Tire Pressure

[Mr.Incognito]

Anyone know what pressure my 225/45/17 kuhmo supra 712's should be at on a 99 camry 4 cyl?

[Naito]

check your door jamb

[Naito]

no it doesn't matter that ur tires are aftermarket and differnt from your stock ones....check you door jamb! (should be written there...if not check ur owners manual)

[rayray]

actually, i think the recommended tire pressure is on the side of the tire itself.. in PSI (pounds per square inch).



the owners manual will show the recommended pressure for the stock tires not aftermarket ones. usually, the lower the profile the higher the pressure.

-rayray

_________________
1992 Camry LE 5S-FE
Calgary

<font size=-1>[ This Message was edited by: rayray on 2002-07-12 17:17 ]</font>

[Naito]

no, that's a common mistake....the number on the side of the tire is the MAXIMUM pressure the tire can handle....filling it to that will give you uneven tire wear (the centre of the tread will wear out first) and it's quite dangerous...ALWAYS follow the door jamb number...

[EKam]

On 2002-07-13 00:22, Naito wrote:
no, that's a common mistake....the number on the side of the tire is the MAXIMUM pressure the tire can handle....filling it to that will give you uneven tire wear (the centre of the tread will wear out first) and it's quite dangerous...

And that answer is correct.

ALWAYS follow the door jamb number...

But that doesn't apply to tires that's not the same size as stock.

[Xenon]

I always thought tire pressure was tire pressure. No matter what tire you have on what profile you always have to follow the number of psi's specified for the vehicle..

[rayray]

On 2002-07-13 00:32, elegantcam wrote:
But that doesn't apply to tires that's not the same size as stock.

so exactly what is the guideline for tires that are bigger than stock?

-rayray

[Xenon]

I didn't understand the question!! But I probably don't know the answer to it anyways..

[bondobondo]

this is a hugely debated subject, from ppl saying that the door jam number is artifically low to start with, because they rate the pressure for a tire that is going hiway bound for its entire life and they use that rating.

now when a tire is on the hiway, it is HOT, very hot, and the vehicle manufactures have to use a safety of margin in that air expands when it is hot, so they have to estimate a safe operable pressure. they have ratings like 28-31psi usually.

now if you drive in the city most of the time, your tire will never reach such a hot temperature, so a high psi rating can be used, around 31-34psi

if you are at teh track the tire is much hotter than what it would normally be, hence an even lower pressure than stock to compensate for the high temperature: 24-27 psi

vehicle manufactures also calculate load bearing on each wheeel and they have to ensure that there is suffecient psi in the tire to carry these loads, for a passenger car they are usually at the maximum, of 1 driver and 3 passengers.

no matter what profile tire, a &quot;safe&quot; operating pressure would be around 30-33psi, 35 at the highest. as any higher would make the center bead of the tread wear out prematurely, and usually at the higher pressure, the tire runns cooler, performs better (in the dry definately, in the wet, it is marginal) provides better feedback to the driver, and corners sharper.

[EKam]

On 2002-07-13 10:29, trueno92 wrote:
if you are at teh track the tire is much hotter than what it would normally be, hence an even lower pressure than stock to compensate for the high temperature: 24-27 psi

I hope you're kidding, cuz last time at auto-x I had to pump it up to 41 psi and everybody increase their tire pressure, not lowering it.

[EKam]

On 2002-07-13 02:09, rayray wrote:

so exactly what is the guideline for tires that are bigger than stock?

-rayray

Simple, you follow the tire manufacturer's recommended tire pressure for the specific size! :grin:

[bondobondo]

On 2002-07-13 10:49, elegantcam wrote:

I hope you're kidding, cuz last time at auto-x I had to pump it up to 41 psi and everybody increase their tire pressure, not lowering it.

at an autocross it is different, cuz you get 1 run, yes, ONE RUN.

and then your tires cool for like 30 mins until your next run.

if you drive decent, that run lasts for under 1 minute.

if you go to a lapping event, or something where your tires are ALWAYS turning, and you are going at speeds alot higher than 60km/h in 2nd gear, your tires DON&quot;T get a chance to cool, even in the pits for 20 mins won't cool them down.

you are cornering at higher speeds, braking at higher speeds, these are all sever demands placed on a tire.

compared to taht 1 minute of fame on an autocross, a decent car can lap around for a good 10-15 mins, until brakes/engine have to cool.

so no, i am NOT kidding.


_________________
æ92.FF.pilot

<font size=-1>[ This Message was edited by: trueno92 on 2002-07-13 13:51 ]</font>

[boroEF]

On 2002-07-12 17:15, rayray wrote:
actually, i think the recommended tire pressure is on the side of the tire itself.. in PSI (pounds per square inch).



the owners manual will show the recommended pressure for the stock tires not aftermarket ones. usually, the lower the profile the higher the pressure.

-rayray

_________________
1992 Camry LE 5S-FE
Calgary

<font size=-1>[ This Message was edited by: rayray on 2002-07-12 17:17 ]</font>

u do that if u want to blow up ur tires

[TRD 4Runner]

For off roading...drop the pressure to 7 psi :grin:

The tires on the 4Runner can handle 44psi...filling it up to that made it feel like driving a bus on stilts.