[shapath]

In SANTRO it is mentioned 30 PSI in the door still i get diff views from users...so looking for clarity from BHP.
What should be the right tyre pressure for SANTRO LE which will have mostly 1 or 2 persons and AT times 3-4. is there any specific setting when it goes to hi-way. I have read that by reducing 2PSI in the back wheels will enhance driving and FE. is this RIGHT.by the way our santro TYRES are radial.TIA

[gopinathann]

I have a Santro Xing and normal pressure I used to keep is 30 psi. If you are going in highway make it 31-32 (all tyres) which will give better FE. The tyres will generate heat and expand little during long journey.

[scooby05]

Our Santro Expert??? rks please answer!

[shapath]

thanks mr gopi. you mentioned,"the tyres will generate heat and expand little during long journey". what is the effect of this on the tyre s and the pressure. can u brief. thanks.

[gopinathann]

Originally Posted by shapath

thanks mr gopi. you mentioned,"the tyres will generate heat and expand little during long journey". what is the effect of this on the tyre s and the pressure. can u brief. thanks.

During long journey tyres get heated. When tyres are underinflated mileage will be less, inferior steering response, and chances of tyre blowing out. So tyre pressure should be checked periodically atleast a week, have a check before long journeys. The 30 psi is okay for highway too, however increasing 1-2 psi will return more mileage.

Following is the cause of Overinflated and Underinflated tyres:
Overinflated: If the front tyres on a front wheel drive vehicle are overinflated, the tyre becomes hard, and the area of tyre in contact with the road is reduced. This then means that the grip of the tyre is also reduced. In bad weather, the steering becomes less positive, and the tyre will wear more in the centre, because of the overinflation. The same applies on the rear tyres of a rear wheel drive vehicle.

Underinflated:
It is actually most dangerous to drive a car with underinflated tyres. The main reason for this is that underinflation causes the tyre to become less rigid, and consequently offers inferior control to the steering functions, and ironically can cause less of the tyre to be in contact with the road surface. It is equally dangerous to both front and rear tyres to have them underinflated. Continued use under these circumstances increases the likelihood of the tyre casing breaking, as the internal heat of the tyre will increase due to the lack of sufficient air inside the tyres. Furthermore, given the increasing environmental concerns facing us all, underinflated tyres lead to increased fuel consumption.

[razor4077]

If you are using the stock 155/70/13 tyres, would suggest you stick to the recommended 30psi, but I have found the ride improves if you go down to 29 without affecting FE, control or wear & tear.
I use upsized tyres - 165/65/13, and run them at 27-28 psi. Mainly city use. For highways, as Gopi mentioned, you should increase it by a couple of psi.

Note: The above recommendation is based on my experience with Santros with 2 different tyre sizes, and some may not agree with me. This has worked well for me, so thought I would recommend the same to you.

[rks]

Originally Posted by scooby05

Our Santro Expert??? rks please answer!

I am not an expert on Santro, that is for sure. My Santro is the expert and saves my neck whenever I get into tight situations (which seems to be once too often these days).

Anyway, I agree with using recommended pressures for city and about 2 psi higher for highways.

I personally keep very high tyre pressures (35 psi) which I wouldn't recommend to others, unless they do a lot of high-speed driving. I drive at sustained speeds of 120-145 kmph on the Expressway every week and corner fast, though not to the point of tyres screeching. The Expressway covers about 40% of my driving and this driving style will tend to wear out the tyre shoulders faster. The higher tyre pressures will compensate by protecting the shoulders. I have found perfectly even wear on my S322 tubeless tyres, which I have run 19000 kms so far. The pickup, handling and FE are beter with higher tyre pressures. As the tyre tread wears out, I probably have to reduce tyre pressures to about 32 psi in the monsoon season in order to get good steering and grip on wet roads.

[WasavaTyres]

The tire pressure notings that are carried on placards on cars denote the pressure considering vehicle to be on full load. Ideally if u fill/inspect tire pressure under cold conditions (which is recommended) leave a margin of about 2 pounds for the expansion which will occur once tires get heated due to rolling resistance.