Older tires--lightly used--replace anyway?
#41
I hope that's a rhetorical question, because an answer is light years away from me! My first guess would be that every other constituent would be proportionally reduced in percentage terms, but I have no real idea. The major constituents make up about 99% of the atmosphere, but that last 1% contains thousands of things.
#42
@ DocDsXK Thread Starter : YES you should.
Besides all the interesting and valid theory in this thread I can report form reality:
My XK 5.0 had 8 years in hot/sunny climate (Florida). But only 10tmls. Tires looked as new (probably not under a microscope though) and were perfectly legal.
Then I noted (now in Europe) that the car tended to spin when accelerating out of roundabouts etc.
So bad that I first wondered whether I have oil on the tires, the anti-spin not working or suchlike.
Changed to new Dunlops. Astonishing impact really. Would never have expected THAT big difference.
Take the (very modest) cost of providing your cat with proper “shoes” !
Besides all the interesting and valid theory in this thread I can report form reality:
My XK 5.0 had 8 years in hot/sunny climate (Florida). But only 10tmls. Tires looked as new (probably not under a microscope though) and were perfectly legal.
Then I noted (now in Europe) that the car tended to spin when accelerating out of roundabouts etc.
So bad that I first wondered whether I have oil on the tires, the anti-spin not working or suchlike.
Changed to new Dunlops. Astonishing impact really. Would never have expected THAT big difference.
Take the (very modest) cost of providing your cat with proper “shoes” !
And sure, new tires are always better.. We change to NEW tires for EVERY race weekend in competitive standings situations. But the "cost of providing your cat with proper “shoes” 🙄 is not what everyone would consider "very modest" - to say the least. Great discussion - and simply my opinion.. All the best.
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peterv8 (01-21-2021)
#46
#47
I store my XKR all winter long, too. Why not replace this set with a HP or UHP Summer tire as I have done?
My Audi A8 is my daily driver... I have a set of dedicated summer tires/wheels and a set of dedicated winter tires/wheels. The car performs at maximum capability throughout the year. I do this for safety reasons, not adolescent street-racing intimidations. As indicated above, I want to be able to maneuver away from the bald-tire demolition derby contestant.
Being an Akron, Ohio native, tires are in my blood. They are the only thing connecting you to the road. Compromised or less than ideal tires can negate every other aspect of any otherwise perfect car.
My Audi A8 is my daily driver... I have a set of dedicated summer tires/wheels and a set of dedicated winter tires/wheels. The car performs at maximum capability throughout the year. I do this for safety reasons, not adolescent street-racing intimidations. As indicated above, I want to be able to maneuver away from the bald-tire demolition derby contestant.
Being an Akron, Ohio native, tires are in my blood. They are the only thing connecting you to the road. Compromised or less than ideal tires can negate every other aspect of any otherwise perfect car.
#48
Hi, I agree about the concern while driving at high speed. I just checked my tires I have three 26/14 and one 25/14. So, they are six years old. Tires looks good, plenty of treads. So, I'll replace them once I get my stimulus check. Again, thank you. I'm working on securing my Seat Module under the passenger seat that's loose. Broken bracket but works. I read that is a common issue. Dealer wants $850,no way.
#49
I'll pile on briefly to say that I have 25 year old tires on my 74 Jaguar and they will be replaced if I ever drive it off the mountain I live on. However, when I purchased my 01, it had low mileage premium Pirellis on it, BUT they had been on for a long time on the very-low mileage car. And, it was in the desert, although parked in the summer I believe. Regardless, I blew out a rear tire on the freeway at about 75+ MPH. It had split right down the middle and it wasn't inflation. I immediately changed out the tires.
An interesting parallel in the boating world: deck shoes lose their grip and the sole gets slippery after about two years. The compound just hardens. It's a bit scary.
An interesting parallel in the boating world: deck shoes lose their grip and the sole gets slippery after about two years. The compound just hardens. It's a bit scary.
#50
Rick, does this mean you never drive it or you'll only change the tires after the crash? If the latter, as your server, may I suggest the pork tartare for your main course??
Last edited by Bill Mack; 01-21-2021 at 03:46 PM.
#51
6 year old tires are not dangerous! If tires would go bad after only 6 years I believe there would be a law for driving with old tires. There was a test in a Swedish magasin a couple of years ago between new winter tires vs 10 year old winter tires. They were suprised the 10 year old tires behaved so good, they were not far the the new.
