Is a Felicia safe with winter tyres on front only?

[jonny a]

What about one winter tyre on the front and one on the back? Surely the best of both!!! Te he he

[djaychela]

Well, I ran my Felicia the other week with Kumho R700s on the front, and non-grippy tyres on the back, and it was fine - probably had twice the grip of the road tyres (in a quick 20mph hit the brakes on my road test). Gutted I sold it now, as I could have had a right play in it today, as it's snowing again here (plus the FIA changed the rule that led to me selling it, gits!).

Interesting seeing the "higher gears are better" because of the torque division factor of the gearboxes, which on the face of it makes sense; however, it doesn't because you're not solely applying full throttle and a lower gear gives you much more control (and also given that you will probably be in a position to stay mostly in first or second, you will also not have to try to change gear in a panic should you need to use the engine to get you to slow down to a near-standstill). In my TDi Focus a higher gear and a footfull of throttle leads to a massive wheelspin, and a huge increase in the car's speed. Doing so in a lower gear leads to more wheelspin but less of an increase in speed because of the gearing and also I would imagine because of the greater break in traction. Again, it may be the IAM's approved thing (in the same way people on forums say X, Y and Z), but having driven a fair bit in the snow (including on the Recce for Rally GB 2008 which was snowy enough to get Loeb to crash his recce car), I know what I'll be doing. Not to say that I don't think I can learn/improve, but there's an awful lot of complete crap peddled on forums by people who couldn't drive a greasy stick up a dog's bum.

[RobinSLXi]

Oops! Didn't mean to light touch paper. I think the argument's been done to death on just about every car forum ever, but yeah.

Hehe, don't worry, it's not you that set me off, it's the general lack of common-sense thinking shown by so-called responsible authorities spreading outdated misinformation. The fact is, all car companies and tyre manufacturers do their own private research for their own gain - most of the freely available independent research either harks back to the DoT research of the '60s and '70s, or is about specific aspects that cannot be accurately extrapolated into general safety.

Example: the 2007 Highway Code still says the 'typical' stopping distance from 50mph is 53m, of which 38m is braking distance. However an AA road test from 1998 of my 1.6 Felicia (with primitive ABS acting on 1980s single-piston sliding calipers and drums, remember) found an average braking distance from 50mph of around 26m, which they rate as 'adequate'. Even assuming the same 15m for reaction time, that's still nearly 23% better performance than 'conventional wisdom', from a car that is quite frankly below average these days.

edit: Of course I forgot the FWD/RWD confusion - conclusions drawn from Ford Anglias and Morris Marinas don't apply to the majority of cars on the road today in this respect either.

Then misleading toss like this is spouted in a manner that most people might interpret as meaningful advice: (one sentence picked at random from worryingly many possibilities)

Industry research suggests if the new tyres are fitted to the rear wheels, water on the road surface is better dispersed, which improves straight line braking ability.

Let's see... (please nobody accidentally take offence at this, I'm addressing the 'you' comments at Tyresafe, not anyone here)

1. First off, where's the citation for this research? I for one wouldn't mind seeing the original data, if only out of interest. 'Unpublished research' is a synonym for 'we just made this up' unless shown otherwise.
   
2. 'Suggests'. So this is merely an interpretation rather than anything conclusive, meaning for one thing it cannot possibly be unbiased. If the study isn't finished, you can't draw conclusions from it yet, so shut up. If it is finished, it will have a conclusion that something is either proven or not, so quote that. The only reason not to would be if the actual conclusion disproves the point you're trying to make...
   
3. The statement barely makes sense anyway - how exactly is water 'better' dispersed, relative to the contact patches of all 4 tyres (which is the only relevant measure)?
   
4. Water dispersal is only a serious issue if there is so much on the road as to risk aquaplaning - anything that applies in this situation is hardly relevant to average conditions, and especially dry roads.
   
