Arun on 21 Nov, 2011 at 10:20 AM
Referece to Formula 1 is not meant literally. He is implying for those who are interested in driving fast.
lower air pressure = more road contact (surface area increase on the road contact point) so better stability at high speeds. This will of course affect FE, steering, tyre sidewall etc. The recommended tyre pressure and tyre specs are based on the manufacturer's testing (I hope) so any deviation will have some impact which may or maynot be significant.
During high speeds/longdrives I think air inside the tyres get heated so if there air pressure is already high then there is more chance for bursting (I think this is no issue for the tubeless tyres).
Stick to manufacturers' recommendations for better performance, safety and a light wallet.
Amar K on 20 Nov, 2011 at 03:31 AM
@ Mahesh and Rohit
Thanks for input. Good question - but no answer @ least from my end cause I am no expert.
You are right that increasing air pressure from 30 to 34 will give better FE at the cost of increased breaking distance, which may cause unintentional accident due to decreased surface contact area, and less tire and road friction. I guess many people upgrade with wider and low profile tires for that reason. Friction and resistance is enemy of FE but without this car will neither steer nor stop according to Newton - that is why it is hard to control cars on snow, ice, rain and oily surface - less traction. Unfortunately, most family cars don't come equipped with rudder and parachute!
Take out your air pressure gauge, check your tire pressure. Then drive @ 150 kmph for an hour and check air pressure again - it might give some insight. Second, air thrust/lift due to high speed wind underneath the car (@ 150 kmph) tries to lift car which further decreases contact/ road to tire friction area, which may cause to loose control. I think, in most family cars due to high GC, this thrust becomes very noticeable @ 150 kmph - it is proportional to square of air speed and amount.
Please, Don't blame me for added confusion.
Rohit B.D. on 18 Nov, 2011 at 07:03 PM
Yes, even I have doubts about point 7. IMO dropping pressure might make the ride softer but it is definitely bad for handling...plus it also carries the risk of tyre blow-out. It may sound counter-intuitive, but higher pressure (within sensible limits, of course) actually protects the tyre by making the side-wall flex less thereby reducing side-wall damage. For a recommended pressure of 30 PSI, a pressure of 32-34 PSI will be better for handling and tyre safety and it also helps reduce the tyre's rolling resistance and leads to a slightly better mileage.
Mahesh on 18 Nov, 2011 at 11:55 AM
@ Amar - Can you bit explain more on your 7th point -
7. If you drive very fast, e.g., if police is chasing you in a Gypsy, reduce tire air pressure couple of notches down, car will handle better and will be in control and you will be winner in this Formula 1 race.
Amar K on 18 Nov, 2011 at 08:06 AM
An excellent topic by Rohit and very useful information - thank you. It is good to learn long term reliability of Hyundai cars in general. I totally agree with the advice of Rohit to Mahesh but for little different reason. After 4-5 years, EMI is over and insurance is cheaper, it is better to keep the car because monthly expense is so low. Even in Indian professional family, two cars are gradually becoming necessity and great convenience at the time of any emergency. However, nothing can beat two new cars every year.
Once an excellent mechanic gave me few tips to keep car looking younger over years, some of which I would like to share.
1. If you driving on rough road and you feel excessive jolting, slow down. It will reduce lot of niggling and rattling problems in long run - It will keep you and your car younger.
2. If you hear a thud after you hit a pot hole or speed breaker, you were driving recklessly - slow down. If thud occurs after slow down and second time, your shocks are bad 
. This reckless driving is the main cause of problems related to CV joints, other linkages, shocks, wheel alignment and balance. You may save few seconds but you and your car will age faster.
3. If you park your car in same position during hot sunny days in open, park one day facing wall and other day reverse it. This way, sun will bake your car paint and inside uniformly. Wash and polish your car twice a year, may once after Holi and other before Diwali. New car glow will be preserved for longer time. Buy a sun glass for your car's front screen, it will be cool to use it.
4. Regarding engine life, modern engines will last 3,00,000 Km easily. Only thing is to change engine oil as recommended by manufacturer. Always install a new oil filter when engine oil is changed - no cheap solution here. Very frequent change will make your wallet lighter without any advantage. Too long will effect engine life due to residuals. Even if you don't drive the car much, once a year is the recommendation because once oil is exposed to air after opening the seal, oil chemicals disintegrate over time. Also change air-filter @ proper mileage because filtered air is used in engine for combustion, may be more frequently if you drive on dirt roads.
5. If going for long long drive, take a short break after every few hours - it will keep you and your engine cool 
. Many rubber components loose their flexibility under constant high heat and may loose proper function.
6. Sudden acceleration and hard breaking is enemy of Newton. Inertia will take toll over years on body.
7. If you drive very fast, e.g., if police is chasing you in a Gypsy, reduce tire air pressure couple of notches down, car will handle better and will be in control and you will be winner in this Formula 1 race.
8. Using branded gasoline (like Shell), will save you in long run - no promises here.
Good luck.
Navajeevan on 17 Nov, 2011 at 09:36 PM
agian tku.
i know the limit to drive. but till now santro never give any problem even when i drive 140 km. 150 km may be the limit. i will take care ur advise to go uto 120. tku
Mod comment: Please note that you need not quote the immediately preceding post unless you want to highlight something specific in it.
Rohit B.D. on 17 Nov, 2011 at 09:14 PM
Well, even I have driven santro up to 120 kmph and found it to handle well...so I guess no issues as far as high-speed handling is concerned. But as with everything, pushing things to their limits has its drawbacks...especially if it is done constantly.
Navajeevan on 17 Nov, 2011 at 09:05 PM
tku sir,
i m driving my santro in highways upto 130 to 140. i know its dangerours. my question is whether my santro will handle it without any problem(engine problem)
Navajeevan on 17 Nov, 2011 at 09:03 PM
Navajeevan on 17 Nov, 2011 at 09:03 PM