#52
With a bit more research I came up with these recommendations that in the end put the onus on the consumer (of course). I was looking to see if there could possibly be some form of "integrity test" to sort out if a tire was still in sufficient health to remain in service. There is NO such thing. I do remember years ago that plane wings used to be tested by placing heavy sandbags on them. If they held up then they were good to go. What was eventually discovered was that the weight of the sandbags produced microcracks in the wings that led to failure sooner. Modern testing for wing metal fatigue was changed to sophisticated non-stress testing with ultrasonic, x-ray and magnetic particle devices. None of this is available for tire testing and stress testing a tire with heat and high pressure/O2 will just lead to failure sooner. I think a "tire biopsy" could help diagnose the health of a tire but in the end the cost of doing such a thing ends up prohibitive compared to just getting new tires.
The conclusion of the compiled reference below is that at 6 years you need annual tire assessments by a "tire professional" but even a tire professional cannot detect internal weakness that may lead to failure. At 10 years it is recommended to dispose of the tire. Figuratively and literally YMMV!
I've included the references and a quick summary for those that are interested...https://continentaltire.com/learn/ho...does-tire-last
Continental is unaware of any technical data that supports a specific tire age for removal from service. However, as with other members of the tire and automotive industries, Continental recommends that all tires (including spare tires) that were manufactured more than ten (10) years previous be removed from service and be replaced with new tires, even when tires appear to be usable from their external appearance.
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https://www.bridgestoneamericas.com/...ire-inspection
Depending on how much you drive each year, your tire’s tread may last for years but just because the tread is not worn out does not mean that your tires don’t need to be replaced. Bridgestone, following industry standards, recommends that tires be removed from service no more than ten (10) years after the date of manufacture.
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https://www.tirereview.com/wp-conten...TSAs_Work1.pdf
First is degradation of the rubber compound and material interfaces due to the effects of heat and reaction with oxygen (thermo-oxidative aging). The second is the effect of cyclic fatigue during tire deformation, which can initiate and propagate cracks and separations
The most frequently occurring failure was cracking in the shoulder (55.6 percent), other failure modes observed were: cracking in tread groove (22.2 percent), cracking in base of tread at shoulder (18.5 percent), tread separation at shoulder (18.5 percent). Smaller percentages of tread shoulder blister, tread chunking, cracking in sidewall, sidewall delamination, sidewall bubbles, sidewall deformation at splice
In summary, NHTSA’s main findings with regard to tire aging can be listed as follows: • The aging mechanisms that are most likely to affect the relative safety of a tire are chemical and mechanical in nature. Chemical aging occurs due to the combined effect of heat and oxygen on the rubber compound and mechanical aging results from the stresses and strains that a tire incurs during its normal use. • In the warmer parts of the United States where we have data, including Arizona, Florida, Texas and Southern California, there appears to be a relationship between the age of the tire and the propensity of the tire to fail. • Tire aging failures tend to appear in the high heat states, in the summer months, during the day, while the vehicle is being driven at highway speeds. All of these factors make it more difficult for the tire to dissipate heat, and heat build-up is the main factor in these types of failures.
At this time, the agency does not believe it is necessary for motor vehicle safety to add a tire aging requirement to its light vehicle tire standard due to the following reasons: First, FMVSS No.139 has contributed to an increased robustness of oven-aged light vehicle tires. Our research has shown that oven-aged FMVSS No. 139-compliant tires are more resistant to degradation than oven-aged pre-FMVSS No. 139 tires. Second, light vehicle tires are performing better on the road as reflected in our most recent crash data. Third, a mandatory TPMS on light vehicle tires 30 since 2007 has helped alert consumers to under-inflation, which is also known to degrade tires faster.
-------------------
https://www.safercar.gov/Vehicle-Sho...ing/Tire-Aging
Continental is unaware of any technical data that supports a specific tire age for removal from service. However, as with other members of the tire and automotive industries, While tire life will ultimately depend on the tires’ service conditions and the environment in which they operate, there are some general guidelines. Some vehicle manufacturers recommend that tires be replaced every six years regardless of use. In addition, a number of tire manufacturers cite 10 years as the maximum service life for tires. Check the owner’s manual for specific recommendations for your vehicle. Remember, it is always wise to err on the side of caution if you suspect your vehicle has tires that are over six years of age.
