Hello everyone,

I wonder that now the weather Is getting cold, and there is rather more rain in the area I live, I wonder on what kind of circumstances should I avoid driving due to slipping risks?

I definitely would not drive those cup 2s under snow conditions. There is only snow around twice a year in my city area of Vancouver Canada. So I still want to drive the car when it's getting cold. The temperature here is around 8 to 12 degrees usually I would say. I think that I would avoid snow and wet grounds with cold temperatures. However I am not sure if there is a range that people find to be safe to drive in, for example drive when it's warmer than 8 degrees or avoid the wet when cold or if slightly cold conditions it is still drivable?

Thank you
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Summer performance tires are not recommended to be driven below 45F/7C and not stored at cold temperatures. The compound gets hard at cold temperatures and grip will quickly diminish. The colder it gets the higher the risk of cracking as well. The Cup 2 being a streetable track tire will do worse at cold temperatures and in the wet compared to the PS4S for example. The Cup 2 also starts with less tread depth than regular summer performance tires, so you'll much quicker have not enough tread to dispel water and aquaplaning becomes more likely. FWIW, I drive on PS4S all year around here in the San Francisco Bay Area. At times it gets into the mid to high 40s. The lack of grip starts to become noticeable even when temps fall into the 60s/~15c. Still drivable above 45F/7C, but just need to be aware of the potential lack of grip and adjust driving style. Once the tires heat up from driving the grip improves. A good idea is to keep the tire temps displayed in the instrument cluster, so you can gauge the grip based on their temps. The Cup 2 needs to be around 190F/87C for full grip, so that gives you an idea.

Below is a graph from Michelin that shows Dry Grip vs Temperature, so you can see grip falls off quickly at lower temperatures. With wet conditions it's all that much less.

 

https://www.pca.org/sites/default/fi...r-TTW-2018.pdf











Again above tests shows the results for specific tires, eg Conti 6 for summer tire, and Cup 2 might be worse in wet conditions eg based on tire rack tests (no temp given on tests):

https://www.tirerack.com/tires/tests...y.jsp?ttid=262

• What We'd Improve: It needs more wet traction to be competitive here."

How I survived a blizzard in a Corvette Z06 on P4S summer tires

 

I also live in the GVR and, although I consider my GTR to be primarily a track car, I do like to take it for a little run at least every couple of weeks (even in the "winter" ... AKA rainy season). Once the rains start, I try to find a "mostly dry road" day, but that's not always possible. In any event, here are some things you want to consider if you're running the normal Cup 2 MO tires (some of this I've stated in multiple posts, but it bears repeating):

- Cup2 MO tires get noticeably and quickly/progressively harder below about 15 deg C (60 Deg F) and their traction (and [minimal] ride quality) rapidly degrades with that increasing hardness ... to the extent that throttle smoothness/management quickly becomes extremely important if you don't want the rear wheels to break loose -- because when they do break loose, any lateral sliding is likely to be much less controlled than it is on up-to-temp Cup2s (think "more like icy road" behavior)

- on a damp track at ambient temps above 20 deg C (68 deg F), I've been able to get tire temps up to 50-60 deg C where a solid 0.9+ G lateral grip was attainable, but very dependent up the "dampness" and composition of the surface (and a Porsche following me crashed)

- on a wet surface (with tires below 50 deg C) from auto-cross track and road track data on a C63 S and GTR Pro, I've seen that the Cup2 MO tires are consistently good for only about 0.6 G lateral grip before they slide (by comparison, PS4S tires yield slightly over 0.9 G lateral grip) ... so I don't attempt even mildly aggressive cornering under such conditions

- on a wet road at temps below around 10 deg C (50 deg F), stabbing the throttle will break the rear wheels loose reliably at any speed up to about 130 kph (80 mph) and sometimes at speeds up to 150 kph (93 mph) ... I've played with this while running down the middle of a straight at the track

- I wouldn't drive a car running any of the high-performance summer tires (Cup 2, PS4S, etc.) at temps below about 7 deg C (45 deg F)

All of this means that driving in our rainy/cooler/"winter" conditions is much higher risk due to the increased braking distances, reduced ability to make evasive maneuvers, increased risk of lateral sliding, etc. OTOH, for me, leaving the car sit too long without being taken for a fully warmed-up run is also not an option ... so I just behave myself. $;-)

 

There is good information above regarding summer tires and risks.

In my personal experience, I found summer tires grip to be very marginal at temps below 45F .For the last 3 winters, I put on the Michelin Pilot Alpin PA4 during the wintertime here in the northeast USA. I get excellent grip on wet or frozen roads (not ice or snow) so I can enjoy my car during the winter season. (I use 335/25-20 rear and 265/35-19 front)

 

Cup 2's in winter? LMFAO, you are nuts.

I've driven summers in the winter and that was dumb. Cup 2's are basically semi slicks and a whole nother' level more dangerous than even summers when using them in the winter. They aren't even recommended to be driven in wet weather when it's HOT out.

Also, correct me if wrong....if you got in an accident with summer tires in the winter some jurisdictions will assign fault to you for unsafe equipment and you can bet insurance companies would dwell on this.