Tyre pressure adjustments on a race car are done taking into account the compound of that tyre, the ciruit it is running on, the type of car you are driving and how you want to set it up. The sole purpose is to get a quick lap time and make the tyre last the entire race.
What I'm saying here is, what works on the track will not always work on the streets.
I had a similar mindset to what Jigar has now. Take a look at my first few posts in this thread to see that. These things were built into my thought process when I was racing. While it does hold true in races e.g. you expect the pressure to rise due to the rising heat the more laps you do, hence you keep that in mind when setting up the car.
But, while race compound tyres are quick to heat up (at those speeds), they also have a very narrow window in which they operate best. That's why a race compound tyre on the streets will always be inferior in all levels of performance as compared to a sporty street tyre. The street tyre is designed keeping in mind the low speeds and spot/start nature of driving. These tyres are designed to operate within a much larger temperature window on a variety of surfaces and weather conditions.
You may think that the 45 mins you spend driving on the expressway at an average speed of maybe 100kmph (160 average is practically not feasable!) would be enough to heat up the tyres to the extent that the pressures would rise enough to cause a blow-out, hence logically you should run lower pressures to negate that rise.
The reality is that at these slower speeds, running with a lower pressure, consequently more sidewall flex, would infact create more heat in the tyre than it would if you were running the recommended pressure or even 1-2 psi more. Basically it is a matter of choosing the lesser of the two evils.
There is no fixed formula and it varies depending on the tyre, its speed rating, its profile, its compound, the car you are driving and finally the driving style. Try a few variations and you will find the best pressure needed for your car on that road. |