5. Whilst physics dictates that from around 60% to 100% of a vehicle's braking is done by the front tyre(s), braking will somehow improve with relatively less grip at that end given the choice, will it? Really?
   
6. Many drivers like to do things other than straight-line braking, such as steering round corners without sliding into a hedge. Care to mention how choosing to have less grip on the steering wheels may affect this?
   
7. And so on... (just from this one sentence )
   

p.s. I know I've not cited my statements here either, but there's nothing you wouldn't find out in half an hour or so reading up on the subject. Besides, in this day and age, we can easily fire up Gran Turismo or similar to get a general idea of how tyre grip affects braking and handling - yes it's not real life but it's good enough in terms of the basic mechanics to disprove most of this nonsense.

OK, rant over, I'll step back now I'll just say I'm definitely with the rally driver on this one (especially the 'greasy stick' comment - superb!).

Edited 20 December, 2010 by RobinSLXi

[AnotherGareth]

Why is it a legal requirement to change car tyres when the tread depth gets down to 1.6 mm?

What happens when driving at speed through pooling rain if the rear tyres are bald?

The answers to these should help people decide what's best for them.

[djaychela]

We're not talking about bald tyres though.... :wonder: and the answers to your questions are obvious. But I'd still take bald rears over bald fronts!

[AnotherGareth]

We're not talking about bald tyres though.... :wonder: and the answers to your questions are obvious. But I'd still take bald rears over bald fronts!

So obvious that you don't answer.

Considering the first question ... most people only change their tyres because they're forced to, but the reason for a legal minimum tread depth is so that they provide at least some grip in very wet conditions. A small number of enthusiast drivers change their tyres when there is only 3 mm of tread. I wonder why.

Then the second question ... say you've got newish tyres on the front and something close to the legal minimum on the back, and it's a very wet summer day. The problem you have starts when the back starts to slide, irrespective of whether the car is fwd or rwd. If the back does start sliding then it tends to go very quickly and with little warning, so if you're a driving god then you'll do fine. The only way to stay safe for the average driver is to drive significantly slower, perhaps even stop until the rain eases and the water begins to drain away, but there's nothing to tell them how much slower is safe.

On the other hand if the rear tyres are better at dispersing standing water then the limit of grip is at the front, and it's fairly easy to feel when grip at the front starts to go and just ease off the throttle to recover.

I expect it's similar when driving on slippery winter surfaces.

[RainbowFire]

edit: Of course I forgot the FWD/RWD confusion - conclusions drawn from Ford Anglias and Morris Marinas don't apply to the majority of cars on the road today in this respect either.

This is 100% true. The Marina would hold the road like a bar of soap, even on a dry day. Those were fun days. ;-)

(Cross-plys and leaf-spring suspension!)

Alex

Edited 20 December, 2010 by RainbowFore

[RainbowFire]

Water dispersal is a non-starter here. We're not dispersing water, we're trying to traverse snow. We're not driving *in* water, we're driving *on* snow and ice.

In the rain the tyres are dispersing water and allowing the rubber to have as much contact with the tarmac as possible to allow as much traction as physically possible. In the snow, the lovely grippy tarmac is buried. Inherently snow and ice offer way way less grip than tarmac. To the best of my knowledge, there's no tyre that clears the snow and ice down to the tarmac. (Even spikes and studs don't)

From here, it's all about snow and ice, rain isn't here.

Whether the car is FWD or RWD is a major factor. RWD will oversteer more easily, you'll loose the back (as everyone seems so worried about) and stuff it in a hedge. FWD has a tendancy to understeer, so you'll loose the front more easily. However, oversteer and understeer both occour predominantly on corners. If you've got your FWD to oversteer, it's because you went into the corner too fast and then hit the brakes too hard or just lifted off the throttle too fast. But even in the snow, you'd only manage that because the front wheels had more drip than the back ones. Having the front wheels with the better traction in the snow and ice mean you're better able to avoid getting into a mess in the first place and have a better change of influencing the car if you do.

