While I consider myself somewhat knowledgable about cars, here's something that just went over my head until yesterday:

After reading countless threads on "what's the best tire pressure" over the past two years, and having learned to ignore the manufacturer's sticker with the full-load tire pressures, I settled on a seemingly well agreed upon average of 31.5psi in Front and 38.5psi in Rear. I've been on that pressure for some time now, and it was loads better in the canyons. However, recently I've noticed some sliding and a "hard-tire" feel on sharp turns, which led me to check my pressures thinking maybe they needed more air (wrong diagnosis). I happen to come across a thread that mentioned hot-pressures on the track, so i thought I would check my pressures after a run up the canyons.

Luckily, my friend who tracks a Vette happened to be with me, and when he saw my hot pressures were 38F and 48R, he freaked out and said that was WAY too high. I have to claim total ignorance in the situation, as I just didn't know. He was in his GT3, so he checked his tires (a 997 running same Sport 4s) and his were only 35F 40R (and he drives harder in turns than me). The ambient temps were only about 80F too, and I've driven the same roads in the high 90s before, so who knows what the pressures were then.

So I dropped my pressure to match his, and wow, what a difference. I could immediately feel more bounce on the drive back (which I didn't like as much), but the car stuck in the hard turns with limited "hard tire feel", allowing a lot more push exiting the turns.

This morning in 61F ambient temps, the pressure reads: F: 29psi / R: 34psi. (Might try lowering a bit more as well)

So PSA, check your hot pressures if you do canyon runs!

 

Yep. And make sure your cold tires pressures are appropriate as well for street driving. Two different sets of pressures for two different purposes.

 

I feel like the consensus tire pressures are only a compromise because road cars don't have enough camber and have to work when cold. My track cars run around 30psi hot. That drops down to 20-22psi cold which is unsafe to drive home on.

Even putting around in the 996 I run lower pressures, 30F/36R cold with Advan V601, which becomes about 36/42 on the highway. This needs to drop significantly for the car to stick in turns.

 

Yeah, tire pressures can be tricky. It certainly is pretty easy to dial in pressures if you have years of track experience. You know what you are feeling in your butt, hands and feet. But if you don't, it takes some time to figure out how it all works. Same can be said with going thru different makes of tires like candy when you are tracking your car. All part of the fun.

 

Yes, I don’t want to learn hard way running 20psi on a grocery store run

Either I get tire blankets for the home, or find a compromise pressure that I can leave the house in, and not have to be the guy lowering his tire pressure half way up the canyon so he can drive faster then he already is, which is already too fast! (Not that I’m that guy, who is that guy, not me!)

 

If you want to make sure you car is ready to switch between canyon driving or street driving you may want to consider 3 things.

1. Get a decent digital tire gauge that is accurate, durable and quick to use. Below is a link to an affordable longacre gauge on amazon. I got a bunch of these for all my cars.

https://a.co/d/90N3Lvu

2. The second is to get metal valve stems to replace the rubber ones. They provide more durability on the track (canyon) as well as when you are constantly measuring your tire temps. The faster and more experienced you become, the more you check your tire pressures. Notice that I do not use a cap on the stem. Imho, they waste of time to screw on and off. This saves you a ton of time when you want to do a quick measurement.



3. Get the best damn tires with stiff sidewalls that can withstand tire pressure changes. As an example on the track, if you drop the tire pressures to 24 in the front when cold to get to 32 in the front when hot, it will take a couple of laps to get there. So you start out slower and build speed over a few laps to get to temp and inflation. Once you are at temp and inflation, you can use the tires properly at speed. But the tire has to be built for this with sufficient sidewall strength and compounds. Importantly, use the right tire sizes as well.

All Season tires and your run of the mill street tires are not built for this. Michelin Sport Cup 2s are street tires build for the track that can handle this. Bridgestone RE71RS are 200w track tires that you can use on the street.

But be CAREFULL to understand how the tires handle wet road conditions and colder temps, and most importantly, how long they take to heat up and get optimal traction. No need to wrap your 996 around a telephone pole.

Here is a picture of the Longacre gauge on Amazon if the above link doesn't work.

 

Price went up! I don't get this. Different model? Try this link :

 

I hear you on price.

I would stick with the Longacre for two simple reasons.

1. It's proven to be durable.
2. It's quick.

I would shy away from anything that you have to mechanically attach and then unattach. It kills time. Imho. It's worth a few more bucks for speed and ease.

 

duplicate post, sorry

 

I run low pressure around town in my 996.1, TW 60 Pirelli. 27F & 29 R cold pressure. Its like driving a magnet on steel roads... At hyway speeds I bring up pressure to 29&32. When doing long trips at very hi speeds 34&36 on my TW 200 or tw 300 tires

I do not like a long hose tire gauges at all. JMO.

