Same on my Shinka, I had to look in the manual.

 

It's really easy to fix this problem nino. Just stick your pressure checker on the tire, and allow some air to leak out. Let go - take a measurement, and repeat.

Last time i was in Austin, my friend was going on a spirited drive. He was told before the drive that he should inflate his tires to something like 50psi before the drive, to help protect the tires or something. This seemed suspect to me, and even dangerous especially as on a spirited drive the tire pressure would go even higher. He thought so too. What tire pressure do you guys use if you're going on the track? If you're heading out for a run on the twisties?

 

Majority opinion I've noted at the track says shoot for about 40 PSI while hot. At VIR in June, that meant (for my setup/tires) I set them to 34 PSI when cold, since they increased about 6 PSI when they warmed up. This differs in each situation. Last fall at Summit Point / Shenandoah, my tires increased about 10 PSI when they warmed up, partially since Shenandoah is a much tighter track.

Setting them to 50 PSI cold before a spirited drive sounds way too high, IMO.

 

32 PSI in all 4 when cold, end of story.

The car rides way too stiff when you have the tire pressures @ 40+. Last autocross I didn't deflate the tires after my runs and they were around 40 psi hot all around, the car felt like I was riding a horse on the drive home.

 

Low tire pressures on "spirited drives" can lead to the tires rolling off the rims under hard cornering. I've seen it happen on tracks. Most track tires I've seen are run at relatively high pressure both for this reason and to stiffen up the sidewall (stiff sidewall = more responsive tire). While it is true that lower pressure will increase your contact patch, if the tire is all sloppy that is usually much worse.

The "cold pressure" on the side of the tire is usually a max for cold tires. The tire pressure will increase as the tire warms up, and it going beyond this value is okay when the tire is warm. Just don't exceed it when cold.

Manufacturers and dealers are in tune with their customers when setting tire pressure. Lower pressures (~30 psi) make a more supple ride, but also less responsive. This appeals to 99% of the drivers in this world. If you are in the 1%, then the "dealer recommendations" may not be right for you. You should be able to safely run cold tire pressure anywhere between the dealer recommended value and the max pressure on the side of the tire.

 

If your pressure is too high, you will see excess wear in the center tread blocks. Short of that, it is whatever feels comfortable, within the range mentioned above.

In my daily driving, I am only getting a 3 degree rise, even on hot days (Hot for Maine is 85 btw), so I have been using 35psi as a cold pressure. Very little loss of ride quality with much crisper steering response and better feedback.

 

I'll run the tires at 40 for a long trip to save on gas, but cruse at 32

 

I am used to seeing recommended pressures up to 10 psi below the max. But the Bridgstone Potenza's max. is 51 psi and the recommended pressure is only 32. That seems like a ridiculously high difference. Is anyone out there familiar with a standard practice of running tires so far below the max?

 

Mine were the same way when I bought the car new. Came from the dealer this way! I don't know if they increase the pressures for transport or what.

 

I thought that at first too and then I realized that there are two stickers. One is on the front door and one is on the back door but only one of them has the tire pressures on it.

 

You are not supposed to drive with your pressures at the maximum tire pressure. This is just a rating for the tire. You will find best grip and stability is between 35-45 psi. This is a large range of pressure, but the best pressure for performance depends on the tire type, ambient temperature and how hard you are cornering. Street driving will not warm the tire very much, but a track day will really cause your pressure to increase while lapping and you don't want to exceed 45psi when hot.

 

Sometimes a tire installer will inflate a tire to a very high pressure to seat the bead. I'm not sure if that's proper practice or not (don't think so, but I've never mounted car tires), but if they do it they're supposed to drop it back to the right pressure.

Some years ago I bought a set of tires for my Accord, and when I got home I found they were up around 40 psi - rather than either the "normal" 26 psi or "max load" 32 psi. That was at a Goodyear store - one that was soon converted to a "Just Tires".

Ken

 

Good point ken-x8,
I always pick up my car with 42 psi too, and it is probably becuase of the reasons you mention. On the other hand, tires should bead at a certain pressure (about 40-45psi I think). If they do not bead at that pressure, then you should not keep increasing the pressure until they do, something is wrong.

I'd rather pickup my car with too much pressure and leak it out... than have to pump them up again becuase they only put 32 psi in them...

 

Sorry to wake up this old thread, but I just got my car back from the dealer. On the way in for service, on the first chilly morning of September, my TPMS light was on, and it went off once I got the tires warmed up. Along with everything I needed them to do, I asked them to please fill the tires.

They filled them to 38 PSI cold.

I told the service guy I thought that 32 was the recommendation, and he assured me that Mazda recommends 38. I was in a hurry, but when I got home, I checked the sticker and the book... 32 PSI.

Now, here's the thing... I like the way the car rides at the higher pressure much better. The TPMS, which according to the manual is supposed to detect pressure too high, is not lit. I had tire noise at 32 PSI which doesn't seem to be there at 38.

So... is my dealer just plain wrong? Did Mazda change the recommendation due to tire noise complaints? I have a 2004 with the stock Bridgestones - is there a different recommended pressure for the Dunlops? Any input would be helpful.

 

I'm certain Mazda didn't change the recommended tire pressure, which is 32psi, as you say. But here's a thought… maybe Mazda unofficially recommends that dealers overinflate the tires to 38psi to compensate for dramatic seasonal or day/night temperature differences. In other words, yesterday it reached 80şF here in NYC. But just 3 weeks from now it might get down to 30ş one night in nearby Danbury, CT—which means, checking tire pressures monthly, I'll now add an extra 5 lbs (one pound for each 10ş drop in temperature) to compensate for the coming cold. Maybe that's why he said Mazda "recommends" the higher pressure. (Just a guess.)

 

No idea what Mazda recommends, or if they even make recommendations for pressure. The dealers may know that, based on your location, a higher pressure is best.

I run mine ~40.