Why can nobody drive in the snow

[Graveworm]

Onehp said:

But for traction, 4wd is great. Fields, steep driveways, pulling trailers, the odd rally session etc. My next car I want a rear biased awd with lsd in the rear and masive power, so I can test traction even in the dry

This is where we differ.Traction is not everything. As everyone knows a skid occurs when the force or forces acting on a wheel exceed the grip. On the same tyres grip is a constant. Cornering forces and (In most cases) braking forces are also a constant. It follows that if the force applied by the engine either when driving, accelerating or decelerating on any wheel is halved then there is less chance of a skid?.

In a perfect world there would be no engine force applied, except when the wheels are in the straight ahead but that means losing road speed in every bend and we live in an imperfect world.

[Tired]

Graveworm said:

This is where we differ.Traction is not everything. As everyone knows a skid occurs when the force or forces acting on a wheel exceed the grip. On the same tyres grip is a constant. Cornering forces and (In most cases) braking forces are also a constant. It follows that if the force applied by the engine either when driving, accelerating or decelerating on any wheel is halved then there is less chance of a skid?.

In a perfect world there would be no engine force applied, except when the wheels are in the straight ahead but that means losing road speed in every bend and we live in an imperfect world.

Please, don't try cornering at any sort of speed with no throttle, unless you like travelling backwards.

[jagnet]

300bhp/ton said:

The more worrying thing is, many winter tyre advocates on here seem to believe winter tyres give you the same grip as slicks on a dry race track. They do not. They certainly offer more traction than summer tyres, but the surface is still slippery and/or loose depending on the type of snow. So they will spin and the car will still slide.

No they don't. No one has ever suggested anything of the sort.

BTW, winter tyres provide traction and grip.

300bhp/ton said:

4wd did allow me to make a 190 mile round trip one winter, yes 190 miles.... All in snowy conditions. Again I wouldn't have dreamed of doing it in a 2wd car.

But that's just your personal decision based on your lack of experience with winter tyres. Many many people manage to complete far longer journeys in snowy conditions using 2WD without issue. And yes, before you ask, I do speak from experience.

There's what, an inch of snow in your subsequent photo? I promise you, you really don't need 4WD to drive 190 miles in that.

[Labradorofperception]

macushla said:

Labradorofperception said:

I'm a firm believer that the driving test should include a little bit of physics and engineering. Firstly, so that orange girls with painted on eyebrows and pcp'd white goods will understand that sitting 3" off someone's back bumper is not going to end well

and as for snow...

Try and teach people the physics of what is going on. What works and what does not. The difference between summers and winters and that even a top end Discovery is just a very expensive sledge if you hit and sit the brakes going down Willowmoor Bank, on the side of the Wrekin (yes, fat middle aged lady driving like a tt I am looking at you).

Even my Series 3 Lightweight spun it's tyres a few times - if there's ice underneath, you're going to have to think laterally.

so I'd teach:

The difference between summer and winter tyres
What 4 wheel drive actually is, and there is a difference between your haldex CRV and a Grand Cherokee
Engine braking
How to brake, and when
Gearing, speed and reaction times
That just because it says "four wheel drive" on Tiguan, it's not an Abbot self propelled gun. It has limitations, big limitations....

And you think someone is going to remember that when they drive in snow for the first time 10 years after taking their test. I’ve mentioned it already but there are demands that everyone should take a motorbike, van, trailer, truck, HGV test too. What about a full education in petrol refinery to encourage more frugal dribpcing styles and full insurance qualifications, maybe a full course in home, mechanics, maybe to Master Technician level for all top end brands.

Half an hour from the instructor, an hour self study and a few questions added to the driving test.

i'm not saying they should go do a weekend at Eastnor or being able to drop a clutch in a Nissan Mildred.

[thiscocks]

macushla said:

Nope, not convinced. I think the labelling as Summer Tyres has come about through common usage.

I’m going to take Michelin as an example.

They have Alpins - winter tyres
Pilot Sports (whatever number iteration) all year
Pilot Cup (cut slicks)

The Cup are definitely summer tyres as they really only work in the dry

The Pilot Sports are good for all year round. They may have a bias towards warmer temps but not exclusively restricted to that. They also have hefty tread patterns and are good in cold, wet conditions like most of winter is in the U.K.

Alpins definitely Winter tyres,but not snow tyres. Yet everyone complains when it snows that everyone isn’t on winter tyres. There is a difference between winter and snow tyres.

I know they’ve created this Primacy range but they seem to always be pushed during winter so hardly an all year tyre that gets heavily pushed in winter.

[macushla]

jagnet said:

macushla said:

The Cup are definitely summer tyres as they really only work in the dry

You're aware that it can rain during the summer? So a summer tyre that only really works in the dry is a bit pointless in the UK, no?

Tyres have developed in line with cars getter heavier, faster, and more technically accomplished. By necessity that biases them away from cold wintery conditions. Dedicated winter tyres were then developed to cope with those conditions and by virtue of not having to target summer conditions they could really focus on snow and ice performance.

