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25 Nov 08 - 07:29 AM (#2501069) Subject: BS: Aged Tires. A Video worth sharing From: Beer I bet it would be safe to say that most of you will go out and check your tires! And why not, safety is important. Beer (adrien) http://abcnews.go.com/Video/playerIndex?id=4826897 |
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25 Nov 08 - 09:43 AM (#2501155) Subject: RE: BS: Aged Tires. A Video worth sharing From: nickp OOER! Mine only last about 4 years in use but I need to check when they were fresh. Thanks for the heads up |
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25 Nov 08 - 10:16 AM (#2501184) Subject: RE: BS: Aged Tires. A Video worth sharing From: kendall I have my doubts about this. I've had tires come all untogether at turnpike speeds with no loss of control. The tires on my car are 4 years old and no sign of danger. I recently had a car with tires that were 25 years old and no problem. Looks like tabloid news to me. |
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25 Nov 08 - 10:19 AM (#2501187) Subject: RE: BS: Aged Tires. A Video worth sharing From: Uncle_DaveO I note the British warning has to do with putting tires into service after six years, not warning against using tires more than six years old. Let's suppose that a tire is sold just one month after its manufacture. And suppose that the average vehicle is driven 12,000 miles year, and suppose that actual tire wear life is estimated at 60,000 miles, that new, freshly manufactured tire should get something like five years of safe use. So if the "new" tire is sold six years after manufacture it's within that permissible sales time frame, but contemplating using it for five years, it will be eleven years old before it reaches 60,000 miles, and it would be reasonable to expect it to be safe during that life. The British warning is not, as I get it, that the consumer should remove say a seven or eight year old from manufacture tire from his vehicle, but that a tire should not be sold with a running start toward an accident. Dave Oesterreich |
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25 Nov 08 - 10:22 AM (#2501190) Subject: RE: BS: Aged Tires. A Video worth sharing From: katlaughing Thank you, Adrien! We bought new tires last year and they have never felt right to me. We've had them checked and my Rog thinks they are fine. I will now go check for the date and see what's up. Thanks, again! |
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25 Nov 08 - 03:03 PM (#2501448) Subject: RE: BS: Aged Tires. A Video worth sharing From: Gurney The tyre treads shown twice on the highway look to me like truck retreads/recaps. A common enough sight everywhere. Though of course this doesn't reduce the importance of the report, I would think that the quality of the manufacture of the individual tyre is of the ultimate importance, because everyone makes a 'lemon' sometimes. Spotting 'bad' tyres would be, I should think, impossible, since until it went, how would you know it was dangerous. How would you know from the code if it was 1991 or 2001, considering that some codes were 3-figure? I checked our car. Michelin steelbelts. Manufactured NOT in France, but in the far east. 6 years old. I can tell if a tyre is running dangerously soft, which means hot, by the feel of the car. Others may not be this sensitive, or may think they are safe until SOMEONE ELSE changes it. I also check the spare pressure every time I do the roadwheels. |
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25 Nov 08 - 05:40 PM (#2501575) Subject: RE: BS: Aged Tires. A Video worth sharing From: Little Hawk It is clear from the video that the pre-2000 labels from the 90s have only 3 numbers in the code, while the 21st century tires have 4 numbers in the code. |
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25 Nov 08 - 06:59 PM (#2501648) Subject: RE: BS: Aged Tires. A Video worth sharing From: Richard Bridge FFS! Look at the sidewalls. What state are they in? Tells you all you need to know. |
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25 Nov 08 - 09:43 PM (#2501746) Subject: RE: BS: Aged Tires. A Video worth sharing From: Charley Noble Ugh! Charley Noble |
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25 Nov 08 - 11:43 PM (#2501784) Subject: RE: BS: Aged Tires. A Video worth sharing From: JohnInKansas The difficulty with evaluating the effects of aging in tires is that there is little convincing test information on the actual effects of aging under various conditions of storage and use. The video makes much of "tread separations," but the fairly scant published information suggests that this almost always is the result of "defective assembly," before the tire went on the shelf; usually aggravated by overloading (or underinflation for the load which amounts to the same thing). Tire manufacturers (and the NHTSC) in the US do pick up separated treads off the highways for analysis to attempt to determine the causes of tire failures, and find that nearly all "shed treads" (called "alligators" by frequent highway drivers) come from virgin tires with little or no correlation with carcass age. The cause of the separation is almost always an original manufacturing defect OR underinflation for the load at the time of the failure. High speeds contribute. The main danger from "aged rubber" is probably from sidewall ruptures, and under ordinary usage conditions some "checking" and/or "flaking" of the sidewalls nearly always is visible well before the aging penetrates to/through the cord reinforcements. The tire often will show "seepage losses" well before there is much danger of "in-use catastrophic failure," if one bothers to look for it. (Seepage loss of air in transit might produce the "underinflation" that may actually cause the kind of tread loss claimed in the video, on a longer than usual trip. You may need enroute checks along with the check before hitting the road.) The main factors that produce "aging effects" in tire materials, and in other "polymer" materials, are heat and ozone/chemical exposure. Exposure to UV radiation (sunlight) also may accelerate aging. Exposure to the accelerating factors generally are minimized during warehouse storage, although careless stocking could possibly result in "unusually rapid" aging. An old rule of thumb - possibly no longer valid and NOT SUBSTANTIATED by any testing that I've heard of - is that three years in the warehouse is roughly equivalent to a year on the road, with respect to the actual chemical "aging" of the rubber. Chemical deterioration of tire polymers is greatly accelerated by exposure to sunlight, road chemicals (including exhaust chemicals and particulates, salts, and "spillages") and by heat. Underinflation (overloading at "normal" inflation is underinflation) can cause heating, which can "age" your tires rapidly. "Aging" of tires on the vehicle is so much more rapid than