[vasanthn21]

Originally Posted by nayaksudhir

Hi All,

- Tips to control the vehicle in the unfortunate event of a tyre-burst.

I saw a video recently which advocated the following:

1. Do not apply brakes immediately on having a tyre burst, this might lead to the vehicle going out of control.
2. In fact, accelerate immediately on event of tyre burst.
3. Almost always, the vehicle will pull towards one side, correct this with constant steering adjustment.
4. Slow down gradually when safe and stop.

Will try to search for this video and post it here.

[debuda]

Originally Posted by scuderiamania

I have very little understanding of how a tyre reacts to different surfaces under different conditions, but there is one peculiar thing that I recently noticed will on my way back from Orissa on NH-60 which is completely concretised. We had just pulled over by the side of the road when we noticed that the surface of the tyre was unusually clean. I mean as clean as they usually are when they are in the showroom! And the tyre was definitely hotter than usual. I thought it was because off the heat from the mid day sun. I guess I was wrong. PS: Our car was running on Yokohama AVS ES 100s that are about 4 years old.

My hypothesis is that the concrete road you travelled on wasn't very smooth, and the roughness acted like a fine sandpaper to rub your tyres very clean. Due to greater friction with the rough road surface, the tyres also got abnormally hot.

Please note that the road need not look (or feel) rough, because similar to a fine sandaper the 'roughness' of the concrete surface can only be seen under a magnifying glass. I believe that most concrete roads in India are not built to very exacting quality standards and therefore the surface has imperfections. Concrete contains sand particles and stone chips -- both of which are very hard and sharp and held in an unyielding matrix of cement. The microscopic surface imperfections act like sand paper. No wonder then that Indian concrete roads make tyres hotter and rub them clean, as you personally experienced. Obviously, if you drive on such abrasive roads at high speeds, bursting of your tyres is more than likely.

Asphalt / bitumen roads also contain stone chips and sand, but they are held together in a yielding matrix of bitumen. That is why a newly laid bitumen road actually gets smoother after a few days of traffic.

[Jignesh]

Originally Posted by torquecurve

I have given a workout below.

Hello Torquecurve,

Those are eve-opening numbers. Hope atleast some of us will realise the futility of overspeeding just for a 5 - 15 minutes gain over a distance of 120 kms.

Thank for these numbers.

Originally Posted by vasanthn21

1. Do not apply brakes immediately on having a tyre burst, 4. Slow down gradually when safe and stop.

Hello Vasanthn,

Those are really good tips in event of a tyre burst & we also hope that you find & post the video demonstrating the same here.

But say if one is driving at speeds of 120 kmph & there is tyre burst, I don't think the driver will be in a state of mind to stay calm & apply these techniques. What happens is typical cycle of action & reaction where the driver actually losses total control of vehicle in bid to gain some control.

I hope you know that couple of days back we lost our T-BHP Member Sam Kapasi due a tyre burst in his Land Rover.

Thanks,

[vasanthn21]

Here is the video explaining how to respond in case of a tyre burst.

http://www.youtube.com/watch?v=lkwOE...layer_embedded

Of course, this is for heavy vehicles, but the narrator mentions that the same technique is to be used for any vehicle.

I agree with you Jignesh that in most cases the driver will immediately apply the brakes (thereby causing a calamity) as it is a natural instinct.

[Cowardly Lion]

At the outset I must clarify that I'm not an engineer nor a technically qualified person for the matter on which I'm going to give my opinion. It is given/shared in good faith.

I was on the Agra expressway recently for a joy ride with my family. While travelling on the road the first thing that I noted was that the road noise was substantial. We stopped near the F1 track and while taking pics of the family I had a look at the road very closely and took some pics as well which were subsequently lost when my SD card failed!

The road looks very nice. It has contraction joints filled with weather resistant silicon. Once I got the opportunity of looking closely at the road I realised that we weren't driving on a smooth road but a road with grooves in it. You can have a look at a similar road here - look at the 6th pic with the grooves.

The first thing that came to my mind was that if a person on Two-wheeler fell on such a road he will get the scraping of a life time. Apples to apples – a fall on such a (with grooves) concrete road will definitely hurt the person harder and scrape him/her far more severely than a similar fall on a bitumen road.

