kilted

That's the sticker I was talking about, it lists the gross vehicle weight and that siort of stuff, but the spots for the tire pressures are blank.

G8rboy

What about the driver door then? I know it's on one of them... just can't remember which...

kilted

Not on my car, no PSI's listed anywhere on the car

G8rboy

Odd... maybe mine was a one-off. I've got two stickers, one on each of the driver's side doors, one has the pressures printed on it, the other one doesn't.

galleychief

Look at the sidewall of the tire it will give recommended pressure range and a maximum psi recommendation.

G8rboy

Problem is each vehicle has a recommended PSI that the tire mfr's don't know about... you won't find 32psi anywhere on the tires... and the maximum pressure is way too high to run (something in the mid 40's I think).

rx8cited

The recommended tire pressure is also in the 2004 Owner's Manual on page 10-7 if that helps.
I forget if it's the front or rear drivers' side door sticker on my car that has the pressure listed.

Also, I highly recommend getting an accurate digital tire pressure guage that you can trust.

StewC625

Mine doesn't have the pressures listed either - mine is a Sept 2003 build. I just referred to the owner's manual and then wrote a big 32 on that label with a Sharpie!

zoom44

There Is A Pressure Guage On The Pump In The Tire Inflation Kit In The Trunk.

G8rboy

I second that- I was suprised how badly out of calibration my old analog one had gotten when I tested it with my digital (got free from Tire Rack a while back).

G8rboy

Isn't it in Kilopascals or some other goofy metric measurement? :D

RX8 Pusher

OK, here is my 2 cents…..reading this post gives me (from most, but not all) the indicator that owners are relying on the TPMS to let them know when they need air in their tires…..while yes, it will indicate when the tire pressure drops to a certain threshold, here is some food for thought.

Proper tire inflation is paramount to optimal tire performance, especially in high performance situations.

Tires (in general, not necessarily our low profile high performance tires) can lose up to half of their air pressure and still not appear flat. You should check your tire pressure at least every 30 days.

Always check tire pressure when tires are cold (idle for at least three hours). Now most of us do not have an air pump at home and have to drive to a gas station to get air. So, if you need three pounds at home, and drive to the gas station make sure you use the original feedback you received from a cold tire. Do not get there and check again, notice that now you only need 2 pounds and go with that.

One poster, who was replying to where you can find the proper tire pressure recommended for the RX8, suggested the tires sidewall. Simply not true , the information provided there is for the maximum tire inflation/pressure, and not the proper inflation/pressure for our specific car.

One must remember that the cars engineers take a lot into consideration when they come up with the recommended tire pressure for any particular car. The priority of these considerations varies based on the type of vehicle: Safety, Ride, Fuel Economy, Performance to name just a few. It is recommended to take the tire inflation/pressure for a given vehicle and raise it 2 to 4 ponds. In our case: recommended 32 psi + 2 to 4 psi would be 34/36 psi for our vehicles. There are a number of reasons for this but the overall factor is simple: You get less performance out of a 4 pound under inflated tire than you do with a tire with 4 pounds over the recommend pressure. (Yes, I know that one can and does fine tune adjustments (1 pound at a time) to maximize the tire/suspension/car reaction to certain driving surface/temperature/conditions and this is not my point)

Under inflated tires have softer sidewalls that will reduce the contact patch of a tire (I drive 4X4 as well, so do not get the sand/snow techniques for reducing tire pressure confuse you here) by allow the sidewall to bulge out, and cupping the contact patch. (Look at the attached picture). Not only are you loosing contact patch surface area but you will suffer from a softer sidewall, which allows for greater lateral movement (leaning) of the sidewall. Of course this is a really bad thing, as under inflation is the number one reason for a tire blowing out/rolling off of the rim.

I suggest, since we have a car that requires you to check the oil level often that you check the tire pressure (cold tires) then as well.

MEGAREDS

I should drop by the forum more often... my tire light went off yesterday -- with the associated bell sound at start up which I had never heard before -- and I misdiagnosed the problem as a brake issue (the symbols are somewhat similar). The local dealership adjusted the pressure and off I went, feeling pretty dumb.