Once you've locked the wheels, you're just a passenger to physics anyway, regardless FWD, RWD, 4WD.

I suspect that you'll see a lot more incidents in the current weather where the front of a car is damaged (showing oversteer and loss of traction at the front), than you will the rear.

Obviously in an ideal world, we'd all have 4 fitted, 'cos we'd be able to afford a second set of rims, tyres and storage.

Alex

[AnotherGareth]

Water dispersal is a non-starter here. We're not dispersing water, we're trying to traverse snow. We're not driving *in* water, we're driving *on* snow and ice.

You might have thought that but I was discussing driving in slippery conditions and how the relative abilities of the front and rear tyres to grip results in differing outcomes.

[djaychela]

So obvious that you don't answer.

Yes, well, I thought so - not a case that I can't answer it, but anyone who can't work out why there's a limit there really is stupid. It's self-evident that a tyre with less tread will disperse less water. The legal minimum is just that, a legal minimum, but obviously there is a physical limit to the amount of water that will be dispersed and that is dependent on the tread volume. Again, blindingly obvious. The effect of large tread blocks on dry grip is a converse matter.

Then the second question ... say you've got newish tyres on the front and something close to the legal minimum on the back, and it's a very wet summer day. The problem you have starts when the back starts to slide, irrespective of whether the car is fwd or rwd. If the back does start sliding then it tends to go very quickly and with little warning, so if you're a driving god then you'll do fine.

I completely contest that - the rears on most cars will let go progressively, and when they do, you can still steer the car as well as take the appropriate action to control it. It's nothing to do with being a "driving god", you can get a car VERY sideways and still get it back safely and in a controlled manner if you do the right things, and it's not rocket science doing them.

The only way to stay safe for the average driver is to drive significantly slower, perhaps even stop until the rain eases and the water begins to drain away, but there's nothing to tell them how much slower is safe.

Of course there is, there is feel through both the steering and the way the rear of the car is behaving, plus experience (which can only be gained in practice). It's not a sixth sense, it's paying attention to what's going on with the car, and learning how that feels, plus how things feel on the way to losing grip completely; it's not a binary issue, it's progressive. Driving slower is obviously a good idea, up to a point, but being able to tell how much grip your car has is something that very few drivers seem to bother to do, or pay any attention to, and that's the difference between sliding off the road and into a tree/bush/car/pedestrian and happily getting about; this is true whether the surface is ice, gravel, dry or wet tarmac or whatever.

On the other hand if the rear tyres are better at dispersing standing water then the limit of grip is at the front, and it's fairly easy to feel when grip at the front starts to go and just ease off the throttle to recover.

But you've painted an idealised picture there - most people don't lose grip because they are accelerating (and even if they do, unless there is ice then it's not a problem as the car will still mostly tend towards a tangential path to the intended direction of travel), they do so because they want to steer the car or brake. In such a situation then clearly letting off the throttle isn't an issue, and getting more front grip is because the front wheels control the car's direction, as well as doing the majority of braking. The rears do not. I'm quite handy on the bar, and was having a good play yesterday, but the laws of physics have control, and there's no way to steer the car from the rear; you can alter what it is doing by the way you drive and the way you alter the grip between front and rear (i.e. you can initiate a drift by losing grip at the rear, and also you can trim the car's attitude into a corner as well, reducing the lateral effect of understeer), but you can't make the back go in a different direction to the one the forces being applied to it are making it go.

I expect it's similar when driving on slippery winter surfaces.

The game remains the same regardless of the surface in use, it's just that the speed/force at which things start to happen decreases. The problem is a lack of driving ability (not natural ability, but practice and paying some attention to your ability as a driver) combined with the 'natural' tendency to press the brake pedal harder when the front locks up. In addition poor advice given by 'experts' leads to bigger issues, compounded with people thinking that more throttle is a better thing when traction is lacking, and so on. The way the wheels fall off the friction curve as soon as they lock makes a massive difference.