The conclusion of the compiled reference below is that at 6 years you need annual tire assessments by a "tire professional" but even a tire professional cannot detect internal weakness that may lead to failure. At 10 years it is recommended to dispose of the tire. Figuratively and literally YMMV!
I've included the references and a quick summary for those that are interested...https://continentaltire.com/learn/ho...does-tire-last
Continental is unaware of any technical data that supports a specific tire age for removal from service. However, as with other members of the tire and automotive industries, Continental recommends that all tires (including spare tires) that were manufactured more than ten (10) years previous be removed from service and be replaced with new tires, even when tires appear to be usable from their external appearance.
-----------------------------------
https://www.bridgestoneamericas.com/...ire-inspection
Depending on how much you drive each year, your tire’s tread may last for years but just because the tread is not worn out does not mean that your tires don’t need to be replaced. Bridgestone, following industry standards, recommends that tires be removed from service no more than ten (10) years after the date of manufacture.
-----------------------
https://www.tirereview.com/wp-conten...TSAs_Work1.pdf
First is degradation of the rubber compound and material interfaces due to the effects of heat and reaction with oxygen (thermo-oxidative aging). The second is the effect of cyclic fatigue during tire deformation, which can initiate and propagate cracks and separations
The most frequently occurring failure was cracking in the shoulder (55.6 percent), other failure modes observed were: cracking in tread groove (22.2 percent), cracking in base of tread at shoulder (18.5 percent), tread separation at shoulder (18.5 percent). Smaller percentages of tread shoulder blister, tread chunking, cracking in sidewall, sidewall delamination, sidewall bubbles, sidewall deformation at splice
In summary, NHTSA’s main findings with regard to tire aging can be listed as follows: • The aging mechanisms that are most likely to affect the relative safety of a tire are chemical and mechanical in nature. Chemical aging occurs due to the combined effect of heat and oxygen on the rubber compound and mechanical aging results from the stresses and strains that a tire incurs during its normal use. • In the warmer parts of the United States where we have data, including Arizona, Florida, Texas and Southern California, there appears to be a relationship between the age of the tire and the propensity of the tire to fail. • Tire aging failures tend to appear in the high heat states, in the summer months, during the day, while the vehicle is being driven at highway speeds. All of these factors make it more difficult for the tire to dissipate heat, and heat build-up is the main factor in these types of failures.
At this time, the agency does not believe it is necessary for motor vehicle safety to add a tire aging requirement to its light vehicle tire standard due to the following reasons: First, FMVSS No.139 has contributed to an increased robustness of oven-aged light vehicle tires. Our research has shown that oven-aged FMVSS No. 139-compliant tires are more resistant to degradation than oven-aged pre-FMVSS No. 139 tires. Second, light vehicle tires are performing better on the road as reflected in our most recent crash data. Third, a mandatory TPMS on light vehicle tires 30 since 2007 has helped alert consumers to under-inflation, which is also known to degrade tires faster.
-------------------
https://www.safercar.gov/Vehicle-Sho...ing/Tire-Aging
Continental is unaware of any technical data that supports a specific tire age for removal from service. However, as with other members of the tire and automotive industries, While tire life will ultimately depend on the tires’ service conditions and the environment in which they operate, there are some general guidelines. Some vehicle manufacturers recommend that tires be replaced every six years regardless of use. In addition, a number of tire manufacturers cite 10 years as the maximum service life for tires. Check the owner’s manual for specific recommendations for your vehicle. Remember, it is always wise to err on the side of caution if you suspect your vehicle has tires that are over six years of age.
Last edited by DocDsXK; 01-21-2021 at 11:21 PM.
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Bill Mack (01-22-2021)
#54
#55
Sulfur is still the most commonly used compound for curing, or vulcanizing, raw rubber during the manufacture of tires. Other compounds - called accelerators and activators - speed the process of vulcanization, but sulfur is still the key ingredient.
#56
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Bill Mack (01-22-2021)
#57
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Huntervision (02-06-2021)
#58
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Huntervision (02-06-2021)
#59
Jay Leno Talks About Old Tires
https://www.hagerty.com/media/opinio...ut-1200-tires/
This is what Jay Leno found out about old tires from experience.
This is what Jay Leno found out about old tires from experience.
#60
https://www.hagerty.com/media/opinio...ut-1200-tires/
This is what Jay Leno found out about old tires from experience.
This is what Jay Leno found out about old tires from experience.
Last edited by bocatrip; 07-11-2023 at 09:40 AM.