Tire Pressure - "spirited" Daily Driving
05-24-2015, 05:34 PM
#1
Tire Pressure - "spirited" Daily Driving
Hi Guys
Michelin Pilot Sport Cup 2's MPSC2
After some searching couldn't find a best answer - What would you recommend for everyday "spirited driving" (non track). Keep in mind that I don't want excessive wear.
My car arrived with tires set to 31.5 Front and 35 rear (cold). Hot they get up to around 34 and 38. I found that at "higher speeds" the car felt less planted than I would expect (loose) at these pressures and hence this post.
Car plate recommends Cold 29 / 33 (front / rear) for road use.
Michelin recommends Cold 24 / 26 (front rear) and Hot 33 / 36 for track and per manufacturer spec for road use.
Lots of discussion on https://rennlist.com/forums/991-gt3/...ith-mpsc2.html about lower Hot track tire pressure (29 / 31) providing better grip but with likely higher wear.
So is the manufacturer right this time - is Cold 29 / 33 best for every day use ?
Should mention I'm in the north east and average ambient temperatures don't get much higher than 72-86 °F (22 -30 °C). Spring and fall = less. So it seems like a best "HOT" pressure is most relevant given locational temperature variation and the simple fact that we spend most of our time driving a "Hot" tire.
Cheers
Michelin Pilot Sport Cup 2's MPSC2
After some searching couldn't find a best answer - What would you recommend for everyday "spirited driving" (non track). Keep in mind that I don't want excessive wear.
My car arrived with tires set to 31.5 Front and 35 rear (cold). Hot they get up to around 34 and 38. I found that at "higher speeds" the car felt less planted than I would expect (loose) at these pressures and hence this post.
Car plate recommends Cold 29 / 33 (front / rear) for road use.
Michelin recommends Cold 24 / 26 (front rear) and Hot 33 / 36 for track and per manufacturer spec for road use.
Lots of discussion on https://rennlist.com/forums/991-gt3/...ith-mpsc2.html about lower Hot track tire pressure (29 / 31) providing better grip but with likely higher wear.
So is the manufacturer right this time - is Cold 29 / 33 best for every day use ?
Should mention I'm in the north east and average ambient temperatures don't get much higher than 72-86 °F (22 -30 °C). Spring and fall = less. So it seems like a best "HOT" pressure is most relevant given locational temperature variation and the simple fact that we spend most of our time driving a "Hot" tire.
Cheers
Last edited by 2016RS; 05-24-2015 at 08:14 PM.
05-24-2015, 06:15 PM
#3
I think the 29/33 is about right, they end up very close to the track recs at about 32/36 driving in 50 to 70 degree weather.
I was told going 38+ on these tires is a bad idea, too high and they'll become like driving on ice. Not tested it myself, but this was from the head tech at one of the local motorsports shops.
I was told going 38+ on these tires is a bad idea, too high and they'll become like driving on ice. Not tested it myself, but this was from the head tech at one of the local motorsports shops.
05-24-2015, 09:05 PM
#4
Burning Brakes
I was at 28/32 cold for the Smokies run. Hot temps were 33/36. Ambient temp was from mid 70s to low 80s depending on elevation and time of the day. Car handled great!
05-24-2015, 10:20 PM
#5
Rennlist Member
Hi Guys
Michelin Pilot Sport Cup 2's MPSC2
After some searching couldn't find a best answer - What would you recommend for everyday "spirited driving" (non track). Keep in mind that I don't want excessive wear.
My car arrived with tires set to 31.5 Front and 35 rear (cold). Hot they get up to around 34 and 38. I found that at "higher speeds" the car felt less planted than I would expect (loose) at these pressures and hence this post.
Car plate recommends Cold 29 / 33 (front / rear) for road use.
Michelin recommends Cold 24 / 26 (front rear) and Hot 33 / 36 for track and per manufacturer spec for road use.
Lots of discussion on https://rennlist.com/forums/991-gt3/...ith-mpsc2.html about lower Hot track tire pressure (29 / 31) providing better grip but with likely higher wear.
So is the manufacturer right this time - is Cold 29 / 33 best for every day use ?
Should mention I'm in the north east and average ambient temperatures don't get much higher than 72-86 °F (22 -30 °C). Spring and fall = less. So it seems like a best "HOT" pressure is most relevant given locational temperature variation and the simple fact that we spend most of our time driving a "Hot" tire.
