How so?? That doesn't make sense.

i know right... i thought like that too thats why i pump a bit more.. but my fuel consumption dipped .. usually i can get about 420 to 450 km per tank but if i pump more air it drops to about 400 km per tank.. tested it over the past year using michelin xm2 tyres .. how about your experience?

Pump 1 more psi should not make much noticeable difference but it also should not make the FC worse. I suspect is more about the driving style or the tires. You need to measure correctly also to really draw a conclusion.

can share your experience with different psi settings and your tyres?

See tire pressures actually also will steadily/slowly go down bit by bit. So for example when I pump 35psi on my car, after maybe 3 weeks or so, the pressures will already drop to around 32psi, sometime more, sometime less. The FC when I was on 32-33psi seems to still be about the same as when I was using 34-35psi, or at least not significant enough of a difference to conclude. However I think my best FC record was achieved when my tires were at 34-35psi. Note that I measure my FC practically every full tank, meaning every time I refill full then divide by distance traveled, so it's real average FC and not based on econometer estimates.

Actually is OK if u drive fast or carry full load 5pax
On my camry the sticker say u can put 210kpa for light load & <160 kmh speed
Increase to 290kpa if for 5pax full load &/or >160kmh speed

So saying if u know ur Gonna ferry five pax then u go inflate the tyre just for this particular journey? After that deflate it again? Or just keep it at 290

Nice info from Camry!
I learned from internet saying for highway travelling (km/hr not specified), increase OEM pressure by 10%.
So I started off upping 10%, now in 30% territory ....
Would appreciate very much if you could upload a picture of said sticker... for general guidance ..... if it isn't too cumbersome for you.

Just keep it there. What pressure that you need to maintain is depending on your most frequent driving condition, don;t need to be so impractical and keep changing back & forth. For example myself, since I often reach highway speeds so then I maintain about 3 psi above std recommended pressure. As I explain also above that this is a precaution/margin too so that if the pressure drops, it will still be around the recommended pressure. In short, use the pressure that suits your driving the most and maintain that. However note that over inflating a bit above the recommended is safer than under inflating as under inflating tends to build up surface heat faster and therefore higher risk of blow out.

Took a shot of the Camry manual instead.
Generally if you drive at higher speed ranges/carry more load you need to adjust tyre pressures accordingly.

Also note these are cold tyre pressures, interestingly some cars (Merc) they specify to add (up to) 4psi for warm tyres, guess that depends on how hard/long you were driving otw to the air pump.

This post has been edited by ceo684: Feb 11 2017, 04:15 PM


Attached thumbnail(s)

Thanks heaps, mate.
Learning something new and authoritative on tyre pressures from your posts .....
I read some tyre literature saying that after parking between 30 min to an hour, one may pump air at indicated OEM cold tyre pressure.
Your attachments are rather detail and specific...
Btw, can I have your prior permission to upload your above pictures in forums like Bitog/lowyat etc for the benefits of others in times to come ?

This post has been edited by zeng: Feb 11 2017, 11:35 PM

Ok noted 👌🏻

Tire size does matter on this , bigger profile means carry more load and overall load .

Based my experience using stock tyre Turanza ER370 (recommended 33 PSI front & 32 PSI rear). All good.

Once change to Ecopia EP200, 33 & 32 PSI somehow increase my fuel consumption, noisy & tyre feel like less air.

Pump up to 35 & 34 PSI. All optimized. They said EP200 compound is softer than average tyre.

For me recommended tyre pressure stated on door side or manual is for stock tyre. Good to follow.

But if change to different tyre brand / model, the optimum air pressure will be different.

not a tyre expert here but then softer compound usually is stickier rite

about the recommended tyre pressure stated on the side of the door is a general guide for the car, as manufacturer have tuned the whole suspension to work best with that kind of pressure. of course it varies by tyre if you decided to stick on a high performance tyre compare with eco tyre that manufacturer are using.

the number there is for mass user who will be opting for similar tyre size and range

Am I the only one who look at pascal unit? I can't seems to brain psi indeed.

I would add another 5% or less of air pressure due to the OEM instruction is based on cold tyre. By the time you get to gas station you will have hot tyre.

This post has been edited by therain01: Jun 28 2017, 01:57 AM

is the recommended psi is based on cold tyre if itz not stated on the sticker?
if so, when we inflate warm tyre, how much psi should we add?

Think so.

My benchmark is fuel consumption. Noise level & comfortness are subjective for me. Based on car insulation too.

By right, eco tyre should use less fuel than non eco tyre.

by right eco tires should use less fuel than non eco tires as the rolling resistance is way lower thus reduced the need for more power to push the car move.

but then if pair with eco tires and yet your golden right leg still stomp the fuel pedal like normal then is still going to be same

in addition, to achieve better FC with eco tires is actually let the car glide more.

This post has been edited by herojack41: Jun 29 2017, 04:42 PM

A tad clarification on the bold phrase pls. Do you mean the exact tyre the car came with when it went out the car dealership,
or do you mean that the manual states the tyre pressure for tyres of the same range/size?

My understanding will be OEM tyre. Tyre originally fitted in upon purchasing the car.

I don't think same pressure applicable with tyre with same range / size. Unless exact same brand, size & model.

Eventhough same range / size, different tyre manufacturer or even different model will be using different compound, soft / hard sidewall, etc. That contribute to optimum tyre pressure.

Not so expert lah. Based on my experience & reading only.