The interesting thing is that I ran winter wheels without TPS all last winter, and I never heard that warning bell before. Am I right in assuming that when there is no TPS signal, the light just blinks, and there is no bell?

Silver04RX8

I had the TPMS light come on yesterday morning on the drive to work, it went off on the way home in the evening, so I thought it might be a fluke since it was in the 30s. This morning same thing happened again. I went and checked the pressure, all 4 were definitely under 32 and one was at 26, inflated them all to 32 and the light is gone. Take the advice, trust your TPMS light and check those tires.

typerr

I just bought my 2004 RX8 last week. The morning after I took her home I got the TPMS light and I'm in SoCal where it really does not get very cold. The damn dealer let me leave the lot with 27psi in all 4 tires

valpac

iTrader: (2)

kPa IS the goofy metric measurement. And the gauge is probably more accurate than those dime store presure gauges you get everywhere. I just used my tire inflator to add air to my tires (nice to have air on hand). 220 kPa is the proper cold pressure (Owners manual pg. 10-7 or sticker on drivers door below latch)

Gyro

A picture I took this morning that goes nicely with the topic.



Winter is here in New England.

Hespra

First time for the tire pressure light this morning. It went off about 4 miles into the drive. I stopped at Shucks on the way home and bought a digital pressure reader. Cost $13. Don't know if it is a "good" one or not. Was the only digital they had---and the last one of those on the rack. Now waiting for car to sit 3 hours to take a "cold" reading.

If I understood what I read, one adds however many pounds the cold test reading indicates and does not then follow whatever "warm" reading when one arrives at the gas station with air pump. Am I interpreting correctly? Thanks
H

Katchoo

It may actually come on when less than 29 PSI which is where mine pops on. I have a slow leak in one wheel/tire assembly and the dealer can't find it so I am quite familiar at what PSI mine will pop on.

Yours may be a bit different...there are no absolutes in mass-produced items.

Katchoo

Heck...mine let me leave the lot with 45 PSI cold in all 4 tires when I bought the car. It was like driving on a skateboard. I checked the PSI when I got home (the TPI light was on the whole way but it was 11PM and I wasn't stopping in THAT area ) and the pressure warm was 54 PSI...scary!

Hespra

I assumed dealer put car in apple-pie order before it left the lot on Sept 5-04. Perhaps that was the case. Didn't think about tire pressure until light went on this a.m. After work, I bought a digital guage and read the pressure this p.m. after car sat for an hour. Didn't have time to wait 3 hours for cold reading. So...lukewarm: one rear tire 24, one at 26 and the other two at 27 psi. I stopped at gas station on my way to appointment and brought all four tires to 32.

Read in the tires section of this forum that 34/36 psi optimal. Will check them tomorrow when cold. Now seems unlikely the tires were properly filled when car left the lot.

rx8cited

Absolutely?, but I've never seen my TPMS light come on since I've owned it (13.7k miles), so I don't have any personal data to give you.

You may wish to direct your to your local Mazda service department regarding your car's TPMS sensor(s) being absolutely out of spec according to this:
http://www.finishlineperformance.com...02-004-04.html

That's assuming you're using an accurate pressure guage and you read the cold tire pressure vs taking your reading after driving to the point that it warmed up to 29 PSI.

How many minutes/miles does it take after you start the car and drive it before the light comes on when in this low pressure condition?

L8APEX

Hello all,

I am new here, glad to find this forum.

My question is this? My light comes on, and I check the tires when cold, and they are all at 32, cause I am obsessed with checking them, seeing as how there is no spare. Is anyone else having this problem, where the light comes on even with the correect pressure. Do I have a faulty sensor? My dealer here in Atlanta has not had one person mention this issue.

rx8cited

1) Are you sure your tire pressure guage is accurate?
2) Are you checking the tires when they are cold?

If yes to both, then it seems that you have one or more bad TPMS sensors.

scottmhr1

Hey, you have to pay $0.25 for air around here. My light came on today, severe tempt drop today. I refuse to pay that much for air for $1000.00 tires! Seriously the pressure was just a hair low, but a good reminder. Will adjust them again now that it is time to quite driving it here, Getting close to SALT time on the roads