I can only presume by the answers given to this question on Quora saying not to do this that very few people have actually done the tests themselves, and blindly believe the garbage they’re fed by car and tyre manufacturers. Car manufacturers want you to feel as comfortable as possible, and tyre manufacturers want you to buy tyres.
Over-inflated tyres, and by that I mean up to 20% above the vehicle manufacturer’s specification, perform better in almost every respect. The only disadvantage is that they give a harsher and noisier ride.
Wear: My observation with many different brands and sizes of tyre on many different vehicles, is that at the recommended inflation pressure they wear the shoulders out first. You end up throwing out tyres with half their tread unworn.
Radial ply tyres have steel reinforcing wires running circumferentially, ie. in line with the main tread grooves. These wires hold the carcass of the tyre in shape across the full width of the tread, unlike cross-ply tyres they don’t bulge in the centre at higher pressures. At the recommended pressure the shoulders have significant support from the sidewalls, apply more force to the road, and wear out more quickly. Increasing pressure spreads the load out more evenly across the tread, as the air pressure becomes more significant than the sidewall support.
The only tyres where this doesn’t apply are the cheapest garbage on the market, any decent tyre will wear more evenly when over-inflated. I have found that tyres from 45 to 70 profile give the best wear life at 40 to 46psi.
Handling and braking: Honestly, there is no comparison. Good quality consumer radial tyres perform so much better with more pressure. Keep in mind that when you place a heavy demand on a tyre, you’re also transferring a higher proportion of the car’s weight onto it. More weight on the tyre means more pressure needed to spread the load evenly across the tread. Again, this is why radial ply tyres are so superior to cross-ply types. The wires support the high inflation pressure when lightly loaded, but allow it to maintain an even contact pressure as braking and cornering loads increase.
My first car was a ’78 Mazda 323, 1.3 litre RWD with tiny 145/70R13 tyres. These tyres gripped their best when inflated to 50psi. Steering feel was super precise and light, it had to be really pushed to break traction. I found this out by experimentation. Being young and a bit stupid, one of my favourite pastimes was chasing mates around mountain roads, and we’d all do whatever we could to gain some kind of advantage. Playing with tyre pressures cost nothing, so we experimented extensively and figured out exactly what worked.
Every car I’ve had since has followed the same pattern unless I’d cheaped out and shod it with garbage tyres. I should add that nothing can make cheap tyres work well, they don’t grip and they wear out quickly no matter what pressure you run. Don’t buy them, stick to the respected brands.
Rolling resistance and fuel economy: Anyone who tries to tell you that increasing tyre pressure can actually increase rolling resistance probably also believes the Earth is flat. Try riding a bicycle at various tyre pressures and tell me what you find out. Simple physics says that the harder a wheel is, the less rolling resistance it will have. There is no limit to this, the mechanism of rolling resistance is internal material friction due to distortion. There’s no magical pressure point where it starts to increase again.
Bottom line, more tyre pressure means better fuel economy.
Expert opinion: Go and do a defensive driving course. The first thing the instructors will ask you to do is pump up your tyres. They know, and by the time you’ve finished the course, so will you. You’ll probably never run your tyres at less than 40psi again unless you’re picking up frail Aunt Bessie for a quiet countryside drive.
Links to some articles regarding tyre pressure for defensive driving courses:
Understanding Tyres, Pressures and Grip
“Avoid tyre flex by increasing tyre pressures above the comfort-biased level suggested by the manufacturers. Firmer is safer in almost every respect, it will usually increase tyre life and improve fuel economy …”
High tyre pressure for defensive driving course?
“Higher pressures are used for such courses because she will be doing extreme exercises and the higher pressures mean better grip while minimising tyre wear.”
Do: Defensive driving course
“He says at 40psi you get maximum traction, shorter stopping distance, less likelihood of a rollover or a blowout, and optimum handling of the vehicle. It also helps to avoid aquaplaning. “
In answer to the question, an emphatic YES. Don’t be afraid to experiment with tyre pressure, but also don’t be disappointed if the increase in fuel economy is hardly noticeable. Just enjoy the fringe benefits you’ll get along the way, especially if you’re a somewhat spirited driver.