diesmile

Hi, i have 16 IS200t F sports with 18inch tyres (front width 225mm profile 40 and rear width 255mm, profile 35)

according to the sticker on the side door, the pressure should be around 37, but dealer pumped it up over 40 PSI, what do you guys put in?

i am asking this question is because yesterday my wife just had her RX270 serviced, the report came back saying all her 4 tyres are about 3.5mm left, this is really bad for only 20k travel she did in 2 years. the service department told her they pump over 40PSI into them while the other time, they said a much lower number, could under inflated tyres causes this issue?

thanks.

Rebirthing

"Tires"

I put 36 front / 38 rear.(Cold)
40 cold is way too much

diesmile

thanks, and i am from Australia

CarlitoIS

Well from where he is from the word tyre is exactly the word tire to us. Haha.

Anyways, the dealer always pumps it to 40 PSI.. Not sure why. I think 38 PSI is just about right. That's where I tend to always leave it at.

peteharvey

The tire pressure used all depends on how often you check your tires, and whether you prioritize handling, comfort, or tire longevity.

If you are willing to check every fortnight or monthly, and you prioritize comfort, then you can use the recommended pressure sticker on the driver's door.

On the otherhand, if your priority is maximum handling, and you tend to throw the car around a bit, or you prefer to be lazy and just check the tire pressures once every 3 or 4 months, or one becomes rather upset at having to replace tires after just 20,000 miles, then best that you inflate at say 10% above the recommended air pressures eg 40 PSI etc.

The number one reason why dealers tend to use 10% over-inflation is because many people check their tire pressures every quarter, or even less often!

PS Also make sure you check tire pressures early in the morning before driving off, because later on in the day, and esp after a 15 minute drive, the tire pressures rise due to heat from running...

diesmile

thanks, i won't mind if it lasted 20k miles, but it is only 20k kms.

peteharvey

If tires are wearing out prematurely, check:
1) make and model of tires used,
2) check tire pressures monthly, or fortnightly if one is that precise,
3) check wheel alignments annually, and rotate tires annually, and
4) and ultimately, please pay attention to how fast your wife drives; how fast she accelerates, brakes and corners, and how much high speed driving she does, because hard cornering for example, will cause premature outside edge tire wear, especially on cars like the RX with a high center of gravity, long suspension travel, compliant coils and sway bars, simple single lower link MacPherson strut suspension, and baggy SUV tires, which cannot keep the outside wheels perpendicular to the road surface on hard cornering due to body roll.

Under-inflation would probably be the biggest single cause of premature tire wear...






.

Rebirthing

Oops, my bad! Apologies...