Ever since the pneumatic tire was invented, tire manufacturers have been chasing the holy grail - a tire that never punctures!
So why then do companies chase such a mirage.
The answer is cost and performance gains. Confused...read on.
If a vehicle were to have tires that would never deflate, it would make the spare tire excess baggage. And the best way to performance gains and reducing fuel consumption would be to pare off excess weight. And it may not appear so, but the weight of a spare tire, the Jack and the associated mounting-unmounting paraphernalia do add up to the weight of a young child.
To the car designers, they could very well use all this space to provide a larger fuel-tank, a better suspension or just more boot-space. For the car user, he/she would be rescued from the chore of having to attend to a flat-tire forever. And to top it off, he/she could in theory get a more fuel efficient car/ a better performing one or just one with a larger boot to take in all the adventure equipment or shopping bags.
So why then are these tires not as popular as their regular tube-less counterparts!
The answer lies in the fact that tires are a huge factor in deciding how a particular vehicle rides or handles while out on the road and off it.
So far with pneumatic tires, by virtue of the time spent understanding them, the rubber-wizards have gotten pretty good in the dark art of churning out tires that are competent enough to handle the rough and tumble of the tarmac world.
For example, a stiffer side-wall reduces flex and thereby enabling it to grip the road and corner better. However, the same stiff side-wall ensures a jaw-breaking and harsh ride. On the other hand, while a soft sidewall will flex more, thereby ensuring a cushioned ride, it will reduce available grip. Similarly, a harder compound tire will wear slower and be less prone to punctures than a softer compound tire that would wear faster and be more prone to punctures.
The tire tech guys have become well accustomed to playing one parameter against the others to get the desired performance out of pneumatic tires as per the ride/handling brief. With Run-Flats however, it is still very early in the learning curve for them. This is reflected in the ride/handling performance of the vehicles shod with run-flats and the opinion of customers the world over.
In India, the situation becomes even more peculiar. Run-Flats traditionally have a stiff side-wall and flex much less in comparison to pneumatic tires. In addition, their construction affects their ride quality in a negative manner. Besides, with the still 'under-development' nature of the road infrastructure, vehicle manufacturers are traditionally expected for setting their vehicles up in comfort-mode. To add to this, RFT's in their current stage of development cost a bomb to replace, which becomes a necessity if they deflate and are driven on.
Some, if not all of these reasons have led to two of the big three Luxury Manufacturers in India - Audi and Mercedes Benz, from offering Run-Flat Tires as OEM on their cars.
Which brings us to the remaining luxury manufacturer - BMW Motors, makers of fine driving machines that traditionally have good handling at the cost of ride quality.
BMW so far have been zealous in their promotion of RFT's on their cars. The reasons behind such a move baffle this humble tarmac worshipers mind and leave him wondering behind the premature decision to force such an ill-suitable and yet-to-be-developed technology down the pockets of the help-less Indian Luxury Car Buyer.
