TPM ? for Steve

[awdjdmtalon]

Steve.

What is the threshold for setting a TPM on the 04 G's. I had my tires set at 35psi front and 32psi rear.

This morning it was 41 deg. when I left for work, and the TPM set. I checked the pressure at lunch. 33psi Front and 31 psi Rear.

Is 31psi low enought to set the light? Or am I looking at a TPM that may have a battery going dead?

ThanksJerry

[awdjdmtalon]

ok i have let the car sit in the shop for an hour to let the tires cool and pressures equalize. F 34psi R 31.5 psi.

[C-Kwik]

I wanna say its 28 psi.

[joe603]

+1 on 28psi

[awdjdmtalon]

it is 28. I found it in my owners manual. Tire pressure was 31 at the lowest when i checked it. May have been lower when I frist drove off this morning.

Reset pressures. Now need to drive it to reset the light.

[RED_DET]

I would recommend running 38-40psi cold tire pressure. There will be less than 5% difference in hot tire pressure and will allow the tires to last longer. Just food for thought.

[awdjdmtalon]

I would recommend running 38-40psi cold tire pressure. There will be less than 5% difference in hot tire pressure and will allow the tires to last longer. Just food for thought.

I am running the tires 3psi lower to try and curb the issue of wearing the center of the tread out before the outer edges.

[SteveTheTech]

+1 for 28 lol a little too late

It will also set a code if its over ~40something. It is not a pressure code it sets some random communication code. I start adjusting tire pressure to 35 in September to try to keep as many tire lights off as I can.

Jerry,

I can imagine the original air pressure in your tires was <28 this morning it was cold here and the wifes tire looked really low too, by the time I got to the shop they were 33. Are you running the Michelins in the rear? If you are I understand trying to curb the center tread bar wear. I would try taking your tire gauge home and checking the tires before you leave for work to see what your cold soak tire pressure is. Then just adding that much later.

Its amazing what crazy things are inside that owners manual.

[awdjdmtalon]

Thanks Steve.

I am going to put a tire gauge in the car, so I can check the pressure in the am, if the light comes back on.

I am running Nitto NT 555's on the car now. The Michelins were almost bald on the rear at 20K, and the fronts were feathered so bad I thought I had a wheel bearing going bad.

I guess the original owner never had the alignment checked. But it is good now. Set it when the new tires went on.

Yea the owners manual has a lot of good stuff in it. It is funny. I ***** all the time about the owners not reading the manual for their cars, when they bring them in for stupid stuff. And here I did the same thing. LOL

[RED_DET]

I am running the tires 3psi lower to try and curb the issue of wearing the center of the tread out before the outer edges.

Be careful of running them too low, because you will get the opposite effect and wear out the edges because the tires will be cupped in the center. This can be a serious issue if a panic stop was necessary. Under heavy front braking, if there isn't enough air in the tires, they will cup and only the outer edges will contact the pavement. The center should wear some what more than the edges unless you have alignment issues. You contact patch is the center of the tire.

For those hesitant on running the tire pressures I recommended, conduct the tests for yourself. Start out with recommended tire pressure of 33 psi cold. Drive the car around for a few minutes until the tires get warm. Check the hot tire pressure and it should be within 5% of the cold. If its not, let the tires cool off and start over with a higher cold psi and then check hot psi. Somewhere around 38psi cold, the tires will only heat up 2psi to get to hot temperature. Running too low of tire pressures also effect hydro-plane temperatures. The lower the psi, the lower the speed when you begin to hydro-plane. A 5 psi difference equates to about 3-5 mph difference in when hydro-planing will take effect.

Under inflated tires also effects MPG and steering response.

This information wasn't just made up, it was learned in accident reconstruction course.

Those low tire pressure recommendations are only in place to benefit the tire company, because "heat" wears out tires more than anything else. So constant significant change in tire temperature of cold to hot is a bad thing, which is why you want to limit the amount of change.

There are also some numbers on the side wall of your tires that you should be concerned with: Look for the (DOT) section and read the numbers. A number like 3408, means that tire was manufactured in the 34th week of 2008. So just because you buy new tires, doesn't mean they are really new, so keep that in mind next time you go to purchase them. It isn't recommended to run tires that are 3yrs or older.

[awdjdmtalon]

Thank you for the Info RED. Check out the Tire experiment that I am doing. It is stuck at the top of the threads.

I do have a fair bit of experience w/ tires. On top of being an Auto Tech for the last 7 yrs. I also raced SCCA autocross for 5 yrs. I know all about he affects of heat on tires. Esp. when it comes to inflation and grip.

I was an E stock regional champ one year and runner up another. The only real perfomance upgrade you can do in stock class is tires. And they must be a DOT R compound.

