Older tires--lightly used--replace anyway?
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From: Kaysville, Utah, US
Any other questions? Besides, I haven't taken a science class in forty years.
AND, I also inject more helium, just over 2% to make the tires lighter.
..... so there....
While the atmospheric pressure varies sensitively with altitude, the composition of the atmosphere (percentages of various constituent gases) does not vary until the so-called ozone layer is encountered, at between 20 and 40 kilometers in altitude. The atmosphere has fewer molecules of nitrogen and oxygen as you go higher (less pressure) but the relative ratio between the two elements is the same for at least the first 20,000 meters of altitude.
And, sorry, but nitrogen is lighter than oxygen...
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From: Atlanta suburbs
Seriously, very clever. Thanks.
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From: South County Rhode Island
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From: Rochester NY
Tires
I have no expertise however, I recently bought a 2010 XK with very low mileage and original tires in great shape visually. I took it yo the Jag dealership to have them go over the entire car. They recommended tire replacement.
I did so and the difference in road noise snd handling was night snd day. I also feel safer but it’s just a feeling.
QUOTE=DocDsXK;2342683]Should I replace tires based on tire age alone? Replacing tires every 6 years regardless of wear seems to be a not uncommon recommendation. I have about 6000 miles on my 7 year old Continental Extreme Contact DWS. Excellent tread, no sidewall cracking, no uneven wear, no sign of any damage. Garaged car with very limited harsh weather and UV exposure. I know that tire compounds do deteriorate with time but throwing these "good looking tires" away just seems wasteful.
Regards[/QUOTE]
I did so and the difference in road noise snd handling was night snd day. I also feel safer but it’s just a feeling.
QUOTE=DocDsXK;2342683]Should I replace tires based on tire age alone? Replacing tires every 6 years regardless of wear seems to be a not uncommon recommendation. I have about 6000 miles on my 7 year old Continental Extreme Contact DWS. Excellent tread, no sidewall cracking, no uneven wear, no sign of any damage. Garaged car with very limited harsh weather and UV exposure. I know that tire compounds do deteriorate with time but throwing these "good looking tires" away just seems wasteful.
Regards[/QUOTE]
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From: Texas
I recently had the acid test on this very thing on my 1997 XJ6. I is as close to a daily driver as I get, since I really only venture out a couple of times a week. The tires were really good from a visual stand point. but I had warning, it would spin a little coming out of some stops on rainy days. The traction control would get me moving, so I dismissed it. Then came the event, in the rain, about 50 mph, on a secondary road going through one of my favorite S bends, the rear kicked out violently, threw me into the oncoming lane, which thankfully was unoccupied. Worse yet the skid wouldn't break, none of my tricks worked, and a ditch was coming up. I finally went against my experience, and training, and mashed the brake. That broke the skid, the chatter from the anit-locks made it bite again, and we were saved. I drove home sedately, and got on the phone to my tire shop, the next trip out was for new tires.
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From: Dallas
I think CO2 is now closer to 0.041%. But I wonder what it has replaced?
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From: Lake George, NY
Driving your Jaguar less than 1,000 miles a year is the problem!
[QUOTE=DocDsXK;2342683]Should I replace tires based on tire age alone? Replacing tires every 6 years regardless of wear seems to be a not uncommon recommendation. I have about 6000 miles on my 7 year old Continental Extreme Contact DWS. Excellent tread, no sidewall cracking, no uneven wear, no sign of any damage. Garaged car with very limited harsh weather and UV exposure. I know that tire compounds do deteriorate with time but throwing these "good looking tires" away just seems
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This can be a pretty contentious issue. Some people really buy into the expiration dates. But two things cause tire rubber to deteriorate rapidly, ultraviolet light and ozone gas. Premium tire manufacturers add anti-oxidants like Santoflex to the rubber compounds that are pretty good at slowing the process. Five or six years is a good recommendation for the "typical" vehicle that's parked outdoors at mid-latitudes. That's about what I've gotten on trailer tires here in Texas. But classic and antique cars that are kept inside well-sealed and dark garages both night and day can have tires like new for decades. Its all about exposure.