The hose will take pressure to fill that can/will skew your 'real pressure. If using the long hose gauge all the time and bleeding out all the trapped hose pressure first, even after a little fumble on the valve stem, it will be ok. Try it, bleed the hose completely, then don't bleed the hose, then do a partial hose bleed,, see the difference in pressures... don't get me wrong, if used correctly its fine, just more a pia then needed for most regular car owners compared to my favorite idiot proof, below...

A Slime big display Elite Digital Tire gauge


But, hardly ever need a pressure gauge any more.
As I run a TPMS on all my cars trucks.
On my 996's a simple $30 screw on sensor, plug in to lighter socket, Amazon TPMS, works great for me. Is very accurate. Even measures heat of tire, good for you track guys. When a fill or bleed out in needed I use my Milwaukee tire fill tool with its own accurate gauge.
So been a while since I've needed to use a stand alone tire gauge in 2024...

 

I dont mind the hose. In fact i like it versus a shorter all in one. For me its easier to use and see quickly, but its always a personal preference.

I used the intercomp liquid gauges for over 20 years. Great gauges that have been dependable. But I had a heck of a time getting the RE71RS tire pressures just right. I needed more granularity. So I looked at the intercomp digital gauges and fell over with the prices. A bunch of the buys here on RL swear by the Longacre gauges so I took a look and found the digital gauge for a great price.

The digital gauge gave me the granularity to dial in the cold and warms pressures down to decimal points. The RE71RS seems to like 30/31 F and 31/32 R when hot for best performance with my set up.

Agreed, on the street, I run quite a bit less air in my Michelins. 36/44 is like driving on a thin strip with all of the new tires out in today's market. I typically shoot for 32/33/34 F and 34/35/36 for the street on street tires depending on the temps and weather.

But suspension set up has a huge influence.

Fun topic to discuss.

 

Just wait till I get on the actual track, then get to discuss it all over again ! haha

Will 100% be watching tire pressure like a hawk now till get comfortable how it feels. I wish I had thought of it sooner. Currently I pretty much only use the car to go up the canyon. So can leave the pressures lower, and just be careful on the drive up there.

I have a spare set of 997 Carrera Classic wheels that I think I will dedicate to track tires if it's worth running Pilot Sport 4s as street tires on the Solid Twists and getting something track only for the Classics

Feel i'm at the safe limit of the canyons. Probably overly past the sensible limit

 

Ben, what are the dimensions for the solid twist wheels and 997 Carrera wheels? What tires and sizes are you running on each?

 

Great thread. I
drive mostly on b roads, 2 lane and hills n twists, with other drivers, deer, cyclists, etc, very common. So I don't push often. I like the slow in, fast out blips that are so fun in a rear engine rear drive with just the right HP. To me then, I don't really feel much difference in a few psi.
Alignment is factory Street.
TIres are new last year, the Conti DWS 06 All seasons on 17s and in factory sizes. So 205 50 zr fr and 225 40 zr rear. These tires are forgiving and easy to drive on daily. The only downside to Conti is the annoying coating they apply that really makes it next to impossible to get a concours new look. Seriously, Google the issue of you are obsessed about detailing. For that reason alone, if you are considering performance all season, and want a nice clean tire, go Michelin. I chose Conti based on testing that showed they are quieter than the Michelin option. And much quieter than pirelli. But so dirty...
I keep an 'oak and iron' compressor in the frunk along with a brass 60psi Jaco gauge. I like the analog readout, what can I say. I use this tpms - Jansite 2023 Newest TPMS Tire... .
They look ungainly but I like the nerdy data. Next time I change tires I might add built-in tpms.
I find that with the factory psi settings from the door decal, the ride is just fine and the rear end is really predictable on power out of the corners. Very fun and confidence inspiring.
I just don't push heard enough to really experiment.
Maybe next that I'll make it to the DE event.
This year I'm just too busy. First I had that annoying electrical gremlin caused by my valved exhaust wiring (soldered connection was wonky). By the time I figured that out and had a reliable car, I had started restoring the house and painting it and roofing the garage etc etc. It's a big job. So the car comes second. I'm almost done painting the house. The highest bit still needs rotten siding and backing restoration, it's getting done this week. That stuff is way up there and the roof pitch is crazy on this old (1909) house. For this last peak / gable, there's no way to get a boom lift near, and there's no way to use staging, so long ladders and roof jacks are needed. Scary work, I'm getting help, thankfully.
I'm addition to the house and garage there are 19 windows and every storm sash needs repair, glazing, and paint, both black exterior and white interior. My sawhorse has been really busy. She's being ridden like.... Never mind.
Safe driving all!

Here you can see some rot and the basement exit, roof and door on the left. That prevents getting staging to access that highest peak.

A different angle. It should all be done this week. If you're interested let me know, I'll share some photos of the finished house. I got to it just in time. My mom has been living here alone in the family pile since the 90s, and as a son I neglected the maintenance. Salt air really kills the old paint. The new paint is ppg and is the best paint I've ever used. Its a magnitude better that what was used or even available the last time the house got painted. It still takes two coats. $$$$

 

Well that has got to be the most interesting segue...