Bottom line - more grip at the front, and learn to drive half-decently, and all will be well. Grip at the rear isn't what you want, as it means the weakest part of the car is the one you need to be able to control it.

[AnotherGareth]

Bottom line - more grip at the front, and learn to drive half-decently, and all will be well.

Expecting that from anything other than a vanishingly small minority of drivers is excessively optimistic.

[RobinSLXi]

On the other hand if the rear tyres are better at dispersing standing water then the limit of grip is at the front, and it's fairly easy to feel when grip at the front starts to go and just ease off the throttle to recover.

If anybody's getting throttle-induced wheelspin on the public road other than occasionally when pulling away from a standstill, they should stop driving like a tit. If however you simply reach the limit of lateral grip whilst cornering, easing off the throttle in a FWD car is the best way to get personal with the hedge. What you need in that situation is enough traction such that opening the throttle pulls the car into line. The rear tyres in this situation are pretty much irrelevant. And of course, even if you're not understeering then backing off mid-corner still isn't the greatest idea if you can avoid it. In short, FWD cars need to pull themselves round corners, so you want grip on the wheels that both steer and drive

Remember ABS wasn't invented to improve braking performance, its purpose has always been to prevent loss of control whilst braking, and that control depends primarily on the front tyres gripping the road so you can steer.

I expect it's similar when driving on slippery winter surfaces.

Well, as I've experienced such conditions several times in FWD cars with 4 good tyres, let me enlighten you. Yes, it's easy to feel when you lose grip at the front - it's not much use though because by then there's nothing you can do except let go of everything, steer straight-ish and hope the wheels hook up again before you run out of road. I've only once had the back end go coming off a mid-corner bump on an icy road at about 40mph (one I would normally take quite happily at 60, I add), and it doesn't really matter what rear tyres you have if one of them's got virtually no weight on it and the other's on black ice. As the 'steer into it and hope' approach kept the car on the tarmac (thankfully nothing coming the other way), may I claim my 'driving god' badge?

Edited 20 December, 2010 by RobinSLXi

[AnotherGareth]

If anybody's getting throttle-induced wheelspin on the public road other than occasionally when pulling away from a standstill, they should stop driving like a tit.

I don't think I mentioned pulling away from a standstill - losing front end grip can easily happen at a steady speed as the road surface changes from less slippery to more slippery.

If however you simply reach the limit of lateral grip whilst cornering, easing off the throttle in a FWD car is the best way to get personal with the hedge.

Easing off the throttle slightly is generally fine.

The problem is when people come off the throttle abruptly -- the reduction in back end grip is much greater than the increase in front end grip. While this is also true to some extent for easing off the throttle slightly, it generally doesn't require much of a lift to regain front end traction unless the corner entry speed was way too high.

The rear tyres in this situation are pretty much irrelevant.

On a fwd car the rear tyres are all that stops the car from spinning.

it doesn't really matter what rear tyres you have if one of them's got virtually no weight on it and the other's on black ice.

Winter tyres. And stop going into bends too quickly. HTH.

[djaychela]

Expecting that from anything other than a vanishingly small minority of drivers is excessively optimistic.

But again, you've missed the point. More grip at the front than the rear will help everyone, because that is how you steer the car - whether you are someone who passed your test last week, or you are Sébastien Loeb. An improvement in driving skill will make situations that are borderline or dangerous for a currently poor driver far safer, but they are separate issues. Cars need grip at the front because that's how you steer them, and how you deal with every situation that you will come across.

You're still talking about losing grip due to acceleration, and have said nothing about losing grip due to braking/steering forces being excessive. How do you suggest these are dealt with given that your advice has made it more likely to happen?

[RainbowFire]

Am kinda thinking that we're very much coming into two camps here....

1) Those who actually have proper experience of driving in the snow / messing around / pushing their vehicles (whatever they may be) to the limit and finding out what happens next. :-)

And

2) