Careful on cold tyres...

Anyone not living in CA or FL, feel free to laugh at me. Having grown up in chilly England, I should know better... This morning, after an unusually bracing SoCal night, I was making a left turn out of our drive onto a fairly busy road with dodgy sightlines. The decent gap I thought I was going for was suddenly made smaller by a fast-approaching S2000. I hit the gas harder midway through the turn, and on stone cold (35F?) P Zeroes was lucky to get away with no more than a very inelegant fishtail... Remember, it's not just racers who need warm tyres! (and preferably warmed-up brains, too) I'll creep away in blushing embarassment now.

I did the same thing this morning! - the thermostat on the car read 37 degrees. I let the engine warm up a bit in the driveway while I moved our other cars (I'm loving this lighter holiday traffic and driving the Porsche daily!). I pulled onto a main road two blocks from my house and swung the rear end out while a minivan quickly closed the gap on me. A soccer mom looked at me in disgust as she was passing me while I got the car straightened out.

On the upside, it woke me up far better than any cup of coffee!

Take it from a Chicago boy, summer tires are pretty worthless below 40 degrees (f).

Yessir!

I was in Michigan 3 weeks ago and got to drive my brother in law's new M5 - wow, what a car. But I told him he needs to put it away or put snow tires on it, as we almost killed ourselves on the cold roads (it was 32 out).

2 words...... WINTER TIRES.

Dell, you're never going to convince anyone in CA to get winter tires on a Porsche. Heck, what with the weather in NYC these past few weeks, I still haven't put on my cold shoes.

I know, I was just playing. My words were more aimed at the cold weather cities

You know the funny thing: I love changing the tires in winter because it means that I'm also changing the wheels. Gives the car a different/fresh look for 4-5 months out of the year what with the sport classics on mop up duty.

Global warming is going to kill the winter tire business

I have to confess that I'm not going to bother with winter tires. On dry days, I want to drive the car for my commute, which is urban. If it's nasty, I've got two other vehicles with winter rubber. We'll see if it works out. But I know whereof you speak: In my last car, one cold day, I expressed my relief at getting out from behind some kind of trolling eighteen wheeler downtown by accelerating 'con brio' around a corner. I did an immediate 180 degree turn and wound up facing traffic the wrong way on a one-way street. That one stuck with me. I use a light foot and give myself lots of space when it gets below 5 Celcius...

Yeah global warming can help me shovel the 30" of snow in my driveway.

No PSM, just the loose nut behind the wheel. At least this time I remembered not to overdo it with the countersteering.

Would not take the car out below 40F without winter tires... the rubber really hardens up.

Well, I'll certainly be borrowing my GF's Civic to go skiing on Saturday

And to make matters worse, my car came with old summer tires. I find that it's fine in cold weather, but the problem is in rain or snow. I'm thinking about going all-season instead of getting snow tires, because in Chicago, the average temperature year-round is around 50F and combined with the dry roads, snow tires would simply get eaten alive.

No PSM for me - I counter steered without yanking my foot off of the throttle and all ended OK.

No PSM on my car - I counter steered without yanking my foot off of the throttle and all ended OK. I really want to find the time to take a DE course with this car, as I want to enjoy finding the limits under more controlled conditions.

what about when you have been 'rolling' for a while - surely the rubber warms up? i guess it just depends how cold it gets...

I feel like I'm missing something here. Murph, the whole point is that you don't drive on the winter tires in the warmer months.

All-Season tires are compromise. They are "ok" in the snow, "ok" in the wet, "ok" in the cold, and "ok" when it's warm/dry. The real problem is that they are just "ok" and when it's nice out they'll never be great!!

In Chicago, the temperature can change from 60F to 30F in less than 24 hours. Similarly, we can get a warm, dry spell in January up to 60 or 70F. And because this car is my daily driver, I can't just change tires like I change my shoes (i.e., dress for the occasion). So the question becomes, which tire should I use? If I use summer tires, I will slide around in winter. If I use winter tires, I will ruin them by heating them up and overdriving them on those frequent warm days.

Agreed. I spoke with my driving instructor about this one. Since I'm a newbie at the track, he said that you will gain a 25% improvement in speed, handling, braking, etc., just by learning how to drive properly on the track. I don't think I can gain that kind of improvement going from all-season tires to summer tires...

