Tire Pressure

[ace123]

I have an 87 911 with Pirelli PZero Nero tires on them. The "max pressure" says 53, but how much should I put in there?

I'm just cruizing around town, not racing or anything. I push the car around the corners every now and then.

Also, is there any relation to tire pressure and noise in the cabin.

Thanks!

[John W.]

I run 29 in front 36 in rear. My guess would be lower pressure / softer tire would be quieter.

[86 911 Targa]

Originally Posted by ace123

I have an 87 911 with Pirelli PZero Nero tires on them. The "max pressure" says 53, but how much should I put in there?

I'm just cruizing around town, not racing or anything. I push the car around the corners every now and then.

Also, is there any relation to tire pressure and noise in the cabin.

Thanks!

We have the very same configuration on 7" and 8".

I run 29F & 36R.

A good compromise for ride comfort & wear.

Although, the PZero Nero have a very high (numerical) wear index.

Good luck,

Gerry

[ace123]

Thanks il give it a try. 29. 36. Sounds good!

[HawgRyder]

I always went with the old method.
Roll the tire (wheel on car) onto a dollar bill placed in front of the tire so that about 1/2" of the bill is captured by the tire.
Inflate tire until you can move the bill....then deflate about 5 pounds (the bill should be grabbed again).
Take a pressure reading....record it...this should be your best pressure for THAT tire.
Not all wheels will be the same (on my car I have 4 different pressures because I have a friend sit in the car as I do it...he weighs the same as me).
This should give you maximun contact with the road...but not have underinflated tires.
You can also (after a few thousand miles) see the wear pattern of the tires...bare in the middle=too much pressure....bare on the outside edges=too little pressure.
Bob

[dshepp806]

Recco'd tire pressures located on inner door tag....it's 29F and 36R for me, too.

Doyle

[ace123]

Interesting. Old school is a good idea. I didnt know about the door panel. I have more wear in the middle of the tires. I guess I should take some air out.

[Jerome74911S]

29 in front and 34 rear, not 36, is most often recommended. Tire noise may be affected by pressure, but tread design is a bigger factor.

[86 911 Targa]

Originally Posted by ace123

Interesting. Old school is a good idea. I didnt know about the door panel. I have more wear in the middle of the tires. I guess I should take some air out.

Center tire wear, due to the rear engine configuration, is an issue that has, over the years, plagued many 911 owners.

After 30 years of 911 ownership, the 29/36 with regular monitoring, has served us best.

Also, when checking tire pressures, I always add an extra 3-5 lbs, let the car sit overnight, then remove the excess as driving the car just a few miles can add 3-5 lbs in tire pressures.

Good luck,

Gerry

[dshepp806]

Yeap,..those recco's are COLD pressures. As stated , on my '89, her door reads 29/36,..I consider THIS the "reference" (to adjust "from")......

Aside, I keep 2-3 gauges (types) around to make sure I'm not trusting an erroneous gauge,..just to doublecheck the gauge every-so-often.

Best,

Doyle

[RWebb]

if you guys will change to 32/34 you will get a LOT better handling

P AG did things to the later cars to dial in more understeer over the years, as their customer base became less competent, and were no longer "drivers of a special breed"

[Nine17]

After a lot of playing around (I have a compressor, retractable air hose, and racer's gauge), I've found with my current set of Kumho Ecsta SPT's (205/16 and 225/16 on 7's and 8's) that 36/40 is my sweet-spot. Modern tires seem to like a bit higher pressures than were recommended when our cars were new.

[80-911SC]

I agree with Nine17 the newer tires make a difference .. my Kuhmo Ecsta Le Sports like about 35f/38r ... I drop them a bit for AX but only when they get hot and raise themselves ...

Steve

[PatrickB]

Originally Posted by RWebb

if you guys will change to 32/34 you will get a LOT better handling

P AG did things to the later cars to dial in more understeer over the years, as their customer base became less competent, and were no longer "drivers of a special breed"

I run 32/33 HOT.

[Quicksilver]

The earlier cars had 29/34 on the doors and the heavier, later ones have 29/36.

As far as what tire pressure to run...
Currently I run 24 front and 31 rear cold pressures for dry grip. That works out to give me a well balanced car with maximum grip. What does that tell you? Not a whole bunch unless you have the same tire in the same sizes with the same t-bars on the car and abuse the car to the same level.

Start with what's on the door and that gives a starting point. If you are serious about wringing out the car you will need to start experimenting. With a conventional treaded street tire your maximum grip will usually be at higher pressures (often much higher). With minimal tread and/or 'gumball' R compound tires the max grip will generally be with lower pressures. Adjust the pressure on one end of the car so you can see what the changes do to the balance of the car. Start on the end of the car with the least grip and adjust till you see what direction to go.