Is Your Vehicle Tyre Designed for Speed?
When disaster struck VIP vehicles, it made headline news. While some reports did touch the tip of the iceberg, the events that lead to these accidents remained unexposed. Suddenly we have, in India, not only the roads, like Mumbai-Pune Expressway in the West, Delhi-Jaipur highway in the North and East Coast Road linking Chennai-Pondicherry in the South, ideal for speeding but also the bigger, mightier horsepower engines in current models powering higher torque. Even the diminutive small cars can touch over 150 kilometres per hour when stepped on. The question is should they?
While transport vehicles are proscribed from exceeding a particular speed that is prominently painted on its side, along with the maximum load and rear axle load, car owners and drivers are totally ignorant of the fact. As long as you use OE tyres that come with the vehicle, which are mentioned in the owner’s manual, and you observe the maximum speed, you are safe. Several manufacturers however do not mention the maximum speed; where they do, the dealers’ sales staff is unaware - leave alone the end user.
Tyres too have Max Speed and Load Factor
The most important aspect of tyre safety is its permitted load and speed limitations. Till recently the tyres manufactured in India were only good for speeds of up to 150 kms/hour. MRF however has just launched the V rated tyre capable of up to 260 kmph. As per European and American safety requirements and standards, tyres are statutorily punched with an alpha-numerical coding - first the numbers that indicate the dimensions of the tyre, followed by an alphabet that rates the maximum speed which the tyre can safely withstand. It is very essential to know your vehicle’s ‘tyre speed’, because exceeding that could cause serious damage like peeling leading to a tyre burst. The second important factor is the load index - this applies more to goods carriers and transport and utility vehicles. Overloading beyond the load index could again result in a tyre burst. It would be really tragic and a deliberate act of negligence to allow such an eventuality. Other factors like a blow out caused by glass or iron pieces or other debris alone could be accidental. But at least here you will have the time to control the vehicle since there will be a minimum time of 30 seconds, before all the air exits and the vehicle veers out of control.
According to the management of a 30-year-old tyre re-treading company, fitment of altered wheels or alloy wheels of wrong specifications, fitting wrong size tyres, and even wrong alignment can cause the tyre to overheat and cleave. At speeds above 60 and even at lower speeds, sometimes, a tyre burst will send the vehicle careening out of control. A few years back a Maruti Omni toppled to the right when the rear left tyre burst in front of a ladies’ College in Chennai. The vehicle was doing only 30 kms/hour at the time, but the person driving could not control the situation, with all his experience. While his mother and pet dog were unhurt, he was not so fortunate and the skin of his right hand suffered abrasions from wrist to shoulder. Later the fault was diagnosed as over inflation of tyre pressure due to a defective gauge.
Speed Category Symbol
The speed category symbol indicates the maximum speed at which the tyre can carry a load corresponding to its load index under service conditions specified.
How Responsible are our Manufacturers?
Who is to say? But consider this: out of some leading tyre manufacturers contacted only Goodyear responded positively, providing unhindered access to the data on speed category and load index figures. On a query regarding quality control (QC) parameters and percentage of rejects, there was an ominous silence. None of the manufacturers contacted responded. The perception of the quality and safety of vehicles, individual components, and tyres can best be discerned from the remarks first of a student of automobile engineering, and the other of a CEO of UK’s leading brake oil manufacturer, both of whom visited factories in India and raised pertinent queries about ‘what is done to the rejects?’ They were shocked to hear that there were no rejects. They in turn asked me whether production skills and quality assurance in India were so immaculate that there was not even a single defect discovered. How is this possible when even in highly developed countries, be it Germany, UK, USA or Japan all manufacturers report at least a 0.01% rejection rate? A visit to an exporter of automobile components was revealing. A permanent board fixed at a prominent location gave batch-wise, product-wise figures of rejection quantities. The MD assured me that in the absence of this he would not even be short-listed by the importing company. The readers have to draw their own conclusions.
Manufacturer’s Responsibility
A suggestion to vehicle manufacturers is to include the ’speed category’ chart in the section on tyre specifications for the model, in the owners’ manual with statutory warnings on maximum speed, and importance of correct replacement. The tyre manufacturers on their part should give wide publicity to this aspect and provide a sticker to be pasted on the vehicle, probably inside the luggage compartment near the storage place of the spare wheel and tyre. In fact the tyre manufacturers association should take a proactive approach to safety and release public interest advertisement from time to time highlighting these aspects. Mass distribution of leaflets through vehicle and tyre dealers and display of the chart as POP material, and at the petrol pumps near the free air filling point, could do wonders in enhancing public awareness. Ultimately every life thus saved will be a boon to the family and relatives and be the best CRM.
