Hi all; longtime lurker, newly registered. Question on tires and their safety. I have a 2006 C2s with OEM Pirelli P0 Rosso's all around-- extreme summer performance tires. I understand that these tires are dangerous on snow and ice and should NOT be driven thusly-- but I have not been able to determine how safe they would be on just cold pavement-- on a clear and dry road. I live in Phoenix so no need for all season tires or any concern there, but I have a cabin in the mountains (nice twisty, turns, no cops-- heaven in the summer!!) and was thinking of visiting it and driving the Black Hole (my name for the pcar). Would I be safe in like 40+ degree F temperatures or would the tires still be dangerously greasey and I would doing something more stupid than I usually do? Can't seem to dig up any info on this-- even from tire manufacturers sites (probably the old liability thing going on..) Any observations and advice would be greatly appreciated!

 

From what I've heard, below 45 deg F summer perf tires lose their grip pretty rapidly. I've noticed same in my 911 on dry pavement. I wouldn't go nuts in these temps. Normal to "sporty" might be ok, but any more aggressive you could be asking for trouble.

 

Around 40 degrees, if the tires are cold, be careful with turns, until they heat up a little.
I skidded around a turn unexpectedly, with P Zeros, several years ago, just leaving an address on the way home at 40 degrees or so.

 

I wouldn't regularly drive the car on stock high performance summer tires. I've done it several times however in the Boston area, once I drove to work in November at about 35 degrees. The tires felt brittle and it was a little loose in the rear. More recently, I drove from Boston to Maryland in January, with snow on the ground, so I could drop off my car for a Turbo mod at TPC Racing in Maryland. I kept the car at low to moderate speeds and had no problems. I was taking some chances in both cases, but for occasional use, you can probably get away with it. If you want to drive your car regularly in the colder weather, invest in a set of winter tires.

 

Above 40F, with care.

 

I have driven on my Michelin Pilot Sports when the roads are clear of ice and snow, but there is a loss of performance. I also have Pirelli Corsas which I will not drive on until it warms up.

 

Since compounds vary between manufacturers, this is the important point. We live in the Mojave Desert of California, and we lived in Tempe years ago. Like you, I don't even bother with all-season tires.

A few seasons ago, we had one of our rare snowfalls here. A proper blizzard, with fairly warm temps but only by comparison to the Midwest. In the low twenties, I'd say. but I needed to travel so we took our NSX with Michelin Pilot Sports. No problem at all. Had I been foolish enough to try full power starts or high cornering rates, we would have given the traction control some work to do, but since I did not, nothing.

A few weeks ago, we had those heavy rains here that preceded the snow blanketing the East Coast. It was the first chance to find limits for the 997.2 we'd just bought, so when traffic died down in the evening, around nine or so, I took it out by myself making runs around a section without homes. (I mean the formal sense of 'section' for city folk. One square mile on a side.) Temps were mid thirties to very low forties, as I remember. Rain still falling, and standing water on the roads. Seemed a perfect time to try the car at the limits, which surely had been brought down far enough to explore them in those conditions.

Zip. Nada. The PS2's held on like a Summer day. Mind you, I worked up gradually to higher g loads, and I also have this thing about pushing any car without corner workers and paramedics and other niceties we enjoy on the track. So I was nowhere near track loads. But I was well above speeds I would drive on public roads if there were even a home within earshot.

Bottom line, it wouldn't bother me to take this car up to Tehachapi or even Big Bear with these tires. But back to the original point: What is true for the PS2 compound, may not be true for your tires. Tip toe on those Pirellis until you have a sense of how the compound behaves in low temps.

Gary

 

Around 44.5 degrees F is when summer compound tires begin to loose their effectiveness.

You'll find that this number holds true with most tire manufacturers (all the tires I sell use this as a reference). Not to say they can't be used in cooler temperatures, just that they become similar to the consistency of hockey pucks.

Places like bridges and areas that are shaded most of the day will pose a problem while driving because of the inconsistency in road temperature and therefore traction.

Suggesting that you invest $1000+ in winter tires would be foolish but be careful how you drive in cooler climates and remember that just because the ambiant temperature is above 45 doesn't mean that the road surface is sticky.

 

I was quite lazy to change my PS2 set to PA2 set and I can tell more or less precisely - at 28 degrees PS2 totally transforms into glass. When I moderately pressed on accelerator leaving gas station my rear completely lost traction and went sideways. It felt very wrong. PA2 on same temperature were rock solid. At 32 - 34 degrees I also felt some lost traction, but it was was not yet like riding on glass. At 28 degrees it was non-drivable.

 

I noticed the RE 050A's got very loose below 45 deg. That was also before the tires were warmed up. The main tricky thing about the stock 911 is that it understeers initially into corners. I turned into a corner and wow did that thing plow. I would certainly not recommend driving them into the mountains. You will have a sense of security getting there - they will perform great getting there because the tires will be nice and warm. BUT when you start up after a break and head home, you have the easy potential to wreck if you do any turns at even moderate speed.

 

Thanks, guys, for all your advice and observations. I may or may not go up there-- the trip starts out in Phoenix at about 1,500 feet elevation and a temperature of 65-75 degrees-- runs up I17 (at 75-80 mph so that should build some heat into the tires), and then I continue about 130 miles up to 7,000 feet and temps probably into the 40's during the time I would get there. I would not start back until 2 or 3 PM so the temps should be in the mid 40's and I would take it very easy until I lost altitude and gained some heat before I would even begin to explore some cornering fun.... It's a beautiful road, though-- taking the posted 45 MPH turns at 75 is so seductive in the summer among the pines....

Thanks again for your experience!

 

The safety of these cars is one of the important features. Switching the tires is essential for below 35 degrees with or without snow on the tarmac. The ride and look can be very close to the summer shoes; if you go for 'V' rated performance.

 

On dry, sub zero road surfaces, summer tires will be more than adequate for normal driving once they have been driven on for several miles. I regularly drive my 996 on my summer Potenza's in temps below 0F, including cross country and through the rockies, with no problems. Obviously,1G cornering is not advised.

 

I am using the new Bridgestone RE-11's this winter for street driving. Very good dry traction down to 22 degrees, about as cold as it has been without snow this winter. They remain supple and don't feel like "hockey pucks" at all. Just my $.02

 

I too have been rather surprised with the com pliancy of my PS2s in the relative cold spell we've been experiencing here in Texas. Coldest I've seen in my area here was 23 degrees and while the tires never generated appreciable heat, they didn't feel that bad really.