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Post by silverdragon on Sept 15, 2013 9:53:55 GMT
How safe is an OLD tyre.
There has been concern about the safety of old tyres, after a series of high-profile crashes have been part-blamed on Tyres....
From the simple blow-out to a separate incident causing high g-force swerve that caused tyres to fail...
It has come to the notice of several road safety concerns that there are vehicles on the road on tyres twenty years old and more?........
So, my question is, just how safe is a 20 yr old tyre?..........
Just to be plain, I now know how to check for the age of a tyre... the serial number on tyres ends with a four digit month/year age stamp in the uk, I do now check for that on vehicles I drive, and anything that DOESN'T have that age code, well, just how old are they?...
I also ask for consideration, is there actually laws around the world that deal with the age of the rubber we drive on?....
As for who are the main culprits, ...
Well, no surprise, CARAVAN towers......
Those mobile home on wheels that everyone hates?... if the caravan is 30 yrs old, its highly likely its on the original tyres.
Same with any towed trailer....
With Horse boxes and Farm equipment being the biggest group...
But I can say that at tractor speed, 15mph, its not going to be a huge accident if a farm trailer has a blow out.
So the myth to be suggested here is that if it aint broke, dont fix it....
How apt is that for aged rubber?
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Post by Cybermortis on Sept 15, 2013 13:48:57 GMT
Yes, or at least certainly there are in the US - both Federal laws and State Laws; www.ehow.com/list_5810564_consumer-tire-laws.htmlwww.safetyresearch.net/2009/05/01/srs-tire-age-bill/One thing to note, that would be a problem in terms of MB testing this, is that the fact that tires degrade is well known. As is the fact that the degree of degradation varies depending on the conditions in which it has been stored. This is likely to prove a stumbling block when it comes to MB considering testing as they don't have the time to sit around waiting for 20 years to run tests, and older tires might only be available from a scrap-yard - which is to say not exactly stored in the best of conditions. |
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Post by the light works on Sept 15, 2013 14:05:21 GMT
I had the circa 15 years old tires on my boat trailer delaminate at a very inconvenient time - which resulted in me driving to a sailing outing with the boat trailer loaded on the flatbed of my truck and the camping gear towed behind instead of the camping gear lashed onto the flatbed (minus camping trailer) and the boat towed behind. my fire department WILL retire all apparatus tires at 10 years of age; so says the rule makers. on the other side of the coin, my work truck has actually managed to pass the 1 year mark with its current set of tires.
in my experience, a visual inspection will tell you if the rubber is "aged"
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Post by silverdragon on Sept 17, 2013 8:05:01 GMT
CM, Thanks for that.
TLW, you have the idea....
BOAT trailers?...
CM, You mentioned scrap yards... a GOOD source.
The questions raised here are of Trailer tyres mostly.
Yes its a MAJOR concern if its a heavy good or other Commercial vehicle?...
But mostly the concerns are what people tow....
Boat trailers, Caravans, other trailers, left in the yard at the back of the house, in a garage, are they in perfect condition?...
Many people admit that they come to a trailer, see a flat tyre, pump it up, wait 10 mins and check....
If the tyre doesn't immediately go down again, its "Good to go"....
People towing trailers do not attach as much importance to trailer tyres as they would on the car...
Strange.
Many people put weights they would not even consider putting in a car into a trailer.... and they tow it... at the same speed as the car....
Yet the car tyres are MORE important?...
How?..
I cant figure that one myself.
The dynamics of a Commercial HGV trailer, yes, the tyres on a commercial heavy goods cab are more important than the trailer tyres, as that does more braking than the trailer...
We are taught to drive in a way that you dont do heavy braking on corners, you slow down BEFORE the corners...
But we do check the tyres of every trailer we tow, every time we hook up, and at least once a day, for damage and wear, because our "boots" are about the most important thing on the wagon... without them, we dont do straight lines very well.....
But Rollerskates?... car towing trailer often have to emergency brake on corners because its only halfway round the corner that the [fool] of a driver notices that his handling has changed...........
The law on Tyres in the US, does it actually get considered By the general public for trailers?...
Its used maybe twice a year to take garden refuse to the tip..........
The tyres LOOK new...... they have done maybe less than 500 miles.... Doest matter that the trailer is 10 yrs old.....?.... the tyres have not been used that much have they?....
Just chuck some air in they are good to go....
