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TPMS showing low pressure..so I bought a NEW gauge and adjusted the pressures 30 front 38 rear, 18" wheels on a 2007 BASE
THIS WAS WITH WARM TIRES....ambient temperature 87, 5 mile low speed drive. (I figured a few pounds more for the heat)
Monitors show 42 on one rear 40 on the other, 35 on one front 33 on the other...(the sensors were checked in December when the new Michelins were installed)
What would be the absolute best most accurate gauge to buy?
How much more to add for warm tires?
 

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How much more to add for warm tires
Cold tire pressure is measured at 68 Degrees F. Tire pressure changes 1.5psi for every 18 Degrees F change in tire temp-Right out of the Porsche owners manual.

I like this Longacre because of the large easy-to-read face, the log, flexible hose and it holds the reading after you remove it from the valve. The 2% accuracy is reasonable which is about 1/2 lb at 30psi.

Longacre Tire Gauge
 

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What would be the absolute best most accurate gauge to buy?
I got to agree with the other guys. Your not sending a rocket to the moon. Its air on a street car. Any reasonably priced gauge will do. And I agree with getting an oil filled, large faced Longacre Racing gauge. Easy to see, Oil filled. It just works.
 

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Given your earlier sentence in your reply (it's not rocket science), is $80 your idea of a reasonably priced tire gauge?

Since it's not rocket science and it is a tire gauge on a street car after all, $80 seems like a lot of scratch to spend on a tire gauge when there are many capable ones available for under $20.


Eddie

...Any reasonably priced gauge will do...
 

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Given your earlier sentence in your reply (it's not rocket science), is $80 your idea of a reasonably priced tire gauge?
Yes, that's cheap for a quality product that should last the next 20 - 30 years. I found this Longacre Racing oil filled gauge Amazon.com: Longacre Liquid Filled Deluxe Tire Gauge 0-60 psi: Automotive $53, nice big gauge, oil filled. For $50 your getting near gold standard product here. The power tank 8200 is $70 and would be probably be fine too. OTH, if you buy some cheap digital thing, it will get high Amazon ratings because, well its cheap. What are you going to do when the battery dies, its the winter, the cold kills it, and you have no spare? Will you be still using it 20 years from now or will it be obsolete next month? In the long run, a $50- $80 analog product from a reputable racing establishment is cheap and reasonably priced.

The OP asked what the "absolute best accurate" gauge. I don't know. But I do know that for the street I don't need this $400 Longacre Temp Compensated Tire Gauge 53050 accurate to 0.1 lb. when this for $53 will last me 20 years Longacre Liquid Filled Tire Pressure Gauge 52002

So to accurately answer the OP's question, he could buy the $400 Longacre and be accurate to 0.1 lbs. BTW, I also bought the Porsche OEM gauge in 2006 and it still works.
 

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Good points chow4us and thanks for the additional info.

I was at RRV in the Pit and when the 919 came in and I saw the Porsche pit crew carrying when I thought were tire gauges (and using them immediately) but they looked nothing like the gauge I use. Turns out they looked a lot like the ones you mentioned and not my $10 Accutire Digital Special. :hilarious:

So I guess the OP needs to get the Longacre $400 special if he wants the "absolute best accurate" gauge. I wonder if the OP is going to drop 4 BF's to get that level of accuracy?


Eddie


Yes, that's cheap for a quality product that should last the next 20 - 30 years. I found this Longacre Racing oil filled gauge Amazon.com: Longacre Liquid Filled Deluxe Tire Gauge 0-60 psi: Automotive $53, nice big gauge, oil filled. For $50 your getting near gold standard product here. The power tank 8200 is $70 and would be probably be fine too. OTH, if you buy some cheap digital thing, it will get high Amazon ratings because, well its cheap. What are you going to do when the battery dies, its the winter, the cold kills it, and you have no spare? Will you be still using it 20 years from now or will it be obsolete next month? In the long run, a $50- $80 analog product from a reputable racing establishment is cheap and reasonably priced.

The OP asked what the "absolute best accurate" gauge. I don't know. But I do know that for the street I don't need this $400 Longacre Temp Compensated Tire Gauge 53050 accurate to 0.1 lb. when this for $53 will last me 20 years Longacre Liquid Filled Tire Pressure Gauge 52002

So to accurately answer the OP's question, he could buy the $400 Longacre and be accurate to 0.1 lbs. BTW, I also bought the Porsche OEM gauge in 2006 and it still works.
 

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Thanks guys, what I should have said is the "most best" REASONABLE gauge, all things considered....so I guess my $19.95 gauge is OK!
 

