OFF THE Beaten Track

[Admin]

Very interesting article I read in Bangkokpost.com . Read all,it has some very important points. 


OFF THE Beaten Track

Changes that are needless
JESSADA TANDHASETTI

 
The other day, a story in a daily paper caught my attention. Featured was a press conference by the Ministry of Commerce dealing with the issue of quality of automobile tyres in Thailand.

Great news for the consumer. The ministry has issued a regulation that calls on makers to guarantee the quality of automobile tyres for at least four years.

Such good news that actually benefit and shield the consumer from being taken advantage of are far and few between.

Yet praise cannot be sung until the regulation comes into force and we are happy with the results.

Thai consumers have strange behaviour. It seems they don't really want to protect their rights. What's worse is that they are willing to heed advice from the seller without analysing the pros and cons.

In the end, the consumer is pressured into buying new products at a frequent rate than what is actually required.

For example, engine oil changes that should be done according to the driver's manual. Say the manual recommends a change every 12,000km, but the driver chooses to trust the proprietor of the repair shop or petrol station, both of whom benefit financially from sales of engine oil.

So they recommend a change at every 5,000km instead. It's an absolute waste of money which could be spared for other more important matters.

Tyres are the same. Their life period seems to shorten according to the recommendations of the tyre shop, mechanics or managers/owners of repair shops or aftersales service centres. All of them benefit financially from the sales of new tyres.

The immediate scenario is that the "life period of tyres should not exceed two years". This is like a plague that has spread all over. Hence, those who love their cars and care about safety, believe it without a doubt.

But this is different from the conventional engine oil change because the manufacturer did not say so in the owner's manual.

The three factors that determine the life of a tyre constitute:

- First is the depth of tyre pattern that directly influences safety while driving on wet surfaces. The tyre pattern channels out water.

I am not sure whether traffic regulations in Thailand stipulate a standard for the required depth of tyre patterns or not.

However in certain parts of Europe, the standard is a rather antiquated one millimetre. I suppose it's attributed to the lower speed capability of automobiles in the past. And tyre width was considerably narrower in the past.

A proper tyre pattern depth is three millimetres. No special equipment is required.

Use a coin, grip it with your thumb and index finger. Stick the coin into the groove pattern as your nails are parallel to the face of the tyre.

Pull out the coin and use a ruler to measure the depth of the tyre pattern. A brand new tyre has a depth of about eight to nine millimetres.

- Secondly, what determines the life and safety factor of a tyre is the level of wear to the tyre's construction or structure.

For example, the tyre was pierced by a sharp object resulting in a large tear or the tyre's structure was compromised by constantly climbing on pavements or hitting the rims.

The result is damage to the tyre structure and its walls. Tyre grinding due to flats is another reason that undermines the safety factor of a tyre.

- The third factor that tells you your tyre is no longer safe is its age from the date of manufacture.

It shouldn't exceed six years. It's actually not too long for a high quality tyre.

Those who disagree by claiming that a four-year-old tyre is already in a state of deterioration, then that's certainly a low quality tyre.

If your tyre does not fall in either of these categories, then don't worry about how many thousands of kilometres have been clocked on them.

For example, your tyres are almost four years old with a mileage of 50,000km but still retain at least five millimetres of tyre patterns - due to proper wheel alignment the tyre wear is slow - you need not rush to change them and waste your money.
Use them until one of the three factors I have described come into play. I am sure there will be arguments on the tyre material and it's tendency to become hard. It's possible and will lower its performance on wet surfaces.

Like I said, if this is the case then it's a low quality tyre which is the core of the issue of tyre quality.

I hope the ministry works on this issue diligently to the benefit of consumers and drivers.

Jessada Tandhasetti is former department head of automotive engineering studies at Rangsit University. He holds a master's degree in automotive engineering from Technical University, Berlin, Germany.

[Lourens]

An interesting article indeed and some very good points made. But there are other factors to consider too. Tyre inflation is an important one and directly affects tyre wear. It is important to follow the manufacturers' recommendation on inflation pressures for ordinary and load use. There are mainly pick-up trucks in Buriram and I have seen many vehicles stopped on the side of the road with flat tyres especially during harvesting season when trucks are so much overloaded that the tyres can not take the pressure anymore. They overheat and burst. I once stopped at a service station to have the tyre pressures checked. The recommended pressure is 2.4 bar but the friendly assistant insisted that they be pumped up to 4.0 bar. Maybe good if you're going to carry heavy loads but for ordinary driving it's way to much. At that pressure the tyre is actually round in the middle of the tread pattern and a smaller surface is in contact with the road. Smaller surface - less traction. Less traction - poorer handling. Poorer handling - more chance of an accident. Also, when the tyre is over-inflated like that, the wear is mainly in the middle of the tread. Similarly, when the tyre is under-inflated, the wear will be mainly on the outside of the tread. Incorrect inflation - shorter tyre life. It may be worth the effort to invest in a proper tyre pressure gauge and checking those pressures yourself.

A point briefly mentioned in the article is about wheel alignment. This is also a very important factor that determines tyre life. You can think for yourself, tyres that are not properly aligned will wear unevenly. The road conditions in Buriram leaves much to be desired and driving through just one pothole at moderate speed may affect wheel alignment significantly. Even touching a curb while parking can throw wheel alignment out by a fraction. Do this several times during a years' driving and the cumulated effect could be very harmful for tyre wear. I have the wheel alignment checked at least once a year and most times it will be out by a few degrees. This is quite normal and if the alignment is set to specifications again, it will benefit tyre wear and driving safety. I have it done at the "Cockpit" service center on the west side of town not far from Taweekit. The price is only a few hundred Baht and well worth the effort in the long run.

Tread pattern depth: Many people think that a deeper tread pattern equals better grip. This is not true because as it states in the article above, the tread simply displaces water. The shallower the tread pattern, the less water can be displaced. No tread pattern - no water displacement. No water displacement - no handling on a wet road surface. Ideally, you should have a set of tyres for wet driving and a set for dry driving but realistically nobody will do that. Tyre manufacturers makes a compromise. They adjust the rubber compound softness to compliment grip on a grooved tyre. Softer compound - more grip but faster wear. Soft compound rubber is used mainly for higher performance tyres while intermediate to harder compounds are used for everyday speeds and workloads. Both tread pattern and compound hardness (or softness) also influences ride quality. An off-road tyre on a paved surface is very noisy not to mention dangerous in the wet while a road tyre used off-road will give almost no traction at all.

If you consider that four patches of rubber only about the size of the palm of your hand is all that rides between your car and the road surface and that these patches hold your safety in the palm of its hand ( ), it becomes natural that you should take better care of the tyres on your vehicle. I could go on and on…

[Admin]

Thanks Lourens, BTW - I use "cockpit" as well, they are well orgenized with all the right equipment for alignment and balance,real proffesional and the owners speaks English as well.
Father and 2 sons running the business.

cheers.