There is a limit tho and if you've ever watched "Chasing Classic Cars", I do kind of cringe when Wayne pulls a half million dollar car out of a barn, barely gets it running and immediately takes it out on the highway in front of his shop on the original tires. Of course he won't change them because they're "original", but a half million dollars on the line and tires 50 years old I just couldn't do. However, I spent part of today "exercising" a $20K classic car with 20 year old tires. Just do like people have been doing since tires were invented. Inspect your tires very closely on a regular basis and keep your senses keen. If you start to see some fine micro-cracking starting to form or if you start to notice they sound different or ride different, then its getting to be about time.
There is a limit tho and if you've ever watched "Chasing Classic Cars", I do kind of cringe when Wayne pulls a half million dollar car out of a barn, barely gets it running and immediately takes it out on the highway in front of his shop on the original tires. Of course he won't change them because they're "original", but a half million dollars on the line and tires 50 years old I just couldn't do. However, I spent part of today "exercising" a $20K classic car with 20 year old tires. Just do like people have been doing since tires were invented. Inspect your tires very closely on a regular basis and keep your senses keen. If you start to see some fine micro-cracking starting to form or if you start to notice they sound different or ride different, then its getting to be about time.
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Joined: Jun 2013
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From: St. Louis, MO US
Should I replace tires based on tire age alone? Replacing tires every 6 years regardless of wear seems to be a not uncommon recommendation. I have about 6000 miles on my 7 year old Continental Extreme Contact DWS. Excellent tread, no sidewall cracking, no uneven wear, no sign of any damage. Garaged car with very limited harsh weather and UV exposure. I know that tire compounds do deteriorate with time but throwing these "good looking tires" away just seems wasteful.
Regards
Regards
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Joined: Sep 2017
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From: Alberta
I recommend “exercising” the tires so they need to be replaced in 6ish years.
“stray currents” also degrade tires. My boat trailer , while enjoying the outdoors in Texas, 4 of the 5 tire got side wall cracks after 6 years(give or take). Replaced 4 tires twice in about 15 years. 2 tires north facing, 3 tires south facing. Lots of sun on the south facing. The spare tire was off the ground and never had side wall cracks. All 4 tires on the ground had side wall cracking after many years.
So, like rust never sleeps, tire degradation never sleeps either.
tires , like gas are consumables.
“stray currents” also degrade tires. My boat trailer , while enjoying the outdoors in Texas, 4 of the 5 tire got side wall cracks after 6 years(give or take). Replaced 4 tires twice in about 15 years. 2 tires north facing, 3 tires south facing. Lots of sun on the south facing. The spare tire was off the ground and never had side wall cracks. All 4 tires on the ground had side wall cracking after many years.
So, like rust never sleeps, tire degradation never sleeps either.
tires , like gas are consumables.
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Joined: Nov 2015
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From: Florida
Short and smart answer is yes, replace. Most tire establishments now have posted signs about tire age and when they will no longer work on them. Most tire manufacturers also have statements about age. I am an accident reconstructionist and 9/10 times there is a clause in your insurance policy that says coverage is void if there is defective equipment on the vehicle in the event of an accident and they will hire someone like me to find these things
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From: Houston, TX
I am not an expert, but rubber does deteriorate and the tire can look perfect but is dangerous. I read somewhere the reason for the fatal accident of Paul Walker from "2 Fast 2 Furious" was that the Porsche his friend was driving had old tires that looked perfect and they lost control because of that.
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From: Colorado
Nitrogen in tires (tyres)
So by filling your tires with atmospheric air at mean sea level (MSL) you should be getting roughly 78% nitrogen anyway unless you use air that has been stripped of O2 or fill your tires from a 100% inert gas source. Dry air is important at it removes moisture, but if your tire air is coming from an air compressor, it is already about 78% nitrogen just because that is our environment.
That is why the O2 sensor you clamp on your finger when is shows 100% absorption of O2 in your system is a reading of 21% Oxygen in your blood stream normal breathing.
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From: Pittsburgh
Should I replace tires based on tire age alone? Replacing tires every 6 years regardless of wear seems to be a not uncommon recommendation. I have about 6000 miles on my 7 year old Continental Extreme Contact DWS. Excellent tread, no sidewall cracking, no uneven wear, no sign of any damage. Garaged car with very limited harsh weather and UV exposure. I know that tire compounds do deteriorate with time but throwing these "good looking tires" away just seems wasteful.
Regards
Regards
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Joined: Aug 2019
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From: Montreux / Switzerland
Yes, change
@ 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” !