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Old 27th June 2014, 23:29   #166
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Default Re: Explaining the reason behind the Taj Expressway accidents.

I think this is going .

Please read the last line of the OP

Quote:
Credit: Translated from the originally article by Manoj Gupta in Hindi published in a social networking site.
I suppose SJD@NewDelhi has nothing to do with the above test. He has just shared the information he found on a social networking site.
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Old 27th June 2014, 23:30   #167
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Default Re: Explaining the reason behind the Taj Expressway accidents.

92 degrees celcius? That's close to boiling point of water. And very close to melting point of pure rubber.

And 52 PSI?

Something not right with the numbers.
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Old 28th June 2014, 00:09   #168
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Quote:
Originally Posted by Altocumulus View Post
Another option is using nitrogen gas, when travelling on highways. Its available in most cities now. The gas doesn't expand with heat and helps to keep the tires cool as well.
Yes, you are right. Thanks for being the first in suggesting some worthy alternative.

Quote:
Originally Posted by bravo6 View Post
The pressure difference is quite high. Did you use the same guage both times?
I am trying to ascertain the same from the tester. And whether the level was likewise for all the tyres.

Quote:
Originally Posted by bravo6 View Post
Lower pressure = greater sidewall flex = more heating of the tyre.

Also lower pressure is suitable for good (smooth) roads only. If the required pressure is not met, the impact of going over huge bumps/potholes (rarity in developed countries) will be transmitted to the alloy, which may break.

On a related note, if it is raining heavily out, I don't bother to check the tyre pressure. Less pressure on wet roads gives more traction.
Quote:
Originally Posted by rajivr1612 View Post
Correct me if I am wrong.
I believe that under inflated trye will cause more flex in the side walls. This flexing over a period of time may cause crack on the side walls eventually leading to a tyre burst. The flex will be minimal on a slightly overinflated tyre.
So I guess adhering by the international standard would be faulty for good roads like the expressway too where there is minimal possibility of finding potholes? Btw Rajiv, thanks for sharing the added info. about wet roads.

Quote:
Originally Posted by singhsid View Post
Wait - isn't it more logical to just stick to the speed limit rather than advising low/high tire pressure??
Wouldn't it be more logical in assuming that any adult with a sane head would take care of his speed first instead of lesser important matters like tyre pressure and tyre tread? I have shared this for the reason of awaring the unaware about the risks of maintaining high air pressure!


Quote:
Originally Posted by wantarangerover View Post
The heat - air expands - tyre bursts part is pretty obvious I suppose. I don't know why you need any analysis to find that out.
Maybe logical to you, but I consider this worth sharing and making the numerous people who maintain high air pressure than recommended aware about the risk. However, I am still wondering if its so logical to you, why bother reading the whole thread and then investing time to put in a comment for such an illogical discussion?

Quote:
Originally Posted by Turbanator View Post
I seriously doubt this information , am yet to see these kind of low pressures in any of Cars that I own in India ( including CBU ) as well overseas .

have a look at BMW X1 pressures from a UK site

http://www.puretyre.co.uk/bmw-tyre-pressures/

Again this looks doubtful , from 30 or so to 52 - irrespective of increase in temperature in running conditions

if you have merely translated this from some Hindi newspaper or similar - definitely far from facts .
Regarding your first point, you are right. But the tester claimed 25 PSI as the international standard, not the company advised (though it would be logical to go by the company one instead of the other IMO).

And regarding your doubt, I do not agree. I ride my bike more often than I drive the family car. I hadn't maintained the air pressure of the bike tyres for more than a week, and yesterday when I went to get it filled, I was expecting a low pressure (fyi I maintain 35 PSI in the rear). But guess my surprise, when it showed 56 PSI (yes, that's right and yes, I was feeling kind of imbalanced while riding). So, if this is possible, why not possible with car tyres? Also, the article was posted personally by the tester and not by any newspaper. However, are you implying that all hindi newspapers or hindi speaking people are far from facts?
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Old 28th June 2014, 00:38   #169
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Question no.1:
Does the tyre burst if it blown to 50-60 PSI pressure? (I am sure it is not)

Question no.2:
What is so difficult to replicate this test? Had I known this thread I would've certainly tested the tyre temperature by hand (just came back from Bombay to Pune).
Above 60-70 deg C your hand cannot tolerate.

