My tpc shows around 44 psi on all four tires, but I was going to adjust them to what they should be. Should I use a gauge or use the tpc? My guess is the old owner had the tires changed and never adjusted the pressure. Most tire companies I've used simply make the pressure average on all four and never use the information in the door for tire pressure. The tire valve caps were all different and were the cheap kind so that was a clue.

From what I read, it should be 33/39.

thanks

 

Use a good quality manual gauge then use TPC to monitor relative pressures. Seldom will TPC = manual gauge readings.

 

Tire pressure is incredibly important to performance, safety, and the longevity of your tires. You should adjust your tires to the exactly correct tire pressure per the car/tire specifications. Set the pressure when they are cold (before you drive your car in the morning). Check the pressure with a guage every few days and compare it to your TPMS readings. If they stay in-line, than you can trust your TPMS and use it to see when you need to adjust the pressure. Keep in mind the pressure will increase as the tires warm up, so it is important to do these tests and inflation when the tires are cold. If you don't have a compressor, buy one. I have the Rolair JC10.

Ok, and I just have to address some comments in your post directly. Knowing that all four tires are set to the same pressure of 44 and also knowing that pressure is not correct is incredibly foolish. Also, most tire companies don't just average pressures. Tires and pressures are their jobs.

 

Nothing more reliable than an old fashioned analogue gauge.

 

i thought 37 Front and 44 Rear is recommended for 997.1..

i would use the gauge to fine-tune when u r filling / letting air out.. then rely on TPMS for constant monitoring. TPMS is pretty accurate IMO.

 

I think there is a fair amount of misinformation here. 44 lbs is on the door jamb, hence some ignorant tire shops may fill you to that level. The manual recommends 33/39, which I have used with good wear success. I've found TPMS inconsistent, I would not inflate your tires using it. Good for letting you know you've lost 10 lbs due to a leak, but that is it. I will concede that sometimes the pressure is correct, but not all the time!

 

My TPMS typically runs about 1 lb under what my manual gauge reads.

I'm pretty sure 44lbs is Max pressure. I run 33/37lbs cold on my MPSS and hot pressures can reach 44lbs on a spirited drive.

 

This is not correct. Pressure listed on the door or tire is ALWAYS cold pressure. If you are starting at 37 and hitting 44 when warm, your tires are underinflated (if 44 is the recommended pressure on the door/tire).

 

Had to take the car out yesterday to have the insurance inspection out and TPM told me I had a flat. So I pulled into a station filled her up and it then read correctly.

Then a few minutes into my drive TPM monitor came back on with an exclamation mark on the panel. I did notice one of the tires wasn't showing a reading is this why this might be happening? Monitoring the tire that said it was a flat as well to see if I have a slow leak or not. Before it did this checked the tires and readings on the 3 wheels that were showing looked good. Any ideas?

 

Since u have a 2007, it sounds like the batteries on the current TPMS sensor is low.

if it is, u will have to replace them with new ones (available at TireRack, i believe)

 

I've never looked at the door sticker actually. I run what was recommended to me by some good experienced friends who have similar driving styles and cars with the same tires. The car handles great, no roll onto the sidewall and very balanced grip.

Here's an interesting thread.

http://forums.rennlist.com/rennforum...pressures.html

 

ok didn't even know they had batteries will check this out thanks...

 

this is key

 

I check my tire pressure every two weeks. I go to a gas station late at night on fridays and overinflate them and saturday morning I bleed them down to the correct pressure. I use a longacre gauge. I like it a lot. They have lots of different models to suit everyone. I got the regular deluxe gauge with the ball chuck. If I could do it all over again, I probably would've paid the extra money for the digital gauge.

http://www.longacreracing.com/catalo...st.asp?catid=8

 

For a 997.1, the recommended pressure is 36/37 in the front and 44 on the rear wheels. These pressures are for the 19 inches wheels. They should be measured at cold temperatures (15-20 degrees Celsius).

In the USA, where derrieres are sensitive, a lot of people go with a lower pressure. It provides more comfort and allow to rub most of the small road imperfections and seams.

As a general rule, you should always follow the pressure recommended on the door sill, by the manufacturer.

I do not trust the TPMS and measure my tires with a couple of digital gauges.

Yves