I was also runner up in D Street Prepaired another year.

I also Drag race import AWD. I did that for the last 4 yrs.

[SteveTheTech]

Thank you for the Info RED. Check out the Tire experiment that I am doing. It is stuck at the top of the threads.

I do have a fair bit of experience w/ tires. On top of being an Auto Tech for the last 7 yrs. I also raced SCCA autocross for 5 yrs. I know all about he affects of heat on tires. Esp. when it comes to inflation and grip.

I was an E stock regional champ one year and runner up another. The only real perfomance upgrade you can do in stock class is tires. And they must be a DOT R compound.

I was also runner up in D Street Prepaired another year.

I also Drag race import AWD. I did that for the last 4 yrs.

Wow, impressive sounds like fun.

I guess that explains the screename.

[Focusedintntions]

I guess that may explain why my light came on....i have my rear tires set at 42 psi when hot.....tire max is 55....i'll try letting a few psi out and see if it resets

[Sentientbydesign]

There's a dealership misconception that only the Michellins have the poor inner bar wear issue.

My RE050As were worn in that pattern from the previous owner. I haven't monitored the current pair, because they are crap tires (bought for drifting and haven't swapped them yet), but the next pair will be monitored closely.

[SteveTheTech]

If they are over inflated the light will usually flash. That either signifies that or a communication issue., both related codes.

[awdjdmtalon]

I think most people fail to realize that over inflation wears the middle of the tire. Where under inflation wears the outer edges.

And I don't think that the 18" wheels are too narrow for the 245's. Every tire manuf. that I have checked, recommend a 7.5-9" wheel for the 245 tire.

[SteveTheTech]

Even when they are properly inflated the Michelins still wear in the center. The 245s do fit perfectly on it. I just think their tire selection sucks.

[C-Kwik]

The interesting thing to think about is that both the 350Z and G35's (except for models using the same 18's from previous years) moved up to 8.5 inch wide wheels in 06 while keeping the same tire width. I haven't heard much complaint about these...

[awdjdmtalon]

It does seem that the wheel is a bit on the narrow side for the 245, by what the tire manf. reccomend, but still w/in the range. And they also went to a different tire brand/ type when they move to the 8.5 wheel. So we are back at square one of speculation. The whole chicken or the egg question.

[C-Kwik]

It does seem that the wheel is a bit on the narrow side for the 245, by what the tire manf. reccomend, but still w/in the range. And they also went to a different tire brand/ type when they move to the 8.5 wheel. So we are back at square one of speculation. The whole chicken or the egg question.

Absolutely. But I've run a different tire with the same results. There is some anecdotal evidence that the tire tread may be bowing out on an 8 inch wheel. I would imagine a tire with stiffer belts may be less susceptible to this effect, but a manufacturer may be less apt to use such a tire due to the extra weight and expense such a tire may cause, so long as performance is still good/acceptable. It wouldn't make good sense for a manufacture to specify 2 different wheel widths if both can fit the desired tires safely, unless there was some further benefit to be realized. But then this is merely speculation on my part...

[awdjdmtalon]

Absolutely. But I've run a different tire with the same results. There is some anecdotal evidence that the tire tread may be bowing out on an 8 inch wheel.

From what you have said, leads me to think that the tire is then over inflated. Infiniti may have had the tires set to a higher pressure to make the center of the tire taller. This way making less rubber on the road to help with rolling resistance to help fuel economy.

Over inflation wears the center of the ties out. Under inflation wears out the outer edges.

This all rolls back to my tire pressure test that I am conducting.

[C-Kwik]

From what you have said, leads me to think that the tire is then over inflated. Infiniti may have had the tires set to a higher pressure to make the center of the tire taller. This way making less rubber on the road to help with rolling resistance to help fuel economy.

Over inflation wears the center of the ties out. Under inflation wears out the outer edges.

This all rolls back to my tire pressure test that I am conducting.

Problem I find with that statement is that with a tire to wheel match that is not pulling/pushing the sidewall in/out, the tread will likely be fairly flat under load at typical tire pressures. Its not like Infiniti is recommending higher than typical pressures used in other passenger cars.

You do bring up an interesting point about rolling resistance though. But my question might be, did they choose this tire size such that it might cause a slight bulge in the center tread to serve a similar purpose? I'm sure they've done a lot of testing with different tire sizes, pressures and wheel widths. Perhaps this choice had the best balance of traits they wanted. Especially when you throw the cost into the mix. I doubt tire life was a big part of that equation, considering it becomes the consumer's expense once it's off the dealer lot...

[TISon28s]

The light goaway after about 10 minutes of driving. Since it's cold outside, you should always put your pressure up about 2-3psi from what it's supposed to be. The light usually comes on when your pressure it 20% down.