In a light chill like a Socal winter, I think you're right. This morning the car felt normal on a tight turn onto the freeway ramp after about 5 miles, whereas yesterday morning's moment was straight out of the driveway.

You will not ruin winter tires if you drive them on a 60 degree day. Additionally, while Chicago occasionally gets a 60 degree + day in the winter I would hardly call them frequent. I generally switch to my winter tires around Thanksgiving and don't switch back to the summer tires until early March. I have not found the need to switch back and forth and have not damaged my winter tires driving on them during the odd warm winter day. Finally, I don't think it's a very good idea to take All Season tires to the track. They are a compromise tire and the track is not a very compromising place. In fact, you may very well find that your stock brake pads and fluid will not hold up very well at the track. Are you driving at Chicago Region PCA events? Maybe I'll see you out there. Good Luck!!

I guess I should have said, "when we do get those 60 degree days, I usually run my car pretty hard." I would tend to agree, but I found a review at Tire Rack that compares the Michelin A/S vs. Michelin P/S. They were surprised at how close these two tires were as far as dry track performance. When my driving instructor (Dr. Porsche) said that he runs all-season tires, it kind of sealed the deal for me... I just joined the PCA, but the Chicago region asks for an additional $40 one-time-fee, so I sent the check in last week. I'm not sure which events I'll be going to, but I plan to start off in Autocross at first. I certainly would look forward to seeing you out there. Any preference as to which tracks/locations for Autocross or DE?

I don't really attend many autocrosses anymore. However, the Chicago PCA runs a fantastic DE out at Road America every year over Memorial Day weekend. The first day of the event is set aside for beginners and instuctors only and the entire event includes three full track days at RA with a PCA instuctors plus classroom instruction from Skip Barber instuctors (for beginners, experienced drivers run in separate groups w/o instuction). Additionally, Chicago PCA runs a beginner day out at Blackhawk every year. You can find the entire schedule on the PCA (Chicago Region) web site. Hope to see you out there!

Heah, you used to have to wait 5-1/2 months for it to melt. Now you only have to wait 5-1/4 months.

to be honest, regardless of the temp, I don;t nail it straight away and always wait a little for the tyres to warm up, the colder it it, the longer I wait - just like the engine temp....

Normally I'm exactly the same, which is why yesterday was a bit of a surprise - I was trying to get into a narrowing gap, and even three quarters throttle at 3000rpm was enough to get a bit sideways.

Always watch out when acceleration midturn on any sports car. It must be done gradually even in good weather. Rain, snow and cold weather are especially tricky.

Folks, I originally come from Austria, so I know everything about winter tires and modern young winter tires (not older than 3 years otherwise the rubber gets too dry to grip) are great to drive in snow and on wet roads but believe me on dry roads no matter what temperature, summer tires always beat winter tires if they are warm (it's logic that it takes all tires longer to warm up when temperatures are low). Autobild, Germany's largests car magazine performs every year an extensive tire test and can always prove that the temperature fairy-tale is an invention of the tire industry. Harold

So living in Austria makes you an expert on tires? You do realize that the rubber compound of winter tires and summer tires are different thus allowing the tire to perform in temp conditions commensurate with the compound regardless of road condition? It's the compound not the label. The average consumer wouldn't understand what tire to buy if they were just labeled by compound so labeleling them winter/all-season/summer/etc allows them to buy the tire that best suits their conditions and those labels usually correspond to a temperature range.

I think what he's saying is that summer tires are always better on dry pavement, regardless of temperature, as long as they're warmed up. I never thought that was true, but I'd love to see something in the way of proof. Would be cool if true. Yeah, I didn't get the Austria thing either.

Yeah, I got that as well but that is where his argument FAILS. There is just NO way to get summer tires up to temp in the winter (cold) on dry streets with city driving. A track is a whole 'nother ballgame.

Imagine how bad it could have been without PSM.