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TPMS showing low pressure..so I bought a NEW gauge and adjusted the pressures 30 front 38 rear, 18" wheels on a 2007 BASE
THIS WAS WITH WARM TIRES....ambient temperature 87, 5 mile low speed drive. (I figured a few pounds more for the heat)
Monitors show 42 on one rear 40 on the other, 35 on one front 33 on the other...(the sensors were checked in December when the new Michelins were installed)
What would be the absolute best most accurate gauge to buy?
How much more to add for warm tires?
I use 31 or 32 front COLD; 36 rear COLD. 30 front with warm tires isn't enough. Steering will feel better at 31 or 32 COLD in front.

I don't think accuracy to the nearest .01 psi is the point. You need a consistent gage that will be fairly accurate. You can set the tires at the pressures on the label on your door...or look in the MANUAL. Remember the manual?

If you drive and feel the tires are too sloppy, put a pound or two more in them. I found the rear tires really pound on the pavement if they have more than 36 cold (on my gage). Found 32 works pretty well for the front, but a little less is sometimes a little softer riding without hurting the handling much. 30 feels too soft. 30 warm would feel positively mushy to me.

Summer tires with stiff walls start riding harder if they're under-inflated. They start riding more on the hard sidewalls. You want the sweet spot above that somewhere before they get too much pressure and are too hard and unable to absorb bumps. The suspension works best there...at least for me. Cold pressure is supposed to give you a nice minimum working pressure so that most normal driving will not take them out of their sweet spot.

As to how much the pressure should be with the tires warm...How warm?

The time to measure pressure is in the morning before you've moved the car or just out in the driveway. OK to move it 10 feet. Best way is with it at the ambient temp it will be driving in, but if you can't do that, you can adjust

by adding or removing a bit less than 1 pound per 10 degrees difference between where the car is while checking and actual ambient out where it will be driving.

That means, in a heated garage, you'd add extra air to the normal cold pressure. If it's summer and your garage is cool, subtract air when cold-inflating.

I use a little digital plastic gage shaped like a trigger handle that I bought from a vendor at a race track somewhere. It's called Accugage, I think. The name has worn off the thing because it's been in my pocket a lot. Black trigger handle and it's fairly flat and fits in a pants pocket easily and gives a reading quickly. It's great for pulling in to hot pits and making quick adjustments for HOT pressure.

I just pull it out, take a quick reading and, usually, let air out. I do the hottest tires first because they'll lose temp the fastest. Then back in and GO. That Accugage is supposed to be accurate to half a pound. I couldn't swear it's true, but it's the one I use all the time, so I've adjusted my personal hot pressures to the readings that work on this gage. I think it's a pretty good gage.

The other one I use is a digital gage I bought from from a bicycle store. It's a little fatter and looks more like a normal tire gage. I keep it in the garage. It takes a little longer because it goes though a little boot-up thing where it zeros at ambient pressure before it gives the "0.0" and is ready to use. It's got a button to go from PSI to Bar to whatever that other pressure measurement is....the metric one. You get a little beep when it's ready. Then put it on the tire and it will hold the highest pressure for 10 seconds or so. If you're adding air, you can add quickly and re-measure. Subtracting requires a new boot-up procedure.

I don't really like the extra booting, but it's a very accurate gage. The best part of it is that it doesn't let much air leak out when you take a reading because it seals nicely around the valve stem. That's nice for smaller tires...like bikes and motorcycles and low profile tires that change pressure easily with just a little bit of are added or removed.

Hope this is helpful in some way. These digital bike gages are in most good bike stores.

:cheers:
 

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Thanks guys, what I should have said is the "most best" REASONABLE gauge, all things considered....so I guess my $19.95 gauge is OK!
:eek: This is a Porsche forum. $60 isn't reasonable for a fine tool you can use long after your car is in the junkyard? ;)

Be glad you didn't ask this in the 991 Turbo forum or the Ferrari forums :hilarious:
 

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I have several of the Longacre oil filled gauges around (because racing) and they all read the same as each other, read the same as my tpms, and have those adorbs glow in the dark faces. Plus they're durable. Well worth the $70 or so, and we've been through a lot of gauges.
 

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+1 Longacre. When it comes to gauges, you get what you pay for. As the saying goes, "I don't make enough money to buy cheap things" certainly applies in this case. For the twice a year mechanic, Craftsman wrenches are awesome vs buying Snap-On. But gauges are different, especially for a high performance car. You (or I) don't need a $400 pressure gauge, but don't waste your $25 dollars and buy the $60-70 Longacre.
 

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I have both types of gauges in my cars, and honestly I prefer digital now. If you pick a good one, with good reviews on amazon - it's a breathe to use, accurate, backlit display, small/easy to store in the car, and batteries last forever. I think mine is two year old and no need to change batteries.
 

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