Winter tires in the summer

[Yggdrasill]

Do you have a citation for that? because a frequent condition that winter tires have to deal with is a thin layer of water on top of ice, so generally I would expect them to do well in this situation (and the study I referred to earlier did not note that as a downside)

Here's one test Dyrt og livsfarlig å kjøre med vinterdekk - Dekk og Utstyr (Norwegian)

They used four different sets of tires; new summer tires with 8.1 mm thread depth, used summer tires with 3-3.7 mm thread depth, new winter tires with 8.6 mm thread depth and used winter tires with 5-6.4 mm thread depth.

The aquaplaning results when driving straight through standing water:

New summer tires: 82.6 km/h
Used summer tires: 69 km/h
New winter tires: 67 km/h
Used winter tires: 66 km/h

They also tested the tires when driving through standing water when cornering, and the new winter tires could handle only half the lateral force of the summer tires, with the used winter tires being even worse. (The soft rubber leads to the threads closing up when subjected to the lateral forces, and traps the water under the tires.)

And in the braking test from 80 km/h on wet asphalt, the new summer tires needed 37.7 meters and the used summer tires needed 39.7 meters, while the winter tires needed 50 meters. That means that when the cars with summer tires have come to a complete stop, the cars with winter tires are still going at about 40 km/h.

- - - Updated - - -

Of course, it's important to differentiate between different kinds of winter tires. Some winter tires are intended for city-use where you have a lot of wet roads and not a whole lot of snow and ice. Other winter tires (e.g. Nokian) are intended for snow and ice. The former will naturally perform better on wet roads while the latter will most likely not be as good on wet roads. The testing performed above is done on nordic winter tires, designed for snow and ice.

 

[mknox]

As I said, I read the Quebec ambulance study on winter tires and they found winter tires suitable for year round use in that application, with no real downsides, they recommended the practice be adopted nation wide.

I have to wonder if winter tires used on larger commercial vehicles like ambulances are like passenger car winter tires. What I mean by that is maybe the ambulance tires were simply like passenger car snow tires used to be years ago when the rubber compound was the same and the only difference is a more agressive tread pattern. Most large trucks I see have big knobby treads which is how I remember passenger car snow tires looking like when I was a kid. When I first saw "modern" winter tires, they looked like they'd never work based on how I remembered my Dad's old snow tires looked.

 

[mnx]

On a somewhat related note, when do you guys get rid of your winter tires? I think I read snow traction goes down significantly below 6/32" tread depth. Do people really scrap their winter tires at that point? The winters on my S are at that point now after 15,000km. I think I may run them one more winter and then leave them on through the summer (they are performance winter tires Michelin Pilot PA3's so not nearly squishy/snow oriented as other winter tires).

 

[mknox]

On a somewhat related note, when do you guys get rid of your winter tires?

Good question. I try to utilize mine as little as I can get away with by installing mid-November and removing mid-April (or earlier) so around 4 months of the year. I drive about 3,000 km a month, so that means I put about 12,000 km on my winters each season. That means, after two winters, my Nokians have about 24,000 km on them. They performed really well this past winter and, to the casual eye, looked great when I removed them, but I'm going to have to get my gauge out and see how much tread I have left.

My other ICE car has had the same winters for 8 seasons now, and they also continue to perform great and look to have tons of tread left. They are Goodyear Nordics and have wear bars in the tread pattern, and I'm nowhere near the wear bars yet. It gets used way less than my Model S.

 

[Yggdrasill]

On a somewhat related note, when do you guys get rid of your winter tires? I think I read snow traction goes down significantly below 6/32" tread depth. Do people really scrap their winter tires at that point? The winters on my S are at that point now after 15,000km. I think I may run them one more winter and then leave them on through the summer (they are performance winter tires Michelin Pilot PA3's so not nearly squishy/snow oriented as other winter tires).

The legal minimum here is 3 mm, and the recommended minimum is 4 mm. I replace the tires when they reach 4 mm. (6/32" = 4.7625 mm.)

Counting 3 mm as completely worn out, starting at 8.6 mm means that at 6/32", the remaining thread life is 31%. And at 4 mm the remaining thread life is 18%.

 

[RiverBrick]

...my Nokians have about 24,000 km on them. They performed really well this past winter and, to the casual eye, looked great when I removed them, but I'm going to have to get my gauge out and see how much tread I have left.


.. They are Goodyear Nordics and have wear bars in the tread pattern

The Nokians also have wear bars. Actually, they start with raised a snowflake and 8-6-4. The snowflake is basically the same as the four, when it's gone, they don't recommend the tire for Winter conditions. After 17,000 km, the eight on my tire is completely erased, but the six is still there.

 

[mknox]

The Nokians also have wear bars. Actually, they start with raised a snowflake and 8-6-4. The snowflake is basically the same as the four, when it's gone, they don't recommend the tire for Winter conditions. After 17,000 km, the eight on my tire is completely erased, but the six is still there.

Thanks. I'll have to check that out. They're in storage in my garage right now.

 

[beeeerock]

The Nokians also have wear bars. Actually, they start with raised a snowflake and 8-6-4. The snowflake is basically the same as the four, when it's gone, they don't recommend the tire for Winter conditions. After 17,000 km, the eight on my tire is completely erased, but the six is still there.

I did not know that! I'll be checking my tires tonight! :biggrin:

 

[RiverBrick]

Here's an image of what came with my Nokian R2. I'm not 100% sure if the snowflake is the same as the four, though. Maybe someone else can google nokian tread wsi and understand the faq better.