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Post by Cybermortis on Sept 17, 2013 12:36:04 GMT
Not really, as the tires will not have been stored in anything remotely close to ideal conditions so the best they could say would be if getting old tires from such places is a good idea or not - which it isn't unless they come off something that has just come in. (I think it is also illegal for them to sell tires that are beyond a certain age, so are unlikely to have 20 year old tires sitting around.)
Even if you keep a car outside in all weathers, the tires will get some protection from the body of the car and the wheel arch and certainly will not be getting weathered in both the inside and outside of the tire.
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Post by the light works on Sept 17, 2013 13:16:46 GMT
Not really, as the tires will not have been stored in anything remotely close to ideal conditions so the best they could say would be if getting old tires from such places is a good idea or not - which it isn't unless they come off something that has just come in. (I think it is also illegal for them to sell tires that are beyond a certain age, so are unlikely to have 20 year old tires sitting around.) Even if you keep a car outside in all weathers, the tires will get some protection from the body of the car and the wheel arch and certainly will not be getting weathered in both the inside and outside of the tire. well, for the best case I could sneak some tires out from my fire station. just because they are required to be taken out of service at 10 years doesn't mean they go away. |
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Post by silverdragon on Sept 18, 2013 6:34:43 GMT
10 yrs or 20 yrs... is there a difference....(yes probably) but how much compared to say 5yrs....... can this be shown....
Tyres stored on damp grass under a rotting trailer, or one still on a vehicle in a scrap yard.....
Do they take them off the vehicle in the scrap yard?...
I would claim not, as "Vintage" cars are probably worth more sat on the original wheel regardless of tyre condition?...
In the UK, the vehicle is left on its wheels in a scrap yard as its easier to move that way until the wheels are sold or the vehicle dismantled.
Having watched a couple of restoration programs on Vintage cars in the USA, I would say that they do leave the wheels on the car in the USA as well?...
The vehicles are sold on the condition you MUST replace the tyres.
Plus, this also brings the question, what are ideal conditions anyway, and then again, does it matter?....
There is this thing Bikers believe, if a Bike is to be wintered, it should be stored wheels off the ground, to prevent the tyre deforming....
Its different for black-snot racing tyres, they WILL distort (VERY soft rubber) but, good quality hard compound legal road tyres, as long as the tyres have air in them, the truth is, if the tyre permanently distorts by having the weight of the bike on it, that tyre is pregnant and should be replaced anyway.
I think its time to get a bunch of tyres and see what the breaking strain in lbs/sq inch is, and do that at a distance... we all seen the video of a inner tube blow havnt we?...
Then get them on a test rig and see if speed matters, then find how much braking can change the thing....
Tyre torture time...
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Post by Cybermortis on Sept 18, 2013 7:39:12 GMT
The best 'Mythbusters' way to test tires would be to get a couple of old tires, put them on an old scrap car and drive it around like a maniac (or a Kari) to see how it holds up.
I doubt that they will be able to find tires that are more than around 6-10 years old, as I seem to recall that it is illegal to sell tires that are older than this in the US. So no scrapyard is likely to hold onto tires that old. Older tires may be found on tire dumps, but sitting out in the rain for years with the weight of other tires pressing down on them is about as far from ideal conditions as you can have.
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Post by silverdragon on Sept 18, 2013 8:26:22 GMT
CM, for discussion sake, is the weight of other tyres different from say the weight of the vehicle they came off?...
Sell old tyres, illegal.
Pass them to the MB's for FREE in the knowledge they will be destructed?...(And probably recycled as well...)(Buster needs new shoes?)
Actually DRIVE on the tyres?... erm, let me think....
no.
Not even me.
I witnessed a high-speed blow out, the car span wildly, and cartwheeled..... "I wish I had a Camera" moment, shortly followed by I am glad I have a First-Aid kit....
(The driver walked away mostly unharmed... air-bags... ....priceless...)
I would rather they used the type of rig designed to test tyres and braking systems for vehicle safety checks... the wheel is span to highway speeds on a rolling road and the brakes applied in the car to see how well each individual wheel brakes...
If that kind of rig can be used, a rolling road that is rolling, and the tyre fitted to a steerable axle with a safety cover wheel arch to prevent bits flying off, it may be much safer than planking about on a runway?....
That type of rig is used to test ABS systems I believe....
That way the tyre can be tested under braking and turning forces at the same time, with extreme forces applied on a stationary rig... easier to film and a bit safer for the crew?.... (Who should be in the next room...)
And the wheel arch can be made of perspex, when that fails, a steel half inch thick one could be used.... then a one-inch thick?...
