Tire pressure etc
11-30-2011, 03:28 PM
#32
Race Director
what adias posted above is the sticker on the drivers door (i assume Euro models).
well the GTS along w/ other wide body cars wear 305s. The narrow body cars have 295s, except when using the Carrera sport wheels which have 305s.
Im guessing that this pattern will continue w/ the 991s.
What's exciting about the 991 is the use of wider front tires- 245s. I bet track guys will even go up to 255s.
well the GTS along w/ other wide body cars wear 305s. The narrow body cars have 295s, except when using the Carrera sport wheels which have 305s.
Im guessing that this pattern will continue w/ the 991s.
What's exciting about the 991 is the use of wider front tires- 245s. I bet track guys will even go up to 255s.
11-30-2011, 07:49 PM
#33
Three Wheelin'
Thread Starter
Jay H
If you would re-tire the car in 19's, I'd suggest a high performance all season such as the new Bridgestone Potenza RE970 AS Pole Position or the Continental ExtremeContact DWS tires. I've driven the Conti's in anger (on a different non Porsche vehicle) and they are a great all season tire that really hangs on in aggressive street driving, but offer a quiet ride and a very nice ride quality. I have the previous generation Potenza RE960 on my '84 911 and I simply love those tires. The 970 has newer technology, but a very similar tread pattern to the outgoing RE960's.
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This is the kind of info I was looking for...THANKS...
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I may just try one of the above and if I like the ride, sell off the almost new Conti's.
If you would re-tire the car in 19's, I'd suggest a high performance all season such as the new Bridgestone Potenza RE970 AS Pole Position or the Continental ExtremeContact DWS tires. I've driven the Conti's in anger (on a different non Porsche vehicle) and they are a great all season tire that really hangs on in aggressive street driving, but offer a quiet ride and a very nice ride quality. I have the previous generation Potenza RE960 on my '84 911 and I simply love those tires. The 970 has newer technology, but a very similar tread pattern to the outgoing RE960's.
***********************
This is the kind of info I was looking for...THANKS...
***********************
I may just try one of the above and if I like the ride, sell off the almost new Conti's.
Last edited by dak911; 11-30-2011 at 07:51 PM. Reason: Copied wrong paragaph...oops
11-30-2011, 07:53 PM
#34
I sympathize with your situation since I view ride quality greatly as well. I moved from a Base Boxster (987) with 17" Continentals to this 997 and the ride quality change has been quite noticeable between models both with base suspensions and base wheel and tire combos.
11-30-2011, 08:20 PM
#35
Rennlist Member
11-30-2011, 08:21 PM
#36
12-01-2011, 07:26 AM
#37
Tire-pressure can be calculated
Tire-pressure is all about load on the tire, and for this forum also speed and alignment is important.
The Y tires here may have a maximum speed of 300 km/h But above 220 km/h a system of higher pressure is working, Above 270km/h even the printed maximum load goes down ( at 300km/h it looses 15%).
Then if the camber angle is above 2 the pressure also has to be higher.
But it is not adviced for high speed to have a camber-angle of above 2.
I once got hold of the European formula, that the tire-makers use to determine the advice-pressures like on that plate shown here, and worked it out.
Translated a few spreadsheets I made to English to spread it over the world.
Placed them on my skydrive of hotmail adress with the same username as here ( combine my Email adress yourselves, spamm robots cant).
https://skydrive.live.com/?cid=a526e...E092E6DC%21235
This link leads to a map with spreadsheets and examples for re-calculating for other then original tires, but can also be used to check the originals.
To use a spreadsheet, click on the I in a circle at the end of the line, then in the right barr at Download, and after download open it in Excell or compatible.
Then you will be surprised how low you can go sometimes .
But these tires with low aspect ratio ( 30% and 35%) you have to be carefull with. I suspect the calculation of the maximum load to be on the high side.
So dont go to low or calculate with a higher pressure then the reference pressure of 2.5 bar/36psi for normal car tires ( American tires 2.4/35).
From the link I gave, you can navigate my complete public map of skydrive, like in a forum. More then half is about tire-pressure, with even my own formula.
Succes, and if you cant work it out , give me the details , and I will do it for you.
Greatings from Holland
Peter
The Y tires here may have a maximum speed of 300 km/h But above 220 km/h a system of higher pressure is working, Above 270km/h even the printed maximum load goes down ( at 300km/h it looses 15%).
Then if the camber angle is above 2 the pressure also has to be higher.
