Tyre pressure

40 is way too high. You may want to stick to the chart itself to avoid undue tyre and suspension wear & tear, if not for bumpier ride.

 

When I first received my car, it came with 40-42 PSI Tyre pressure. Came to know in my 2nd Fuel topup (had already driven 500km till then). Got the pressure adjusted to 32psi as per the Information at the Driver side door.

I do have a question. The Fuel station I do my refueling and Air Check is located about 3.5 km from my home and I usually go for filling early morning and maintain speed less than 40-50kmph all the way to the station.

Should I stick the recommended 32psi on all the 4 tyres or go for 33-34 psi on all 4 tyres?

 

3.5 kms distance with speeds @40kmph is good enough distance for a tyre not to be called a cold tyre; I suggest top up to 33psi. If you are still not convinced, fill it to 33-34psi at the station and once the tyre cools down, check the tyre pressure using a pressure gauge. Try it out couple of times and this would give you exact picture. Right now am using the below pressure gauge.

 

Thanks for the info. Also, I was checking for the pressure gauge and Found one at Snapdeal Link
Looks like the one you posted. I guess these analog one should fare better than the sub 1k digital pressure gauge. Do u have any recommendation?

Thanks for the tip. I'll surely do the testing once I get myself a pressure gauge.

--- Double Post Merged, Feb 5, 2015, Original Post Date: Feb 5, 2015 ---

I also found this online at Snapdeal Link, its Pen type pressure gauge and can measure up to 50 psi.
Between the Pen and the Analog which one would be recommendable.

Pen: Vheelocityin - Car Auto Tire Tyre Pressure Gauge Guage 50psi (Rs. 223)
Analog Dial: Coido - Car Tyre Pressure Gauge 100psi (Rs 349)

--- Double Post Merged, Feb 5, 2015 ---

Digital: Coido - 6071 Digital Pressure Tire Gauge (Rs. 629)

Of all the three, which one I can get more accurate reading.

 

There is a tyre shop about 150 meters from my house which does nitrogen filling.
Should I get my filling fine there at 32 psi or use the free air at Petrol Bunk and check the pressure personally at more regular interval.

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Two days back I drove the Shell Fuel Depot and get the tyres pressure to 33psi. Found the ride a bit not Soft. So went back today morning and set it to 32. I think I'll get a tyre pressure gauge and a small foot pump and check the tyres at home.

 

The expansion of air and nitrogen is almost same when they are hot.
Remember, Air = Nitrogen(78%), Oxygen(20.9%), Others(1.1%)
So, Filling air you are filling 78% Nitrogen. And with every topup of Air, you are technically increasing the percentage of nitrogen.

There is no scientific way Nitrogen can maintain the same pressure when there is change in temperature. The tyre guy must be repeating someone's word.
Keep it 32psi, I find even 33psi a bit bumpier to be comfortable.

 

I would beg to differ here. What you mean is every time you top up the % of N2 increases from 78% to say 80% and so on? That cannot be the case, the % of N2 does not increase after every top up. Also your statement of identical expansion of air and N2 is incorrect. When air is pressurized, the humidity in it condenses to a liquid and collects in the air storage tank you use at the local gas station. When you add compressed air to the tire, the water comes along for the ride. As the tire heats up during driving, that water changes to a gas, which then expands, increasing tire pressure. Because nitrogen is dry, there is no water in the tire to contribute to pressure fluctuations. This fluctuation is actually insignificant but there.

The main reason for opting N2 in the tyres is the saving on the loss of pressure. Since Air contains O2 which is more permeable to tyre, the loss of pressure in case of air is more than that in N2.

The main disadvantage for using N2 in tyres is ready availability. Not all bunks would have N2 filling station and this can be issue if travel is intended over longer distances.

 

A scientific test was done and here is the result.
https://powertank.com/truth.or.hype/