Cheers
Michelin Pilot Sport Cup 2's MPSC2
After some searching couldn't find a best answer - What would you recommend for everyday "spirited driving" (non track). Keep in mind that I don't want excessive wear.
My car arrived with tires set to 31.5 Front and 35 rear (cold). Hot they get up to around 34 and 38. I found that at "higher speeds" the car felt less planted than I would expect (loose) at these pressures and hence this post.
Car plate recommends Cold 29 / 33 (front / rear) for road use.
Michelin recommends Cold 24 / 26 (front rear) and Hot 33 / 36 for track and per manufacturer spec for road use.
Lots of discussion on https://rennlist.com/forums/991-gt3/...ith-mpsc2.html about lower Hot track tire pressure (29 / 31) providing better grip but with likely higher wear.
So is the manufacturer right this time - is Cold 29 / 33 best for every day use ?
Should mention I'm in the north east and average ambient temperatures don't get much higher than 72-86 °F (22 -30 °C). Spring and fall = less. So it seems like a best "HOT" pressure is most relevant given locational temperature variation and the simple fact that we spend most of our time driving a "Hot" tire.
Cheers
Although many stateside have found 28/31 to be an idea hot temp for the MPSC2 on the 991 GT3 at the track I have found that the car operates very well at closer to the manufacturers recommended 33/36 on the track. This may be affected by the camber you run (mine is -2.0 F/R so closer to stock), ambient temp and track surface structure. I have found the tyres work really well for me at around 32 front and 35 rear. Others experience may differ. They differently get a bit greasy once the rears go above 38. I have taken to going out at around 26/29 first session out on a dry track. After 6 laps I find its sitting close to optimal, although it can get up a little high by lap 8. You can then adjust off in 1psi increments between sessions...
The key I have found is never to drop the pressures below 26 cold before the first session as otherwise the TMPS keeps chiming a warning (it is programmed to do this at below 26 psi. You can use the Race Mode on TMPS to adjust beyond this but that can be a bit fiddly...
For the road I have found generally speaking the recommended 29/33 at 20C is fine. Once up to temp you will see 33/37 when pushing on on twisty roads. For prolonged hard road use (canyon runs etc) I have found its good to start around 28/31 and youll see 33/36 when pushing on...
05-26-2015, 08:59 PM
#6
Tried running 29 / 33 Cold (31 / 36 Hot) - Much better at speed.
Might try dropping the rear 29 / 31 Cold (31 / 34 Hot).
Hopefully the wear will still be reasonable at these lower pressures.
Cheers
Might try dropping the rear 29 / 31 Cold (31 / 34 Hot).
Hopefully the wear will still be reasonable at these lower pressures.
Cheers
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05-27-2015, 04:45 AM
#8
Racer
Join Date: Feb 2014
Location: edmonton, alberta, canada
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never paid much attention to what pressures mine were at till the other day i was scrolling through the menus and found mine were at 44 and 48!
i know this was hot as id been driving for a few hours but i knew this still had to be too high. i never adjusted the tire pressures in any way before so i wonder why they would have set the pressures so high in my car.
i immediately got out and let out 5-6 psi from each tire. the next day after i started the car they were showing exactly 29/33. i guess i let out exactly the right amount. oddly i didnt notice any difference in ride quality before or after.
i know this was hot as id been driving for a few hours but i knew this still had to be too high. i never adjusted the tire pressures in any way before so i wonder why they would have set the pressures so high in my car.
i immediately got out and let out 5-6 psi from each tire. the next day after i started the car they were showing exactly 29/33. i guess i let out exactly the right amount. oddly i didnt notice any difference in ride quality before or after.
05-27-2015, 09:19 AM
#9
never paid much attention to what pressures mine were at till the other day i was scrolling through the menus and found mine were at 44 and 48!
i know this was hot as id been driving for a few hours but i knew this still had to be too high. i never adjusted the tire pressures in any way before so i wonder why they would have set the pressures so high in my car.
i immediately got out and let out 5-6 psi from each tire. the next day after i started the car they were showing exactly 29/33. i guess i let out exactly the right amount. oddly i didnt notice any difference in ride quality before or after.
i know this was hot as id been driving for a few hours but i knew this still had to be too high. i never adjusted the tire pressures in any way before so i wonder why they would have set the pressures so high in my car.
i immediately got out and let out 5-6 psi from each tire. the next day after i started the car they were showing exactly 29/33. i guess i let out exactly the right amount. oddly i didnt notice any difference in ride quality before or after.