The rest is plain gas behaviour (can be approximated by ideal gas law to a great extent) P1/T1 = P2/T2 (since tyre volume is practically constant) (t = 273 + deg C)
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Old 28th June 2014, 01:18   #170
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by SS-Traveller View Post
True - the expressway authorities should put up signs saying ***Dumb researchers not welcome on this expressway***.
Language not expected from a person like you. Thanks for the other constructive points though, shall be trying to convey to the tester the same or you may do so yourself at below link:

https://www.facebook.com/manojgupta99?fref=ts

The articles about Nitrogen gas was both interesting and informative.



Quote:
Originally Posted by JoseVijay View Post
I think this is going .

Please read the last line of the OP



I suppose SJD@NewDelhi has nothing to do with the above test. He has just shared the information he found on a social networking site.
My sincere thanks for summing up the ensuing discussion so well. Neither am I the tester, nor I participated in the test in any way. I read his report and found it credible (from my recent tyre pressure experience) and hence translated and shared it in an attempt to make people aware about the intricate risk of maintaining high pressure. The speed issue is something worth noteworthy, but again attention to be attracted to the fact that I am not the tester, in fact going by the collective tone, people should believe me if I state that I drive at a speed of 25-30 in the expressway. However, Team-BHP has recently earned this popularity (?) of deviating off-topic when members who has nothing constructive to say ensue in reiterating what has already been said and dragging a matter off-topic without applying their grey-matter, and well I may earn myself an infraction for saying this but facts are facts.

Quote:
Originally Posted by smartcat View Post
92 degrees celcius? That's close to boiling point of water. And very close to melting point of pure rubber.

And 52 PSI?

Something not right with the numbers.
Yes, by the facts presented by you along with a few other posts, I am forced to think there is some iota of doubt in the figures. Shall take this up with the tester for clearing the doubts.
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Old 28th June 2014, 01:32   #171
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Default Re: Explaining the reason behind the Taj Expressway accidents.

We had the TPMS installed on our Ikon a couple years back. While it was new I once measured it on the expressway from our home to Pune. The increase in the air pressure was of about 10 to 12 PSI while the temperature showed a similar increase too.

Also the Ikon has pretty high cold air pressure compared to the Nano, so making statements like 25psi as per international standards is a load of bs methinks. Also 25psi is most surely on the lower or underinflated side. What if the same test were to be conducted with the cold pressure at 30psi?
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Old 28th June 2014, 08:20   #172
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by SJD@NewDelhi View Post
We got the BMW X1 SUV from one of our team-members for the test. Please keep in mind, the original focus would be on the tyres. First, we checked the pressure of the tyres and set it to 25 PSI, in accordance with the international standards (cars in all developed countries maintain this pressure level diligently while most of the people in our country are either not aware of this or maintain pressure level as high as 35-45 PSI in order to get higher fuel economy). Now lets get on with the test at hand.
Where did you get the figures in bold? Can you show us the tyre placard of the X1? That is ridiculously low tyre pressure settings by any standards for motorway driving for any car.

From what i could gather on the internet the tyre pressure for the X1 with 225/50/17 tyres is 32PSI front 38PSI rear. It might be different for India but it is never going to be as low as 25PSI (unless you or the bad-informed tester translated 250kpa on the placard as 25 psi).

To TBHPians:
Do not set your tyre pressures to 25PSI or lower than recommended for any motorway driving as demonstrated in this test. If you do that you will risk a blow out. Why? Because with such a low pressure the tyre sidewall flex increase and builds up frictional heat. NO wonder the tyre pressures rose from 25 to 52PSI (if its true).

Check your owners manual for setting correct COLD tyre pressures. It will be mentioned in the manual to raise the tyre pressure for sustained high speed driving on motorways. Check your owners manual. The below picture is from Maruti Swift manual, see the highlighted section.