You could also vary the pressure holding the wheel to the rolling road that way, to replicate vehicle loading, and see if a heavier load creates a more spectacular fail.
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Post by Cybermortis on Sept 18, 2013 13:05:11 GMT
It is not just the weight of the tires, but that in a pile of tires the weight is almost certainly pressing down on the sides of the tire (discarded tires are stored on their sides) and that there is no air pressure in the tire to offset the weight.
Both mean that the tire will be flexed far more than it would be on a vehicle which will cause weak 'fractures' in the tire.
My point about it being illegal to sell tires past a certain age is that scrap-yards will not hold onto tires they know they can't sell. So they will either have sold them off to a dump, or a company who recycles them into road surfacing materials. They can't give you what they don't have.
As for driving. From the prospective of TV footage of a car screaming around tires smoking is far more dramatic than a stationary rig. They could remove the safety issues by running the tests with the remote rig - which they already have available. So all they need is a couple of junk cars and a few hours to rig the car up. This would allow them to do the tests on the runway and get up to speeds no sane person (or even a Mythbuster) would want to drive at on questionable tires.
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Post by the light works on Sept 18, 2013 13:34:42 GMT
a few thoughts.
flat spots are real. one of the stable of apparatus I drive is our parade engine, which only gets driven a few times a year. the first drive is always purely to "blow the creosote out of the engine" and get the tires warmed up so they go back to being round all the way around.
as for rigs to test the tires, I would think they would want to test them using the rolling bunker to tow a trailer with a breakway hitch. (as in, if the trailer gets completely out of shape, the hitch will fail and allow the trailer to go off into a random corner of the runway rather than take the bunker away with it.)
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Post by Cybermortis on Sept 18, 2013 13:50:17 GMT
A towed trailer can't wheel spin, be made to do handbrake turns ect.
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Post by the light works on Sept 18, 2013 14:02:42 GMT
A towed trailer can't wheel spin, be made to do handbrake turns ect. if only the mythbusters had someone who was skilled with remote controls they could put a motor and transmission on it; as well as a set of brakes. but really, it is more the loading and the lateral forces that will stress the sidewalls - which are the weak link. if you want to know whether the tread wears faster or not, all you need is a belt sander and a caliper. |
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Post by the light works on Sept 18, 2013 14:03:27 GMT
you could fit them on formula one cars. they expect their tires to fail prematurely.
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Post by Cybermortis on Sept 18, 2013 14:34:14 GMT
A towed trailer can't wheel spin, be made to do handbrake turns ect. if only the mythbusters had someone who was skilled with remote controls they could put a motor and transmission on it; as well as a set of brakes. So...you mean turn the trailer into an RC car? Why not save themselves a LOT of time money and effort and just get a couple of cars from the scrap-yard from the start? |
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Post by the light works on Sept 18, 2013 14:40:06 GMT
if only the mythbusters had someone who was skilled with remote controls they could put a motor and transmission on it; as well as a set of brakes. So...you mean turn the trailer into an RC car? Why not save themselves a LOT of time money and effort and just get a couple of cars from the scrap-yard from the start? well, that is assuming it is true that the biggest fail factor of old tires, particularly on trailers, is abrasion from wheelspin and skidding. |
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Post by Cybermortis on Sept 18, 2013 15:42:44 GMT
So...you mean turn the trailer into an RC car? Why not save themselves a LOT of time money and effort and just get a couple of cars from the scrap-yard from the start? well, that is assuming it is true that the biggest fail factor of old tires, particularly on trailers, is abrasion from wheelspin and skidding. Two reasons why spinning the wheels and skidding around is a viable way to test tire strength for MB; 1; Time, MB only have 7-10 days to film a segment, so they would need a test that doesn't take forever to run. Even a 'weakened' tire may not fail for several thousand miles - meaning that normal driving or a rig that simulates normal driving would simply take far too long to test. Pushing the tires to their limits drastically increases the odds of them failing, which translates as a fairly short (and fun) test. 2; Visual element; A car burning rubber and belting around a track (or runway) makes for much better TV, as would what happens when/if the tire fails. Watching MB watching a static rig or just driving slowly around a track for hours would be far less interesting - if you look back you may notice that in the past when they have done such tests they tend to cut a hell of a lot of footage of such driving out or they go out and drive on the roads (so they can get footage of the SF area rather than the same track over and over and over). Nothing wrong with a static rig to get general data on the condition of tires, but for the end testing rocketing around a track would look a lot more impressive - and much more fun for the cast even if they are using an RC rig. |
