[nayaksudhir]

Hi All,

There's an article on TOI today clearly inspired by frequent and recent tyre bursts in Yamuna Expressway. The author debates the tyre pressure, rolling friction, overheating of tyres (as compared to bitumen), adequate tread thickness (prescribed 1.6 MM), and some Do's and Don'ts.

While the author has quoted some PK Sikdar (former director - CRRI), the information is nowhere near Team-BHP standards and leaves much to be desired. There is no information on preferred compound, advisable tyre pressure in PSIs (while it uses ambiguous words like 'optimum' and 'adequate'), preferred brands and marks (A-Drive, C-Drive, XM2, Turanza et al).

This clearly calls for a Team BHP standard debate. Especially since most of us enjoy out ride on expressways and like to get the best out of our machines. The following points need discussion:

- Your recent experience on concrete roads wrt tyre performance

- Correct tyre pressure and recommended tyre types (specific information in PSIs and specific brands, marks, compounds)

- Speed limit for different tyre-types on concrete highways

- Performance of Run-Flats on concrete highways (recently an acquaintance just survived a BMW run-flat tyre burst on Yamuna E Way)

- DOs & DONTs (preferably quote your experience or source of information). Best Practices

- Experience if BHPians who drive on concrete highways in other countries will be invaluable

- How to sense early warning?

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

Source & Full Article

NEW DELHI: Recurring blowouts on the Yamuna Expressway and the resultant accidents have raised safety concerns among tourists and other users headed for Agra. But experts say the higher-than-usual rate of tyre failure on the expressway results from high speed and the cement-concrete road surface.

About 85% of the road is built with cement-concrete , which causes greater heating than bitumen used in city roads. So, the faster you drive, the greater the chance of a tyre overheating and bursting.

[Bigzero]

I think a fairly high number of accidents on concrete highways like Mumbai Pune Expressway will be because of a) tyre bursts and b) loss of traction on turns. I hope the govt agencies do a thorough causal analysis of all accidents that happen on major highways till date (if they arent doing so already). Somehow I get a feel that concrete highways may have higher chances of accidents.

I think the Agra Expressway is much straighter than the MPEW and perhaps instances of speeding are much higher, increasing the risk manifold. MPEW could have a fair number of accidents because of people driving faster on curved sections and losing traction.

Whatever the long-term benefits of Concrete highways are, I hate them. I dont like the excessive tyre noise, and I somehow never feel safe as the car approaches triple digit speeds.

In contrast, some of the bitumen sections on the newly laid National Highways are exceptionally good with regards to tyre noise, and evenness of the road.

I hope they make less and less of concrete roads in the future. A bitumen road designed and executed properly can last a fairly long time. The regular arguments on tar roads needing yearly overhauls and pitting during monsoons are possibly because of the high percentage of poorly laid out roads in the country. Of course thanks a lot to corruption.

[rohanjf]

The reason behind concrete roads is their durability. Once done, the highway can be ignored for many many years. Also, I think the work is lesser, as only one layer is added. So, cost should be lesser too.

This is yet another example of solving the wrong problem. Instead of laying a quality road and maintaining it, the trouble is passed on to the users.

I grew up in Mangalore, where pretty much all main roads are of concrete by now. When I was living there, I saw the road in front of my house (Bendore Well - for those who know) being concretised. The PWD's reason is, asphalt gives up easily during torrential rains.

When I drive there, I clearly feel the difference. Ride is bumpy and road resistance is high.
I am pretty sure the tyres wear out rapidly. Evident from the vehicles there!!


It is worse when the road surface suddenly changes from tar to concrete. The driving dynamics change.
When you hit a concrete patch on a highway while doing 100 kmph, you'll know the difference.

If I remember right, this was one of the crucial factors in former cricketer Azharuddin's son's bike accident and subsequent death (among other factors).

[wantarangerover]

Concrete eats up tyres fast. And regarding grip levels, its not definite - primarily depends on the quality of concrete/asphalt. So a good concrete road can have more grip than an average asphalt one, and vice versa.

[swiftnfurious]

From what I understand, concrete roads are primarily used where rainfalls are higher. I have seen some places in Kerala, which keeps breaking during the monsoons, are now converted to concrete and they hold much better. Agree that the smoothness is lesser, but on my recent drive thru Mangalore city on concrete roads, I was pleasantly surprised with the smoothness! That was the first time I ever was happy driving on a concrete road. So I guess good workmanship can take care of bumpiness & roads noise of a concrete road! But I haven't really come across any news of over heating of tyres on concrete roads.

On the other side, what is the speed limit on the Yamuna Expressway? I am sure it is sub 100 kmph! Do we really have instances of tyre burst of vehicles doing legal speeds on this road? If we push anything beyond acceptable limits, isn't damage inevitable? And how fair is a post mortem of this road construction because some people abuse it & invite accidents?

[Fiatanic]

This is really concerning. Thanks a lot nayaksudhir for bringing this up on TBHP. Filling up nitrogen will definitely help, the gas does not expand due to heat like air does. But it means that a guy driving without any knowledge of tread thickness/nitrogen should pull over every 25 kms, pour water over all the four tyres and rest for 10 minutes, will that help him prevent a tyre burst in the middle of highway?

[abhi413]

Don't there exist International / Universal standards which specify the exact composition of concrete roads? You know, just like the typical USB Port on our computers - used by all devices for compatability?

If such a standard exists, surely all our newly concreted roads are using the same specs - If so, one can hardly complain.

I haven't driven on too many concrete roads in Gurgaon. (Well, here we hardly get bitumen roads to drive on!)

