Kevin K

I know that my OEM summer tires would suck in the snow - got that point well driven in from all the previous posts on the topic. And looking at the on-line tire specs for my SportContact2 Continentals, 44 degrees is the temperature below which the tires are not recommended (in reading the manual or the tire ads, it just says "near freezing temperatures." I was a bit surprised that 44 degrees counted as "near freezing.")

So taking that all in, my question is whether or not my summer tires will give me noticeably degraded performance at temperatures, say, 45 - 50 degrees. A lot of winter days are in that range here, and I'd like to drive the car (c2 cab). The car only sees dry roads and I wouldn't use it in any kind of wet/snow pack situation even at >45 degrees. Is there much of a performance curve, so that 50 degrees is worse than 60 degrees and so on until at 44 degrees and below they simply become unsafe even on dry roads?

For those who use their summer tires in the way I've described, do you need to drive any more gently?

Thanks for sharing your experience.

Kevin

Edgy01

Tire manufacturers have reached compromises in their designs with "all Season" tires but the true summer tires that usually are supplied on these cars are just that. I would not venture into that grey area with them as tires are a critical part of the performance package in a 997. Much of these cars were designed about the tire technology available today. (19 in rims, for example, and the 30 series size for another and how the suspension has been radically beefed up from the 996s).

GSIRM3

I live in Raleigh, NC with similar climate to yours. I drive my 997S with summer performance tires daily, as I did my previous e46 M3s. Keep in mind that I am talking about street driving, and not street racing. I have never had any problems. Obviously, the summer tires are not recommended for snow, but for normal street driving, I have not had any problems.

Jerry Fisher

I had my car out last week. It was dry but cold---30 degrees. You definitely have to slow down..the summer perfomace tires just don't stick in cold weather. Driving as you would in summer could BE DANGEROUS TO YOUR HEALTH.

Speed

I had two 996s with OEM summer tires that I drove during the winter. On dry roads I really didn't experience any problems in normal driving. When it was raining (but not snowing) things sometimes got a little "squirrely". When it snowed, even a fraction of an inch, the cars were almost undriveable. On my 997 I have a winter wheel set purchased from Tire Rack and it makes a big difference. Car is a lot more sure-footed in the cold and wet and in light snow.

Kevin K

I'm talking only normal driving in that dry road 45 degree range, definitely not at temps below the tire spec (the 44 degree mark) and definitely not on wet roads.

I just want to be sure I can hit a cloverleaf the same as I would in a normal car (with the obligatory all season tires) without slowing down to the point that the lady in the mini-van behind me hits my rear end. Now that would just make my day.

Kevin

geof

Interesting thread.

I wonder how the tires themselves warming up factors into this. I once went on a mountain drive in summer tires, but the temperatures on the ridge dropped to the low 20's Fahrenheit. The road was completely dry and empty and I drove gently, knowing the tires wouldn't be at their best. However for curiosity I stopped the car and felt the tires with my hand- they were warm! I also did a hard brake, just to see what happened, and the braking G's I felt were more than anything I had felt in any other car.

So, if the tires are warm, and the road is dry (with no chances of ice patches sneaking up), how low can one go with Summer tires? I've seen no discussions of this, either on Rennlist or elsewhere.

This is somewhat of an academic question for me anyway. Being in DC, in winter we get plenty of 50+ deg days where summer tires are fine and I can go have fun. (It's gonna reach 65 tomorrow- too bad I'm stuck inside writing a proposal.) Other days, the car is in the garage, with the battery nursing electricity from the outlet...

greenhouse

I'll pose a slightly different question, which would let me know how long the season for each set of tires is. At what point if you graphed the traction- temperature curve of 19" summers and 18" winters at what temperature do they cross? Obviously weather matters so assuming dry roads. Also, what happens to winters as the temp goes up? Is a just a flat performance or are there wear, traction etc. issues?

Frino

19 degrees in DC last week and no worries on the PS2's (19's). You'll be fine so long as the roads are dry, you allow for longer stopping distances, and keep your inner Enzo in check.

rmillnj

The real risk is those nice sunny winter days where the roads are dry but the temperature is only in the 20's. As long as you remember you are driving around on marbles and don't push the car like you would in the summer, you will have no problems. But if you have to do any radical manuvers or hit that cloverleaf too fast, you will find out very quickly why there is a need for winter tires on this kind of car.

helispud

Last year when I took delivery of my C2 with 18" PS2s (on January 18th) it was around 10 degrees for the 165 mile drive home. I have since driven the car in temps as low as 5 degrees. While there is no doubt they don't stick as well as when it's warmer, you can still drive on dry roads. Just take it easy and you'll be okay. That said, I'm mounting up a set of Yokohama all-seasons this week.

Kevin K

Responding to rmillnj: I'd agree with you, especially given that the 20 degrees you cite in your example is well below the 44 degree mark that the summer tire manufacturer warns of.

I'm just wondering how steep the performance fall off is at, say, 45 - 50 degrees. This temp is above the manufacturer's warning, so one could assume that there is no added risk at this temperature because at anything above 44 degrees the tires perform fine. Or are they marginal until you get to some higher number?

As someone else noted, it would be interesting to see a performance graph showing the drop off as temperatures get closer to the 44 degree warning mark. If there is a steep drop-off, does that mean that my summer tires are much better at 80 degrees than at 60 degrees?

I would have to think that the lawyers for the tire manufacturers would warn of something about degraded performance at temperatures approaching their "not recommended" mark if there were a significant change in the tires' performance at temps close to but still above the minimum.

Maybe I'll be able to get some more info from the manufacturer to share here.


Kevin

rfedele

Winter tires perform very well in warm temps, but the tread loss is frightening. Car and Driver did an article/test on just your question a year or so back. As you would guess the all-seasons performed poorly no matter the conditions.

Dr. Car

Here's a pretty specific answer to the question about performance in the 40s: on a 45 degree morning in which my car was parked outside overnight, I tried hitting a a sharp freeway on-ramp at maximum cornering speed like I would on a warm day; this corner is a suitable test because I know the corner very well and it has a vast amount of paved runoff room. I am used to what the car's limits are because I track the car pretty often.

So what happened? I found there was a lot less traction at 45 degrees than on a warm day: big understeer followed by oversteer as the corner went to off-camber, and a robotic PSM intervention to speed up the correction process. I have the opportunity to take this corner regularly in my sedan which is on UHP all-seasons, and I haven't experienced the same amount of traction loss at this temperature in that car. Keep in mind this is just two seat-of-the-pants data points, I think getting feedback from a tire engineer would be a lot more telling.

David A

Michelin says "Summer tires are design to work above +7C"