from about five or six years ago, that I preferred both the appearance of this tire relative to the GY RSA and General XP2000V, and it also had a slight performance edge, particularly in the dry handling and braking tests, that DOJ performed for the benefit of law enforcement and emergency agencies in need of 225/70R-15 replacement tires for their police and emergency vehicles.

Duke

Yes, I recall the article.
However, a Google today shows only S and T rated tires. Digging for old stock has its limits, though.
FYI, one site lists 9 different brands/styles.

[Steven B.]

Re: how old is too old for radial tires?

Hi Duke. They did give detail and both noted that with the wide range of tires in quality, speed ratings, etc. their numbers considered everything from the highest, longest performing best to the lowest and worst. Their comments covered the range of manufacturers, not just their own, and addressed the "average" driver who usually has no idea how to care or maintain any part of their cars Each has done extensive testing of their brands and the competition. Much of the tires quality/performance was based upon ratings...H's don't compare to V's for longevity or performance. Composition/compunds, tire pressures, tread pattern, etc. impact the mileage and handling, as we know. Optimal scenarios for street driven tires include a high speed rating with good dry/wet tread, proper inflation. They advised to be particularly careful to inspect tires weekly and especially steel radials for broken strands (i.e. my '76 manufactured Firecstone 500's). It all pretty much boiled down to most drivers don't maintain their tires as they should and are not aware of problems that can arise.

They both advised that a high quality performance tire will likely double the usable life of a cheaply manufactured tire due to the compound, construction, etc. if properly maintained. Following that line a high quality tire may give 6, 8 or possibly 10 years with proper care and tread. My original 12,000+ mile GY's on my '78 will see low speed driving, but no interstate speeds or spirited driving. Vintage cars that don't see daily work trips usually have much longer tire life than daily drivers that are exposed to sun, pot holes, salt, etc. They also said that covering the spectrum of tire manufacturers and types high performance tires usually receive better care and maintenance by the owners and will last longer, provided the tread isn't "abused", and "ordinary" passenger car tires and non-enthusiast owned tires receive less maintenance and care and have a much higher failure rate due to neglect of tire pressure, alignment, exposure to the elements, curbs, etc.

Steve

I should have added the above is for radials. One of the engineers has vintage cars, including a '79 L-82, 4 speed, low miles original tires. They both stated that in most instances non-radial biased plys seem to hold up better in storage and on the road than the "average" radial, but the handling and performance are the draw backs.

[Dick W.]

Re: how old is too old for radial tires?

Each is entitled to his opinion about tires, but from experience I think that six years is the outside limit for radial tires operated at highway speeds. I have had two Michelins, that were six years old, separate at highway speeds. I know from personal experience they were never run under inflated nor overloaded. Conventional, non radial, tires do not seem to have an expiration date on them.

[Joe L.]

Re: how old is too old for radial tires?

I have a couple of friends who are tire engineers. The Michelin tire engineer advised not to exceed 3 years and the GY engineer advised not to exceed 5 years considering condition, tread, cracks, etc.

Steve-----


There's one slight problem with this: tires are often 1 to 3 years old when one buys them, especially for the low volume tire sizes that most Corvettes use.

[Steven S.]

Re: how old is too old for radial tires?

Steve-----


There's one slight problem with this: tires are often 1 to 3 years old when one buys them, especially for the low volume tire sizes that most Corvettes use.

If you google "dangerous tires, you will find utube 20/20 ABC segment on the subject, very interesting. After seeing it, I changed tires on 2 cars that were all over 11 years old.



Steve

[Steven B.]

Re: how old is too old for radial tires?

You are correct Joe. If you can find the performance tires you want they are a few years old in many cases. I would like to get fresh high performance tires in the range of 255X60's for my '77. My choices don't include "V" ratings and above or freshly minted tires. When we do find tires for our older cars they don't provide the performance some of us want. I won't even address the issue of my '57.

Steve