But enlighten me please - do concrete roads have actually braking issues? or handling issues in rains / when wet?

[puchoo]

Well i dont think they could have given PSI specifications in the article because that is manufacturer specific and will change from car to car , so i am ok with the description used , it's upto me an owner and a driver to know what is 'optimum'

Originally Posted by nayaksudhir

There is no information on preferred compound, advisable tyre pressure in PSIs (while it uses ambiguous words like 'optimum' and 'adequate')

While i am no expert , this article clearly states that from a macro perspective concrete roads are less safe for drivers

"With regards to safety, asphalt roads provide better safety for vehicles. When compared to concrete roads, asphalt roads have better skid resistance and provide good traction. Snow melts faster on asphalt roads than on concrete roads"
http://www.differencebetween.net/obj...asphalt-roads/

Originally Posted by abhi413

do concrete roads have actually braking issues? or handling issues in rains / when wet?

[mallumowgli]

Though the article mentions problems caused due to concrete roads, the precautions mentioned are general and applicable for any tyre on any road.

Maintaining optimum pressure and taking care of the tyre wear indicator are good tyre maintenance practices. How about specific issues related to concrete surfaces.

If on the other hand there are no specific things to be taken care of, then what is the point of the article?

[NetfreakBombay]

Originally Posted by Bigzero

I somehow never feel safe as the car approaches triple digit speeds.

There is a reason for that. Road surface as well as "bank angle" of turns is never designed for such speeds in India.

In fact, some sections of MPEW have 50 kmps speed limit due to sharp turns.

Originally Posted by Fiatanic

Filling up nitrogen will definitely help, the gas does not expand due to heat like air does. But it means that a guy driving without any knowledge of tread thickness/nitrogen should pull over every 25 kms, pour water over all the four tyres and rest for 10 minutes, will that help him prevent a tyre burst in the middle of highway?

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

[SS-Traveller]

An interesting point to note, which any other Scorpio VLX owner can reconfirm and corroborate.

While cruising in a 100-110 km/h speed band on tarmac (bitumen) highways with 3 persons on board and moderate quantity of luggage, my tyres do not register a temperature above 58-60*C, even in the peak of summer (around 45-50*C in winters). On the other hand, cruising in the same speed band on a concrete highway pushes tyre temperature close to 70*C in summer. Higher speeds or higher loads, I suspect, would result in a higher difference in tyre temperatures between bitumen and concrete.

Overheating tyres, especially those with prior damage to sidewalls, MAY result in blowouts when driving on concrete surfaces.

Just my personal opinion, but I don't prefer soft compound tyres like Yokohamas or Michelins. The spinoff of a softer ride is higher chances of nicks on sidewalls, making the tyre more prone to blowouts as tyre temperatures rise. Tyre gurus please don't flame me on this!

[mmxylorider]

I don't like driving on concrete. Period. My preference is always tar roads. Pune-Mumbai solo runs are always done using old NH4.

I've found the road noise to be more and the feeling of the vehicle not planted properly each time I've used the MPEW. Also talking to couple of knowledgable folks who have participated in rallys on tires, the main thing is that the road surface should have some level of reboundness (elasticity?) that allows a much better grip and all round wear on the tires.

On an entirely different note, a blacktop with lines and cat eyes is so much more better to look and drive on.

[sgiitk]

Yes, concrete roads tend to be a bit noisier and less smooth. On the other hand the road grip may be better. I will take concrete esp. if the road is wet.

[lancer_rit]

I guess one needs more precautions when travelling on fast concrete expressways.
Proper tyre inflation for the load, and making sure you're not running on tyres whose rubber may have hardened (more than 6 years old or 60k km done, say) and can crack.

Given Yeti's unfortunate fatal blowout on MPEW, one cannot emphasize more on doing whatever is possible to keep car tyres in good condition. Rather change earlier, than try to extract a couple of thousand bucks more by running tyres for longer ?

Of course, one must also ensure more than legal tread depth (I would say atleast 2mm depth rather than the legal 1.6).

[torquecurve]

Concrete certainly hits your tyre harder than a tar road, but a few tips which a friendly driver gave me. The driver works with a car hire agency (Car Club) and were apparently trained by german instructors with videos,etc.

1. Always check the air pressure within 2 km of you starting the car in the morning or when parked in the sun within 1 km.
Reason - Tyre pressures given by manufacturers are "COLD" pressures which mean the tyre is about 15-25 degrees when checked.
2. Carry a Tyre pressure guage with you. Check the pressure when cold and then when driving. Dont every deflate the tyre when it is hot to reach 'optimum pressure'. This way you are under inflating the tyre as it is hot and so air has expanded.
3. Tyres should be rotated every 10K kms (at the most) he recommended 7 -8K kms. Ensure that you do a balancing and alignment when this happens.
4. Check tyres for FOD (Foreign object damage) regularly. A small sharp stone can easily damage the tyre if it is stuck inside the tread.
5. Drive with a 3 second (upto 60 kmph) and 5 second (60-90 kmph) rule which will allow you enough time to avoid obstacles and also reduce panic braking.
6. Dont exceed the speed limits. A 140 Kmph rated radial is rated on Tarmac and not on concrete. Use caution.
7. Nitrogen filled tyres are good. What is important is that the pressure is checked regularly. You can fill regular air into a nitrogen filled tyre (air is after all 80% nitrogen). He mentioned that most people who fill nitrogen dont check the pressure regularly which lead to under inflated tyres and that is VERY dangerous.
8. Last but not the least - Change your tyres every 40-50K Kms. Esp. if you do a lot of highway driving.

I have added some points to what he said and also explanations. But overall, I think this pretty much sums it up.