Mods: The thread would be correct if explaining the reason is changed to "Low tyre pressure the reason behind expressway blow outs".
Attached Thumbnails
ARTICLE: How to handle (and prevent) a Tyre Burst / Blowout-tyrepressuremaruti.jpg  


Last edited by Sankar : 28th June 2014 at 08:23.
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Old 28th June 2014, 08:31   #173
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by Sankar View Post
Check your owners manual for setting correct COLD tyre pressures.
Every vehicle will have a tyre inflation pressure placard placed somewhere around the driver's door, or behind the fuel filler flap. It is an international mandatory feature.
Quote:
Originally Posted by Sankar View Post
Mods: The thread would be correct if explaining the reason is changed to "Low tyre pressure the reason behind expressway blow outs".
+1. Readers please be warned about the perils of grossly flouting manufacturer recommendations regarding tyre pressure and other parameters prior to sustained high speed driving on expressways.
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Old 28th June 2014, 09:46   #174
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Default Re: Explaining the reason behind the Taj Expressway accidents.

I would say this article is completely misleading and would be disastrous if someone follow it. Just with thermometer and pressure gauge we cannot do the "Research" for tire blow out.

1. The average ambient temperature in western countries compared to India is much lower. So, they can have lower tyre pressure. And, they have their own regulation.

2. BMW X1 is not at all ideal vehicle to test. I hope researcher must be knowing that X1 has RunFlats and he must be aware of properties of RunFlats. To some extent RunFlat name itself suggest its meaning.

3. It must be known that lower pressure would result higher sidewall flex. It is very dangerous during high speed driving.

4. One should always follow manufacturer recommended tyre pressure in all cars. Lower pressure helps better traction and that is why the sand offroaders have to lower the pressure in their car/jeep tyres to tread through sand.

5. I would also say what SS-Traveller had said. For God sake, Highway Authority should keep away such researchers from road.
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Old 28th June 2014, 10:57   #175
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Default Re: Explaining the reason behind the Taj Expressway accidents.

I am never buying that figure of 92.5 degrees C of tire temperature. That alone makes the whole research shady. I wonder that why no one except one or two members have pointed this out?

And as pointed out multiple times in the forum, if you start with an under-inflated tire on a highway, it is a dangerous game you are indulging into. Contrary to popular belief, under-inflation of tires is the main reason for blow-outs rather than over inflation.

And 25 psi for X1? Those researchers are seriously utterly confused with the numbers I guess. Not even one number they quoted looks correct.

Edit: My car carries a placard which has some ridiculous advice on it (or I am still to make out the correct meaning of it). It says 24psi for all 4 wheels. With that pressure, the tires look so underinflated, plus the performance is nothing that I can admire. I maintain 28-30 psi all around and the service centre also agrees to it too.

Last edited by saket77 : 28th June 2014 at 11:09.
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Old 28th June 2014, 11:31   #176
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by saket77 View Post

Edit: My car carries a placard which has some ridiculous advice on it (or I am still to make out the correct meaning of it). It says 24psi for all 4 wheels. With that pressure, the tires look so underinflated, plus the performance is nothing that I can admire. I maintain 28-30 psi all around and the service centre also agrees to it too.
Are you sure its not 29 psi?
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Old 28th June 2014, 11:34   #177
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by SJD@NewDelhi View Post
Analysis: The heat produced as a result of the friction of the tyres with the road surface and the rubbing of the brake pads constantly, expanded the air inside the tyres to such an extent that the air pressure increased proportionately as a result.
Had this pseudo-researcher read Tire Bible like most BHPians, he would not have made this wrong conclusion. When you under-inflate the tyre, it results in excess sidewall flex. When drive with this excess sidewall flex, the constant flex and unflexing of the tyre results in excess heat. That is why slight over-inflation is recommended on long highway drives.
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Old 28th June 2014, 12:38   #178
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Default Re: Explaining the reason behind the Taj Expressway accidents.

A lot of loop holes in the research.

1. Assumption that all accidents are because of tire bursts,

2. Wrong choice of vehicle. Why flaunt the BMW? Hardly among the common vehicles on the road.

3. Wrong air pressure to start with. The X1 would carry a placard somewhere stating the correct tire pressure. The researcher not only deviates from this instruction, but also thrashes the general public for running on incorrect tire pressure - where in the first place, he is himself on the wrong foot.