 

[Yggdrasill]

The snowflake is 4 mm according to my googling. DSI and WSI indicators (Nokian Hakkapeliitta R2 SUV) / Nokian Tyres

 

[green1]

The nokian "wear bar" system is the best system out there I think, it's easy for even the lay person to understand, and you can tell at a glance how far away from replacement you are.

 

[samcarney]

The nokian "wear bar" system is the best system out there I think, it's easy for even the lay person to understand, and you can tell at a glance how far away from replacement you are.

Although they are considered all season and not winter tires. Continental DWS Extreme Contact tires have something similar. (D)ry, (W)et, (S)now.

 

[Raffy.Roma]

I saw this thread right now that I decided to use the winter tires of Mercedes SLK also during the summer. In fact I feel very comfortable with the winter tires expecially in the bends where I need grip.

 

[DrGuest]

I just put on the Continental DWS Extreme Contact tires, an all weather radial to replace my Primacy MxM4's which I went thru in 10,000 miles. We got 12 inches of snow last Wednesday so I was really glad for the extra grip taking my son to school in a Blizzard, passing accident after accident. I am going to use the Michelin Ice3's for my winter tires because we are are a dry climate and get dry bare roads between storms in the Winter. The Ice3's should give me a better feel on dry pavement but get me thru the snow when I need them. I found thePirelli Winter Sottozero's an inadequate tire for Montana's deep powder snow and hard packed snow, or ice. They were super soft and worn down to 4mm in 10, 000 miles. I'm pretty sure I'll get a bit more mileage out of this new setup and I am mellowing my driving style, a little, as I mature in my ownership of 16 months. Most fun car I have ever driven! I had The Conti DWS's checked at 2,200 miles and there was no wear and every thing was even all the way around.

 

[simonog]

After 20 years of racing (though not a Tesla), I have made a practical study of grip, and when it goes! If we focus entirely on performance and ignore cost, wear and driver ability there are a few key considerations.

After reading the whole thread at one sitting I'd say that it is impossible to generalise as specific tyres type and weather conditions matter.

Running a tyre such as the Pilot Sport 2, which is as near a slick as one is allowed as a road tyre in the UK, and is a summer performance tyre, at its working temperature (determined by driving style and ambient temperature), it will outperform any winter tyre up to its water clearing capacity. Above that wetness level, tread wins as it's all about water clearing. Above the clearing capacity of the winter tyre, both will aquaplane.

Generally, winter tyres work better at cold temperatures even in the dry because the performance tyre can't reach working temperature. There is no binary better/worse for all conditions, and there is a crossover point.

 

[tga]

I saw this thread right now that I decided to use the winter tires of Mercedes SLK also during the summer. In fact I feel very comfortable with the winter tires expecially in the bends where I need grip.

You may find that you don't like it, especially once the weather warms up.

#1 - A problem that I haven't seen mentioned, related to handling specifically, is that the tread blocks on winter tires have multiple cuts in them ("sipes"):

The sipes help ice traction by extracting water from the surface via capillary action, increasing traction.

The downside is that, on dry pavement, it really messes up your handling. The small tread blocks can move independently, and the tire gets very "squirmy" in cornering.

See also: Siping (rubber) - Wikipedia, the free encyclopedia

#2 - I also feel that winter tires don't have better high-temp handling on dry pavement. When the soft compound gets warm, the tires feel "greasy" to me, and slide around a lot. If that's what you want, OK. But if you're going for traction at high speed turns on the Autostrada, you may be in for an unpleasant surprise.

If winter tires in the summer were so great, why wouldn't winter tires just be re-branded as all-seasons and sold as such? Oh yeah, because all-seasons are a compromise and, thereby, suck in all four seasons. :smile:

 

[dsm363]

Agree. Definitely take the winter tires off in the summer.

 

[bart513]

Dr. Guest is talking about a Model S not a Roadster btw. Am I correct? That does make a difference as they are 2 different types of vehicles (under the same Tesla brand of course)

 

[Stefan T]

Dasn't matter if it is a S or a Roadster
Winter tire on summer is still not good
And if there is spikes in them is worse

 

[GVTesla]

Bit late to the thread, but here's my experience.

My summer tires are the known Y-07's
My winter tires are the (probably also quite well known) Pirelli Sotozero's in back and a Pirelli Snow...(patrol?) tire in front (both the standard issue Tesla Roadster winter tire).

I find the Y-07's performance on dry excellent, no matter the temperature (as long as it is above, say 5C). They warm up quite nice and have an extreme grip. As soon as things get wet, they loose grip, so more caution while driving is recommended. They are definitely built for the dry.

At one point I drove the Pirelli's way into warm temperatures (like 15 to 20C). The performance of the roadster was so much less. The tires are, by design, extremely soft and only get softer with every centigrade extra. And they have a wobbly feel over it, even while driving in a straight line forward. This must be because of the lamel-structure to loose the snow. It does not feel comfortable at summer temperatures, or safe for that matter, as braking distance was also compromised.
They (the Pirelli's) performed excellent in the snow I've encountered, though in part it might be because of the excellent behaviour of the roadster in snow.

My personal choice is that I change to summer tires as soon as temperatures are expected to be constantly above 1C. Generally this is from half of April to somewhere into November, here. To me it seems that the Y-07's are the only tires that do the roadster justice The winter tires are there to conquer snowy conditions and/or the extreme wet conditions of late autumn.