Dell, coming from Austria enables to read more diversified articles as I've more than one language for my research. Here's a current link to Autobild: http://www.autobild.de/test/reifen/a...tikel_id=12460 And here's the quote: "Bei nasser und trockener Fahrbahn ist der Winterreifen mit seiner weicheren Gummimischung und den unz�hligen Lamellen dem Sommerpneu klar unterlegen. Weniger Seitenf�hrung, weniger Aquaplaningreserven und ein l�ngerer Bremsweg verschlechtern seine Leistungsbilanz auch bei niedrigen Temperaturen. Daran gibt es kein Deuteln. Auch wenn sich das M�rchen von der Temperaturgrenze bei sieben Grad Celsius hartn�ckig h�lt." And a free translation: "On wet and dry roads winter tires are inferior to summer tires. This is due to their softer rubber compound and enless fins. Less cornering, less aquaplaning reserves and a longer stopping distance downgrade their rating even at lower temperatures. That's for sure, even as the fairy-tale of temperatures below 7 degree Celsius (44.6 degree Fahrenheit) is still around." Harold

I guess all that censorship in the USA keeps us from reading anything other than Road and Track. You believe what you want and we will stick with published fact rather than magazine anectodal evidence. If you are serious about the performance of tires you really need to check out the data sheets published by the manufacturers for each compound. Until then, feel free to run your summer performance tires in the winter thinking that they will work better.

Dell touched on the issue that seems to always be forgotten or glossed over in the discussions of summer tires use in colder conditions. The normal everyday in and around town driving does not warm the tire up sufficiently to let the rubber compounds work properly. This is especially true in damp conditions. While it is true that you can drive summer tires in cold conditions (not snow, ice, rain, etc.) and never experience �problems� it does not mean when you need to stop, turn or accelerate in an emergency situation or the driver has became to confident and over-cooked an on ramp, that the tires are going to grip and perform the way they are suppose to. Daily driving on public streets is at such a threshold that the tires never heat up and are not performing properly, but the same reason why the tire has not achieved the proper operating temperature is also the reason that most of the time there is never an issue. It is the one time that you need to stop very quickly or turn or accelerate or hit a damp part of the road that you find out that the tires are not working the way they are suppose to. If this type of risk is acceptable to you then by all means drive your car on summer tires during the winter and realize the risk exist, but don�t try to rationalize the use (to yourself or others) based on the premise that the risk is not there because you haven�t experienced it before.

Dell the data sheet from the tire manufacturers must prove your point. I'd surely fire these guys as CEO of the company if they would not support my winter tire sales, academically your prove is worthless - sorry. However, the compound is a valid point but winter tires differ in a lot of other attributes from summer tires than the compound and a total of all attributes combined define the grip of a tire. Tire manufacturers usually do not publish data sheets of their tire tests. The only one was once Michelin. They tried to prove a shorter stopping distance of winter tires on dry roads at temperatures below 30 degree Fahrenheit; but guess what their measured distance was 25% above regular distances what proves that they tested it on slippery asphalt where winter tires really stop better. OK, you don't believe in German "magazine anecdotal evidence" fair point; however they actually publish test results compared to tire manufacturers. A solid source is the ADAC, the leading German automobile club. One of their tire experts says: "Theoretically the thermo-thesis is right, but the exact temperature when summer tires harden is not proven but it seams to be below freezing point". Conclusion is: it depends where you live and under which conditions you drive your car. No doubt that a daily driver in IL is better off with winter tires but I don't see that a weekend driver in NC or VA risks anything with summer tires on dry winter roads.

You just confimed what I have been saying. Maybe your comments were TOO general and mine weren't state specific. But suffice to say, that I have NO need for winter tires here in NC. I will use a hybrid tire with a great treadwear rating for my Cayenne. My other cars run summer max performance tires year round. They just don't see the road if it is too cold or especially adverse weather. So, I guess we were really saying the same thing from the beginning?