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Post by the light works on Sept 18, 2013 15:52:15 GMT
well, that is assuming it is true that the biggest fail factor of old tires, particularly on trailers, is abrasion from wheelspin and skidding. Two reasons why spinning the wheels and skidding around is a viable way to test tire strength for MB; 1; Time, MB only have 7-10 days to film a segment, so they would need a test that doesn't take forever to run. Even a 'weakened' tire may not fail for several thousand miles - meaning that normal driving or a rig that simulates normal driving would simply take far too long to test. Pushing the tires to their limits drastically increases the odds of them failing, which translates as a fairly short (and fun) test. 2; Visual element; A car burning rubber and belting around a track (or runway) makes for much better TV, as would what happens when/if the tire fails. Watching MB watching a static rig or just driving slowly around a track for hours would be far less interesting - if you look back you may notice that in the past when they have done such tests they tend to cut a hell of a lot of footage of such driving out or they go out and drive on the roads (so they can get footage of the SF area rather than the same track over and over and over). Nothing wrong with a static rig to get general data on the condition of tires, but for the end testing rocketing around a track would look a lot more impressive - and much more fun for the cast even if they are using an RC rig. so you get a low slung trailer and load it to about 25-50% over the tire rating and run it as hard as the truck will tow it. that pushes the tires harder to the relevant limits than breaking traction does. they could even put an aged tire on one side and a fresh tire on the other; and see which blew first. |
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Post by silverdragon on Sept 19, 2013 6:27:23 GMT
Good plan Stan.
Heh heh heh... come watch me flip a trailer.....
Jackknife... its the handbrake turns of trailer towing.
No seriously, I got out of shape one time on loose surfaces and got a car trailer going sideways, I think I could replicate that....
Car trailer, one that you put a car on?... such as the ones used to tow a show car or racing car....
No car was on it at the time, and they do have a low centre of gravity.
As for full sized 60ft box trailers.... no.
I wont be doing tricks with one of them...
When they start to go sideways, you are more or less a passenger....
Stress Fractures.
Yes....
Or Age related fractures.
Rubber deteriorates....
Anyone who has older tyres that has ripped them apart will tell you that after a certain age the rubber just crumbles away, it looses its elasticity, and you get that spiders web of cracks.
But at what point does that become visible?....
The thing we are more or less looking for here is tyres that APPEAR to be ok, but have started to deteriorate "inside" already.
Cyber, one more point, not all scrap yard tyres are off the vehicle....
In the UK, tyres and wheels are left on the vehicle as long as the vehicle remains a moveable object?...
If only for the fact they give a space underneath to get a fork-lift.
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Post by Cybermortis on Sept 19, 2013 12:20:44 GMT
I don't think any scrap yard in the UK or US is going to keep a car that intact for a year, let alone years. In terms of space cars usually get stripped down of anything that could be sold off fairly quickly. In the case of the wheels they'd be more interested in the rims than the tire itself.
They may of course have cars that had been left lying around for years before being taken away - which would have older tires on them.
Musing on this though, MB *might* have access to an ideal source of older tires in reasonable condition - the impound lot. It is possible that some cars may have been kept in storage for long times (especially if they were involved in a criminal case). They may be able to come to an agreement where they can take some of those tires - if they agree to replace them, which if the police were looking to sell the cars on they might have to do anyway. Another possibility might be the military, more specifically the vehicle storage dumps the USM maintains. They may have old tires either on some of the vehicles that are in storage or even stores of older tires they never got around to disposing of. Although these tires would most likely not fit on a modern car*, it might still be a viable source of some very old tires to show how badly they can degrade. The military might also have better records when it comes to old tires, and if it comes down to it *might* be willing to sacrifice and old vehicle or two they would otherwise have just used for target practice.
(*This could be another reason why a trailer might not be a viable test - trailers don't usually use the same size wheels as cars.)
A towed trailer could also prove to be more dangerous than just using a car with old tires. If it is solidly connected to a vehicle and jackknifes it could take the vehicle with it. It is isn't solidly connected they would not be able to do much more than drive in a straight line - and if you have to brake hard there is nothing to stop the trailer before it slams into the back of the vehicle.
A car gives more options in terms of testing, and is safer all around even without an RC rig - although using the rig would remove the need to heavily reinforce the compartment in case it flips over which would save a lot of time and effort so would be the best option I think.
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