But it is not adviced for high speed to have a camber-angle of above 2.
I once got hold of the European formula, that the tire-makers use to determine the advice-pressures like on that plate shown here, and worked it out.
Translated a few spreadsheets I made to English to spread it over the world.
Placed them on my skydrive of hotmail adress with the same username as here ( combine my Email adress yourselves, spamm robots cant).
https://skydrive.live.com/?cid=a526e...E092E6DC%21235
This link leads to a map with spreadsheets and examples for re-calculating for other then original tires, but can also be used to check the originals.
To use a spreadsheet, click on the I in a circle at the end of the line, then in the right barr at Download, and after download open it in Excell or compatible.
Then you will be surprised how low you can go sometimes .
But these tires with low aspect ratio ( 30% and 35%) you have to be carefull with. I suspect the calculation of the maximum load to be on the high side.
So dont go to low or calculate with a higher pressure then the reference pressure of 2.5 bar/36psi for normal car tires ( American tires 2.4/35).
From the link I gave, you can navigate my complete public map of skydrive, like in a forum. More then half is about tire-pressure, with even my own formula.
Succes, and if you cant work it out , give me the details , and I will do it for you.
Greatings from Holland
Peter
12-01-2011, 03:49 PM
#38
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On the road, I'm just as happy because they manage to retain that steering feel despite filtering out the harshness that other high-performance tires pass through. Cindy is happier with these tires than any of the previous ones this car has worn.
They aren't N-rated yet, but since the ones I bought are approved by Ferrari, Maserati, Aston, and Lamborghini, I consider the delay bureaucratic. At most, it's a question of Zuffenhausen working out the pressure recommendations. Maybe I should offer to send them our worksheets, or at least the final result...
Somewhere around here is the report I posted of that test day, but the bottom line is what I've said above.
Gary
12-01-2011, 03:57 PM
#39
Rennlist Member
They're an excellent tire, Alex. I spent a track day doing nothing but assessing them and doing the temp/pressure measurements to arrive at a set of pressures that distribute the heat properly. They exhibit all the traits I want in a track tire: high grip, a wide 'plateau' in a drift, stability under braking, and excellent steering feedback. They just feel right.
On the road, I'm just as happy because they manage to retain that steering feel despite filtering out the harshness that other high-performance tires pass through. Cindy is happier with these tires than any of the previous ones this car has worn.
They aren't N-rated yet, but since the ones I bought are approved by Ferrari, Maserati, Aston, and Lamborghini, I consider the delay bureaucratic. At most, it's a question of Zuffenhausen working out the pressure recommendations. Maybe I should offer to send them our worksheets, or at least the final result...
Somewhere around here is the report I posted of that test day, but the bottom line is what I've said above.
Gary
On the road, I'm just as happy because they manage to retain that steering feel despite filtering out the harshness that other high-performance tires pass through. Cindy is happier with these tires than any of the previous ones this car has worn.
They aren't N-rated yet, but since the ones I bought are approved by Ferrari, Maserati, Aston, and Lamborghini, I consider the delay bureaucratic. At most, it's a question of Zuffenhausen working out the pressure recommendations. Maybe I should offer to send them our worksheets, or at least the final result...
Somewhere around here is the report I posted of that test day, but the bottom line is what I've said above.
Gary
If you sent your worksheet to Zuffenhausen, don't forget to ask for a FAT consulting fee!
12-02-2011, 01:46 PM
#41
i second the michelin pilot super sport recommendation....i have noticed a quieter ride, tires are more supple and ride smoother, incredible grip and performance, and great in the rain...
06-03-2019, 10:24 PM
#42
AutoX
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Accuracy of Porsche Tire Pressure Info ondash Display?
Has anyone compared the dash tire pressure read out with actual tire pressures? Are they accurate enough to let pressure out using that as a guide?
Much easier to check air pressure with the dash display while on the road.
Much easier to check air pressure with the dash display while on the road.
06-03-2019, 11:44 PM
#43
Rennlist Member
Mine is off by about 2 lbs in my 997.1
06-03-2019, 11:46 PM
#44
Nordschleife Master
On the 997.2 the dash TPMS readings are accurate.
06-04-2019, 03:58 PM
#45
Drifting
I use an exceptionally nice liquid filled pressure gauge to fill my tires. Even so, when I mount them, the dash readout on my 997.2 usually has at least one of them showing a pound or two off when cold. The difference is just enough to drive my OCD brain crazy.