Harold, you'll have to excuse Dell's ignorance. He's just a silly American (from down south no less) and does not know any better. Most American's aren't aware that due to our war effort in Iraq all winter tire test data is censored by the Government. As you know Iraq has a very warm and dry climate. As such the US Military requires a ton of summer tires to outfit the fleet of Humvee's. They (US Government) censor tire test information so the US population will switch to winter tires and thus reduce the overall demand for summer rubber. Thankfully, your extensive language skills have uncovered this viscous plot. In all seriousness, I recently drove a Cayman loaner for 2 weeks in December. Our weather in Chicago during that timeframe was mostly very cold, but dry. My loaner was equiped with Michelin Pilot Sports and let me tell you they were lousy in the cold (dry) weather. They never got up to temperature and the grip was awful. Toward the end of my time with the Cayman we got some snow in Chicago. The car was downright scary in the snow on these tires. I was very happy to get the my 996 back (with Blizzaks). I just wish I was smart enough to read "Canadian", as I'm sure our neighbor to the North might have some interesting literature on the subject!! jk

I agree Dell, we are saying the same thing, you in English and I in DEnglish (=German-English) - sorry for the confusion This fall the "thermo-thesis" was a big deal in German media, so I wanted to share what the guys think that built our cars. BTW I do also drive my X3 with hybrid tires on wet or rarely snowy VA winter roads but on dry days year around, I enjoy my 911 with summer tires (usually not in city traffic anyhow).

I do that most cool wet mornings pulling out of my driveway. Even more with the light weight flywheel. I only do it with nobody around to see. It is a lot of fun to see how far I can hold it with the throttle.

I actually thought that the magazine reference was interesting. It's unfortunately true that American 'vertical' media (like car mags) are more editorially under the thumbs of advertisers than the Euro media are. (26 years in advertising is my license to make this observation!). So here's another question: When I drive on my summer tires in the cold, I accept and make allowances for poor adhesion. But I always made the assumption that in a panic stop, my stopping distances wouldn't be affected as much. I figured that much friction would heat them up real quick, so I'd still have half decent braking. Thoughts on that?

In my experience at the track it generally takes 2-5 miles (depending on track temps) of "warm up" to get summer tires or R compound summer tires up to full grip levels. At most tracks that means 1 or 2 laps cornering and braking at around 7/10ths. I really don't believe that one panic stop will bring the temps up that quickly. This is just my opinion and I have no stats to back it up.

Even at racing speeds the track temperature makes a difference to grip. Case in point: the lap record at Le Mans usually falls about an hour after dark, when the air is cool for power, but the track is still warm for grip.

I haven't fully put the car away just yet. It's amazing, I live about an hour outside of Toronto in the snow belt but so far....no snow! Usually we get dumped on end of November. Plus usually it's cold cold and cold, but right now it's 1�C or just above 32�F for the guys in the 'ol U.S. of A

Just curious about what kind of tire you run. Summer, all-season, winter?

That is correct. One panic stop will not bring the tires up to temp. If I get on the brakes hard with cold tires, the ABS will engage at relatively low Gs. If the tires are warmed up, the G-level is vastly higher before the ABS hits. I would concur that it takes several miles of very aggressive driving to get tires up to anything "really" usable, and my tire temps are noticeably less when the ambient road temps are lower. Recently, I've been collecting data of tire hardness (durometer) vs surface temp. It's really scary how drammatically tires are affected by temperature.

So do you guys not put too much credence in warming up the car before letting lose?

After driving a few miles this cold morning at 27 degrees F with the car fully warmed up I wound it up to redline thru 1st and 2nd while accelerating up a freeway on ramp. The ramp is like a big S with a tight left hander followed by a right that required steering input just as I had shifted hard into 3rd. Still full throttle just as I dumped the clutch the rear broke loose and slid a couple of feet to the left and hooked up again. Quickly looked and I was doing 70. My traction control was on but didn't activate as it often does if I push a little too hard on cold or somewhat frosty or icey roads. I didn't expect the back to break out but a week ago I was entering the freeway on a tight right hander a little too fast and the car pushed to the point of running off the road surface to the outside of the turn. This was embarrasing as I had to slow to a crawl and crank the wheel hard to get back on the roadway. This was below freezing as well and I now know I can get into big trouble with my P-Zeros on cold roads. I think I'll back off a few clicks untill the weather warms up a bit.

Also, don't forget to take it easy after getting BRAND NEW tires installed. A few years back in the hot summer heat, I went sideways into an exit that I take all the time, but this time I had forgot that I just had four new tires on the 964 and all hell broke loose. There was no sign of the tail coming around and it felt like I was riding on ice. I was very lucky that I caught the car before it went into the median.