Sadly I don’t exactly recall the direction of the groove but think that they were either diagonal or perpendicular to the direction of the tyre movement. Now the grooves that I saw on the Agra expressway were pretty substantial in size (that is why my initial thoughts about falling and getting hurt). One more thing – the road was sharp to touch (vis a vis Bitumen). This could be because of the stones used in concrete or the concrete itself solidifying to that state on account of groove making.
My opinion, in light of all mentioned above, is that in case
• the grooves are perpendicular to the direction of the movement of the tyre, and
• the edges of the groove and the road at large is sharper than bitumen
Then, the road will have a higher abrasive effect on the tyre. I don’t think that the road grip will suffer substantially but in case one needs to stop in a hurry then the abrasive effect that this Agra Expressway kind of road will have on the tyres will be substantially more than a bitumen road. A skid will literally rip the tyre.I have seen and felt the road and willing to bet my money on this aspect.

If I was to develop this further then I would think that tyres that are weak/old (tread depth) will be more susceptible to damage on such roads. The road has to be seen in light of what I am saying. I mean if you rub your own palm across the concrete road you will realise the serious abrasion the road will cause.

Another thing, I think that this edgy road may have a slight ripping effect on the tyres as well nw or old. I would definitely not like to be in a car that was travelling in high 70's, completing a curve in the road & had to brake suddenly while at it.

All in all the experience was nice but this article is making me think and I for one will certainly not be hurrying on such stretches in future......

[sridhar-v]

I have experienced the heat build up, of the tyres, on concrete roads. I have a gut feeling that it is not linearly propotional to speed but some sort of exponential factor.

One experienced cab driver gave the advise of varying speed every few kilometers ranging from 60 to 90 kmph. He also said that 80-90 is the max you should push the vehicle on continuous stretches. I follow this advice to the "T".

Following points are also important:-

Check tyre pressure when cold.
Use a properly calibrated gauge as most petrol pump gauges are way off mark.
Check for stones, nails etc. in the tread.
More than 2-3 sidewall punctures ends the life of the tyre.
Change the tyre atleast when it still has 20% life left.

[debuda]

Originally Posted by sridhar-v

I have experienced the heat build up, of the tyres, on concrete roads. I have a gut feeling that it is not linearly propotional to speed but some sort of exponential factor.

The power required to propel a car increases exponentially (approximately cubic) with speed. Since much of the power is transmitted to the ground through friction between tyres and road, it is logical to assume that heat build up in the tyres would also follow an exponential pattern. Of course, the problem would be alleviated somewhat due to greater heat dissipation caused by increased air flow over the tyres at higher speeds.

In layman terms, the higher the speed, the higher the rate of heat build up for every kmph increase. To illustrate this with an example, let us say the car is running at 90 kmph and the tyre temp. is 40 deg C. When speed is increased by 10 kmph to 100 kmph, the tyre may get hotter by 10 deg C to 50 deg C. But when the car is further accelerated to 110 kmph, though the increase in speed is the same (10 kmph) the increase in temp. could be 30 deg C.

[silverado]

Concrete highways in rains are one of the most difficult roads to drive fast.

You always feel that you need a lot more distance to stop compared to bitumen highways.

Tire blowouts, are we only referring to tubetype tyres here? Do tubeless tires face blowouts?How much role does nitrogen play in this case?

I feel concrete is bad for suspension as well.

At least in Ghat section they should have bitumen for MPEW.

[sagarpadaki]

Originally Posted by silverado

Concrete highways in rains are one of the most difficult roads to drive fast.

You always feel that you need a lot more distance to stop compared to bitumen highways.

Tire blowouts, are we only referring to tubetype tyres here? Do tubeless tires face blowouts?How much role does nitrogen play in this case?

I feel concrete is bad for suspension as well.

At least in Ghat section they should have bitumen for MPEW.

Even tubeless suffers tire blow-outs if under inflated or overloaded! The role of nitrogen is little or nil in preventing blow-outs. Remember air is 78% nitrogen

[Chewbacca]

Originally Posted by NetfreakBombay

Given that air is 80% Nitrogen, there is no way that expansion would differ that much.
In fact, difference should be Zero

http://en.wikipedia.org/wiki/Charles%27s_law

Originally Posted by sagarpadaki

Even tubeless suffers tire blow-outs if under inflated or overloaded! The role of nitrogen is little or nil in preventing blow-outs. Remember air is 78% nitrogen

Until recently my Lancer ran on tubed tyres and filling Nitrogen helped me to some extent because the friction between the tube and tyre adds to the heat. Furthermore, the humidity in the air inside the tube expands more and increases the pressure.