All season tyres have been around for a while but it's only in the last few years that tyre tech has allowed them to better bridge the gap between summer and winter conditions. Previously they tended to fall far short of either.

Normal tyres are utterly woeful in snow and ice and therefore cannot be called all season tyres. Their construction and tread pattern is simply not designed to provide grip on snow.

Yes and you’ve spectacularly missed the point. I didn’t say they only work in the dry, I said they only really work in the dry. They have minimal tread and are designed for warm sunny sprays were their increased contact patch gives them their design advantage. I’ll guarantee that the guy using Cups is pottering around when it rains in summer, rather than aiiming for maximum cornering g force.

Ice performance. Really? You think any tyre can cope with ice? Unless it’s got studs / spikes then you’re a passenger no matter what you think.

I’m not convinced that winter tyres are the panacea everyone e thinks they are. A bit more thought into driving means you can cope with most weather conditions. And once again for clarity. Winter tyres are not snow tyres.

[Graveworm]

Tired said:

Please, don't try cornering at any sort of speed with no throttle, unless you like travelling backwards.

A trailing throttle is an engine braking force. Maintaining road speed in a bend requires more force from the engine than going in a straight line. Both increase the demands on the grip provided. In theory a freewheeling car on a level bend will be least likely to skid if it was freewheeling before during and after the bend. Of course suspension means loading isn't equal and cars are designed to do best when being driven through a corner.

[jagnet]

macushla said:

Ice performance. Really? You think any tyre can cope with ice? Unless it’s got studs / spikes then you’re a passenger no matter what you think.

Studded tyres are clearly superior to friction winters on ice, but the friction winters are still well ahead of summer tyres on a pure ice surface: https://youtu.be/dJj2BCnq5hM?t=51 That's with normal euro winters. Nordic winters such as the studless Hakkapeliitta R3 will do an even better job on ice.

Everyone, including the tyre manufacturers, refer to "normal" tyres as summer tyres. You appear to be in a group of one in wanting to redefine track day tyres as summer tyres and summer tyres as all seasons. Michelin themselves speak of the Pilot Sport Cup as being designed for the track, but one that's also approved for road use.

[FiF]

Graveworm said:

Tired said:

Please, don't try cornering at any sort of speed with no throttle, unless you like travelling backwards.

A trailing throttle is an engine braking force. Maintaining road speed in a bend requires more force from the engine than going in a straight line. Both increase the demands on the grip provided. In theory a freewheeling car on a level bend will be least likely to skid if it was freewheeling before during and after the bend. Of course suspension means loading isn't equal and cars are designed to do best when being driven through a corner.

To follow that up, I was taught by a certain gent named Blomqvist that if you are requiring every little bit of grip in a bend, especially in low grip conditions or if you've misjudged things, dipping the clutch and therefore technically freewheeling, is the way to get maximum grip quickly directed towards centripetal cornering forces. Once you're past the worst point and still on the island and in control then start introducing drive to drive it through. It's also The technique taught for some years now in the force skid school course.

[Onehp]

300hp/tonne and Graveworm.

I fully understand all the technical bits and that you get along very well with 4wd for perfectly valid reasons.

You don't get the human part. Normal people don't gauge grip, normal people don't go on the throttle mid curve. Normal people stay away from grip limits. Normal people will first notice it is MORE slippery then they though was the case when the car skids and esp/tcs/abs kicks in. This is the reason why 4wd gives a false sense of security, exactly BECAUSE it is BETTER in putting power down.

Think about it this way. In normal driving (dry, wet), the braking G a car can generate in an emergency is roughly 5x 6x more than what people experience as a comfortable acceleration (0,15G), 5:1 braking vs acceleration force. With a 2wd car, roughly, when the driver notices traction issues on slippery roads, there will always be approx 2x the braking force available relarive the accelerarion. With a awd, the braking performance can degenerate to 1:1 before the driver notices it is slippery.
I am not saying people can't adapt their driving, but I am saying people, on average, don't adapt FULLY. Also I am saying it is not wise to advocate 4wd as a solution for snow driving, when it contributes nothing to the safety aspect, that is hinderance avoidance and braking where the influence of how the wheels are driven are mostly irrlevant.

I am not in any way objecting to 4wd, I object to that 4wd would contribute to safe snow driving for normal people. It does contribute to mobility, which is not the same thing.

Neither are winter tyres or all seasons the answer to everthing. But they do contribute to mobility AND safety, ie being able to avoid accidents when grip levels are lower than expected. Also here people will compesate their behavior and take more risks, but on average they don't overcompensate.

Edit: assuming cars have ESP, very well documented to help safety by avoiding loss of vehicle control. And much more effective when there is some grip... Without, 4wd is better, awd even more.

Coming from someone living in Sweden since the stary of the millenieum, where people can't always drive either, where during winter most people are on winter tyres and where at first snow, some people have forgotten to put on their winter tyres and the consequences of that...

