What temps have you successfully driven the summer tires in? Thirties? Twenties?

Here in Maryland, we only have three or four cold months, so I'm also thinking that maybe I could stay with the summer tires if I don't drive in the snow, drive gently in thirties, and try to avoid driving in the twenties or lower (which isn't often around here). Plus, we have an AWD wagon and I'm putting all-seasons on the C63, so we'll have options other than the Porsches if needed.

 

Another possibility is to get a set of Pilot Sport A/S Plus: http://www.michelinman.com/tire-sele...formance-sport#

Anyone have experience with them?

Supposedly, they're "ultra-high performance" all-seasons, and rated well, though I still wonder how much of a performance compromise they would be compared to summer tires (eg, PS2).

 

I had my c4s in the mountains this morning (w/ Mich. PilotAlpin pa2); great road. The tires were warm BUT the road surface, though clear of snow, was in the shade, therefore cold and had latent salt on the surface as well. The car was a bit loose on the coldest of the turns. I pushed hard on the turns w/ sun but cautiously backed off in the shade.

The point is it not just the correct tires, warmed and inflated properly; conditions can determine your fate. We see a ton of drivers from the south in 2 1/2ton SUV's w/ all-season rubber driving in the snow like their going to crash because their ride is ill equipped for cold and snow. Then they wonder when I go flying by and twice the speed; good equipment is essential. It's the driver's responsibility to manage their ride and be aware of the limits.

Interest data from Manifold (perkinelmer) but this is a generic tire graph. A true high performance snow tire will test differently.

"Car tires are manufactured
from different materials because the different areas have to
meet different requirements"

 

K-E-V post : The car handles fine as long as you don't drive (like) a jerk and keep a good distance between yourself and the vehicle in front.

The above statement suggests a 'limp home' mode not driving a pcar. Clearly the vehicle doesn't 'handle fine' if you need to adjust your following distance. The reason we have these cars is to drive with focus and intelligence, and sometimes aggressively.

 

Hmm..... what ever sinks or floats boat is fine with me. With and without snow tires, you should keep a good distance between yourself or the vehicle in front, especially in the cold, unless you don't care about your car.

Yep, mostly in the 30s. We don't have really cold weather here. I have Pirelli P Zero Rosso on my E55. You can definitely get away with it as long as its fresh snow or dry pavement. As soon as there's ice, then forget about it.

I lived in Madison, WI, and Boston, MA for a total of 11 years, so I have a good amount of experience driving in snow.

 

http://www.1010tires.com/store/t-Winter-Tires-USA.aspx

Someone in another forum provided this graph. It looks somewhat generalized, so I'm not sure how much to trust it, but it's the most specific graph I've seen so far. If the graph is accurate, some implications:

- All three categories of tires have the same "performance" (however that's defined) at 7 C (45 F, not 40 F).

- Winter tires have poor performance at warmer temps.

- The drop in performance at lower temps for summer tires is somewhat gradual, rather than sudden. So not a dramatic difference between 40 F vs 35 F.

- Summer tires need warm temps (above say 70 F) to get close to their full performance. It's not that everything above 40 F is equally good.

Thoughts?

 

The past two months the morning temps have dropped to high 40's to low-mid 50's in s. cal and I noticed a pretty decent drop in traction for the first few miles. I have noticed some understated but more oversteer (slight slip). I have approx 8K miles on the set and good tread left on all tires. I'll be looking to try another brand of tire come this summer - just to try. I'm running Bridgestone RE11s (305s in the rear). Previous set were PS2s.

 

http://www.tirerack.com/tires/tirete....jsp?techid=73

Looks like the rule of thumb is that 10 F change in ambient temp means about 1 psi change in tire pressure.

I've been closely tracking my tire pressures lately, and have found about a 3 psi increase after 10 or 15 minutes of normal driving, so maybe that means the tires are warming up by close to 30 F. That suggests that driving the car may significantly compensate for low ambient temp.

Addendum: I just ran a quick calc based on PV = nRT, and the rule of 10 F for 1 psi looks to be accurate. I came up with 0.7 to 1.0 psi.

Further update: Went for a drive this morning. Started in the garage at 55 F and pressures of 33-34 psi. Outside temp was in the low fourties, but the pressure didn't drop, and then went up to about 34-35 in 10 mins. Took a little break, restarted at pressures of 33-34, entered a very curvy road at spirited speeds, and came out of that road at 36-37 in about 5 minutes. Moral of the story is that pushing the car seems to warm up the tires fairly quickly, at least as long as ambient temp isn't too cold.

 

just thought I would post my new winter wheel set. Pirelli Sottozero 240 series 2; 295 30 19; 235 35 19 on OZ Ultraleggera HLT with TPMS from Tire Rack(Damon); on/off easy at Tru-line in Seattle. Stored Mich PSS for winter on Sport Design wheel till March? Signed up for local Porsche club Winter driving skills at Bremerton Jan 7 to explore these tires in a controlled environment.

 

the Porsche Winter skills course should be great.....please make sure you report back on the experience.

 

Had a rainy, stormy, windy day sept 26 at the Pacific raceways track. Proformance lapping afternoon on PSS tires, new since July, temp in 50s. Drove for 3 hrs( two solo). Puddles on track, doesn't drain well so the chief instructor wanted speed not topping 100 because of standing water in the kink in the straightaway. ABS on for several turns even avoiding puddles. What fun though. Track virtually empty that day.