Typically a tyre gains approx 4~5 psi for every 25 degrees celcius increase in tyre temperature. The tyre temperature v/s pressure chart is logarithmic and I have pulled the figures considering 40 degress celcius as the normal temp of tyre. This 4~5 psi deviation can affect handling, traction and FE. I have a digital pressure gauge that is quite accurate. After filling air the pressure used to increase by 8~10 psi after driving non-stop for an hour on expressways at 3-digit speeds. Then I switched to N2 and noticed that the normal/hot differential has reduced to 4-5 psi.

On highways there are many commercial vehicles still running on tubed tyres and many others with tube inside tubeless, extending the life of a their sidewall damaged tubeless .... a perfect recepe for a disaster !!

[lancer_rit]

Originally Posted by Chewbacca

The tyre temperature v/s pressure chart is logarithmic

Not sure what you mean ? Boyle's law & Charles' law applies to all gases, and essentially equates to
PV=nRT

So, Pressure is directly proportional to Temperature.
For example,
http://www.arden.org/misc/pressure.html

[Chewbacca]

Originally Posted by lancer_rit

Not sure what you mean ? ....
..... Pressure is directly proportional to Temperature.
For example,
http://www.arden.org/misc/pressure.html

The chart that I referred to, long time ago, was in Kg/cm square and in logarithmic scale and was applicable to tubed tyres. Thanks for the link which shows a nice linear chart that is much easier to understand.

Quoted from the above link ...
"a good rule of thumb is that pressure varies 1 PSI for a temperature change of 10 degrees Fahrenheit"

[Pacifica]

A very interesting thread, and I'm sure one won't find such a discussion on any other motoring site in India.

I'm currently in the US for a business meeting, and as usual rented a car for the weekend - this time it was a Hyundai Accent (what is sold as Verna in India).

Over here there is a mix of concrete and tar (bitumen) roads but tyre bursts don't seem to be all that common here. Of course, one can sense the difference in the road noise when switching from tar to concrete roads (concrete is noisier), but drivers maintain the same speeds on both surfaces without any problems.

Also, every time it comes as such an eye opener to see how people drive at high speeds (55+ mph) but in such a smooth and orderly fashion, keeping to their lanes, signalling lane changes in advance, no honking, etc. Will we see Indians maintaining lane discipline on Indian roads in our lifetimes? I wouldn't bet on it.

[debuda]

Originally Posted by Pacifica

A very interesting thread, and I'm sure one won't find such a discussion on any other motoring site in India.

I'm currently in the US for a business meeting, and as usual rented a car for the weekend - this time it was a Hyundai Accent (what is sold as Verna in India).

Over here there is a mix of concrete and tar (bitumen) roads but tyre bursts don't seem to be all that common here. Of course, one can sense the difference in the road noise when switching from tar to concrete roads (concrete is noisier), but drivers maintain the same speeds on both surfaces without any problems.

Also, every time it comes as such an eye opener to see how people drive at high speeds (55+ mph) but in such a smooth and orderly fashion, keeping to their lanes, signalling lane changes in advance, no honking, etc. Will we see Indians maintaining lane discipline on Indian roads in our lifetimes? I wouldn't bet on it.

1. Do enjoy driving in a civilized country while you have the opportunity to do so. I too have had the good fortune of driving in some European countries (including the autobahns of Germany, France, U.K., etc.) and I'm sure I won't see that kind of discipline and concern / respect for fellow motorists on Indian roads during my lifetime.
   
2. To the best of my knowledge, concrete roads in America and Europe are built using far more advanced technologies. Ability of the road to facilitate high driving speeds is an important technical consideration there. Also, they have to cater for snow / ice. They frequently use technology like Rubberized Asphalt Concrete, where old tyres are shredded and mixed in the concrete aggregate! Such roads give greater skid resistance and cause less heating and noise. You may check out http://www.calrecycle.ca.gov/tires/GreenRoads/rac.htm

[Jignesh]

Hello,

Can tyre bursts be linked to general Tyre quality in India & other developing countries? I mean in India we have pretty recently (probably in last 7 - 10 years) started driving at speeds exceeding 100 kmph, but are the normal tyres sold here capable of withstanding these speeds over long period? Also given the condition of roads (read potholes) here in India the tyres suffer much more battering than probably anywhere in the World. Add to this the fact that Roads are built with latest & better technologies in developed Countries when compared to India.

I read somewhere that in Germany there are rules to ensure that Car Owners change tyres in summer & winter seasons. Also generally tyre punctures does not happen in Germany & even if it happens then the tyres are not re-used. Infact used tyres from Germany are re-used in other countries.

Thanks,