4. 25 psi as International tire pressure standard? Since when? I always thought that it is the manufacturer, vehicle and the tyres which decide the pressure rather than the UN!

5. They maintained high speeds. How high - not stated. For me anything above 80 is high. For my wife, even 50 is high. For some, 140 is pleasant. Whatever, but the researcher first blames the Indian general public for running tires at high tire pressure, and now he happily accepts maintaining 'high speeds'. The speed limit on this highway is 100 KMPH.

6. The expressway is about 165 kms long. The research team covered this distance in 2 hours; averaging about 80 KMPH. Wonder what high speeds they are actually talking about? Substantiates what I said - high speed is a relative term.

7. After this trip, tire pressure figures got inverted - from 25 psi to 52 psi. I am not a math expert, neither a Physics student. Cannot comment if air pressure can double. But if it can, then one can start with as low as 15-20 psi and still get over-inflated tyres by the time he is done with his drive.

Quote:
Now the question arises as to why the tyre pressure increased so drastically
8. Black magic someone?

9. 92.5 degrees C as tire temperature. A little more and its boiling point for water. I don't believe this figure, until someone proves & corrects me otherwise.

Quote:
Analysis: The heat produced as a result of the friction of the tyres with the road surface and the rubbing of the brake pads constantly, expanded the air inside the tyres to such an extent that the air pressure increased proportionately as a result. However our tyres, as an exception, contained air pressure in accordance with the international standards from the beginning. But for those tyres which had air pressure more (35-45 PSI) from the beginning itself or had cuts on the circumference, the probability of accident for such tyres increases exponentially.
10. An analysis apt for a 16 year old teenager on some (mass) social media sites. And what were the brake pads rubbing against? Tires? X1 having passenger train brakes?
Acc. to the researcher, 25 psi of air expanded to 52 psi, so a 35 psi air pressure will expand to about 75 psi and thus blow out. This research team is ...well, I agree with SS-Traveler!

Quote:
Hence it is submitted: Before driving on the Taj Expressway, get the correct air pressure for your car tyres and enjoy the journey safely. It is also requested of the Expressway authorities to create an awareness on this topic for all drivers on this route so that it is not their last journey.
11. So what is the correct air pressure? I am sure, according to the team it is not something your manufacturer told you. May be you can start with 10 PSI so that by the end of drive you are near 25 psi - the International standard!

And heck, why one should 'get the correct tire pressure before driving on the Taj Expressway'? I thought we should always maintain it.

Quote:
Credit: Translated from the originally article by Manoj Gupta in Hindi published in a social networking site.
Perfect for something to garner some 'likes' at a place which is in bold in the quoted text.

Last but not the least, why this research is put in context to Taj Expressway? This phenomena takes place on all roads/ highways and at all places. Hence, nothing particular to T.Expressway.

Edit: And you know what, the research team was itself on a high risk of blow out due to their ridiculous philosophies. Half knowledge is so dangerous. Heck, we would not have been reading this article due to their own half knowledge!

Quote:
Originally Posted by ankan.m.blr View Post
Are you sure its not 29 psi?
More than anything! (I have used the allocated quota of my smilies, else I would have put a smiling face here!)

Last edited by saket77 : 28th June 2014 at 12:53.
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Old 28th June 2014, 12:52   #179
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Default Re: Explaining the reason behind the Taj Expressway accidents.

It is a known issue that tyres get inflated when you drive for a longer time on the highways due to the heat produced by running of tyres & outside temperature in the daytime.

It will stay same when you are driving in the night due to the cool outside temperature which makes the tyre cool.

Hence it is a better idea to get the air checked before plying on the Highways.

We usually get our car tyres inflated to 30 whereas the manufacturer says 35 before going on a long road trip.
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Old 28th June 2014, 13:49   #180
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Default Re: Explaining the reason behind the Taj Expressway accidents.

Quote:
Originally Posted by SJD@NewDelhi View Post
We maintained high speeds. After driving the car in this manner for about 2 hours, we reached the periphery of Agra. On checking the tyre pressure before Agra, we were presented with startling results. The tyre pressure was 52 PSI.
What is the normal or expected increase in pressure on driving continuously for 2 hours?
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