Edited by Onehp on Friday 25th January 12:38

[lyonspride]

macushla said:

Nobody has summer tyres, other than those running cups or other virtual slicks. The tyres we all have are all season tyres.

https://www.falkentyre.com/en/tyres/car-tyres

Very clearly states that my 914s are "summer tyres"

[Tired]

lyonspride said:

macushla said:

Nobody has summer tyres, other than those running cups or other virtual slicks. The tyres we all have are all season tyres.

https://www.falkentyre.com/en/tyres/car-tyres

Very clearly states that my 914s are "summer tyres"

Vredestein refer to the tyres I use as summer tyres as well.

Hey, what do they know?!

[Onehp]

ericmcn said:

Onehp said:

You might be technically correct that a permanent 4wd car will have been higher up the hill, however the reason it gets stuck are the inappropriate tyres.

At best, it might have been a few feet higher up accounting for marginal higher momentum from a better start with true 4wd in the initial first second or so, a marginal difference at best and completely unhelpful for the task at hand, unless your driveway was thas feet longer perhaps...

Overall, I think your comment is a perfect illustration of how much drive is overrated...

if so how can you explain the results on the video here ? its a Subaru with AWD and 50:50 bias but I am sure a comparable AWD vehicle would perform just as well.

https://www.youtube.com/watch?v=2OzK-oRPCbs

take your time.

Happy to comment.

First of all, the comments were for the front and rear axle lock-up. There both the Subis and Passat perform as expected. The two SUVs fail. I can't comment on the Highlander, US model. The CR-V is a known issue: https://teknikensvarld.se/honda-cr-v-4wd-system-is...
This isn't normal for a car that is supposedly 4wd. Yes bad cars exist...
As for the left right traction, this is as I wrote before here,basically a test of the vehicles electronic traction systems. Some are better, some or worse. But it has in essence very little to do with the distinction 2wd/4wd.

The good news is that the video is 11 years old and electronics traction systems have improved a lot.
Subarus are good at awd, but I can't help that the suggestive talk that the differences in traction left/right is because of symmetric drive is a bit fanboi. There is no substantiation and if it were an issue of symmetry, the non subies perhaps should have different results left and right. What the vid actually shows is that subare has better traction control systems than these three cars. Now 12 year old or older models.

So Subaru is good, but don't mistake these results as if they would represent all other 4wd cars on the road today.

Now that we have differentiate between 4wd systems, I still think a Subaru should wear suitable rubber if it is used on snow...

[macushla]

Tired said:

lyonspride said:

macushla said:

Nobody has summer tyres, other than those running cups or other virtual slicks. The tyres we all have are all season tyres.

https://www.falkentyre.com/en/tyres/car-tyres

Very clearly states that my 914s are "summer tyres"

Vredestein refer to the tyres I use as summer tyres as well.

Hey, what do they know?!

And you’ve lapped up their marketing BS. Let us know what your spring and autumn tyres are like too

[Tired]

macushla said:

And you’ve lapped up their marketing BS. Let us know what your spring and autumn tyres are like too

Well, I haven't. I didn't know it said that on their website until it came up in conversation on this thread and I went and looked. It had no bearing on me buying those particular tyres.

I've never seen spring or autumn tyres, but they do sell winter tyres, so what would you call non-winter tyres?

Seems calling them 'summer' is pretty reasonable, but then it sounds like I've been brainwashed into thinking this, so perhaps you can set me straight

[Car-Matt]

macushla said:

Tired said:

lyonspride said:

macushla said:

Nobody has summer tyres, other than those running cups or other virtual slicks. The tyres we all have are all season tyres.

https://www.falkentyre.com/en/tyres/car-tyres

Very clearly states that my 914s are "summer tyres"

Vredestein refer to the tyres I use as summer tyres as well.

Hey, what do they know?!

And you’ve lapped up their marketing BS. Let us know what your spring and autumn tyres are like too

its safe to say that you don't know what you're talking about......

[jagnet]

macushla said:

And you’ve lapped up their marketing BS. Let us know what your spring and autumn tyres are like too

Excellent, that should save me running two sets of tyres now that I know the only reason the PS4s can't get up the hill to my house in snow is due to marketing BS. I had previously put it down to harder compounds, longitudinal grooves and no sipes but now I know better.

[Pan Pan Pan]

Possibly one of the main problems with this issue, is that those who cannot drive in the snow, do not know that they cannot drive in the snow, and consequently drive out in the snow, only to discover that they cannot drive in the snow....and so on

[robinessex]

This works quite well

[Onehp]

Some people take things to literal. If you get this all the time, maybe you should get a diagnosis. No shame. A friend of mine was diagnosed with Aspergers at age 60 and it was a total relief.

They are, in fact, called summer tyres. They should be called Spring+Summer+Autumn tyres, three season tyres or allseason-except-winter tyres. Next time you need non-winter tyres, use any of these terms and you'll instantly know if they have friendly folks at your local tyrefitters...