any similar effects in normal storage that the shelf-age of a "new" tire probably has little real effect on the "on-the-road" life you can expect. There might be a detectable effect from improper storage, but that should be "unusual." Tires of several decades ago were subject to aging to greater extent than "modern" ones, as now generally available. I knew a couple of people who "hoarded" a couple of tires when "the war" (and rationing) broke out ca 1943, who got very few miles out of them when they pulled them out in 1949 (when they finally could get gas again to drive on them); but even aging of that duration - in normal storage conditions - should have little effect on more recent tire compounds and compositions. Frequent and regular checks for proper inflation and for flaking, peeling, and/or lumps and bumps indicating internal irregularities such as ply separation etc. are still necessary, and every driver should be aware enough to sense - AND INVESTIGATE - any sudden change in "ride" that might indicate a pending tire failure. Checking the "make date" brand on new tires might be worthwhile, especially if you're dealing with an unfamiliar seller. You could pretend to be more concerned than a three or four year old date merits, just to see if you could get the seller to knock off a few bucks; but within reason (<5 or 6 years), I wouldn't worry too much about "shelf time" on modern auto tires (for non-competitive driving). John |
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26 Nov 08 - 09:09 AM (#2502002) Subject: RE: BS: Aged Tires. A Video worth sharing From: Beer John, Thank you for your contribution to this thread. Obviously you know what your talking about and found your input very interesting. Kendall, I found the video very interesting but also wondered about the validity of it. I did think that it would be interesting to start a thread on this topic as tires affect probably the most of us. Adrien |
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26 Nov 08 - 10:29 AM (#2502068) Subject: RE: BS: Aged Tires. A Video worth sharing From: Richard Bridge As John says (although he says it with scientific precision). Look at the tyre. If the sidewall shows cracking or bulges, replace it. Kick the sidewall. Inflate sufficiently and do not overload. Normally if the inflation is insufficient (or there is an overload) you will feel it in the vehicle's handling. I commonly stop after a few miles on the motorway to feel the tyre temperatures. Heat generation is a square law. Feel or any unusual vibrations or a tendency for the steering to pull, while driving. Be "vehicle sensitive". |
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26 Nov 08 - 12:52 PM (#2502182) Subject: RE: BS: Aged Tires. A Video worth sharing From: EBarnacle Having had a tire explode and damage a fender a few years ago, I certainly found the story interesting. Despite their comments, though I had no loss of control, just a mess. |
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26 Nov 08 - 03:53 PM (#2502313) Subject: RE: BS: Aged Tires. A Video worth sharing From: JohnInKansas Many decades ago, an international organization called the "Tire and Rim Manufacturers Association" published an very informative "tire and rim manual" that contained detailed information about tire and rim dimensions and load capacities. This was back when "bias ply" tires were the norm, and when "typical drivers" went about 5 or 6 thousand miles per year, and 10,000 miles per year was fairly rare. The practice among auto manufacturers then was to size tires on new passenger vehicles to get an "average tire life" of 10,000 miles. Since reducing "unsprung weight" by using the lightest possible tires (and wheels) helps to give a smoother ride, and since smaller tires were a bit cheaper, the tendency was to deliver new vehicles with tires that were, by one criterion, "undersized and overloaded" and that wore the tread off fairly quickly. Predictably, a tire sized and inflated to wear uniformly across the width of the tread gives the maximum "miles per tread;" but the tire can be safely(?) "overloaded" within limits so that the only real result is that you wear off only part of the tread. When that part of the tread is gone, you need a new tire (a bit sooner). I had access to "the book" ca. 1965 when my "new" car needed a full new set, at the predictable 10,200 miles. With a little research in the book, I found that I could step up from the original 6.70x15 tires to 7.10x15 (on the same rims), and with the larger tires I could expect "flat tread wear" and maximum tread life. My second set of tires on that car - with no other change - ran for 36,000 to 42,000 miles before replacements were needed based on the same "remaining tread depth" at end of life. I did have to change the speedometer drive gear to compensate for the change in tire effective rolling radius, since the new tires gave a reading about 11% "off" without the adjustment. (An indicated 60 mph at an actual 67 mph could result in lots of tickets?) This was at about the time that the media were touting a change to radial ply tires "because they last longer." My little experiment demonstrated that there was no significant difference between tread life if bias ply and radial ply tires were properly rated based on the same tread life criteria. There are handling differences between radial and bias ply tires that are of some significance; but it's difficult to argue that those differences were of much real significance to "average drivers" of that time. The real reason - then - for switching to radial ply tires is that the manufacturing process for radial ply tires is much more easily automated, which reduces labor cost per tire. (It should be noted that the differences in handling do require "retuning" the suspension for optimum performance with the type - bias or radial - intended. All current/recent vehicles probably are "tuned" for radials; and bias ply tires - should any such be found - should not be installed on them.) Sometime ca. 1968 Congress decided that they knew more about tires than the engineers did, so massive new regulations were imposed. To avoid "publicly contradicting" the legislators (which might incur legal liabilities), the TRMA book is, so far as I can tell, no longer published. That makes it very much more difficult to find accurate data on which users can base modifications to their tire application or can learn about proper use and maintenance of the tires that the manufacturers specify for their vehicles. It is fortunate that new materials and more consistent manufacturing methods now produce somewhat more consistent tire products, so fairly generic rules suffice for average users of most vehicles. Tire failures still occur, however, because many (most?) drivers are not really as "average" as they think they are, and ignore practices that should be observed for their "unusual use" of their vehicles. John |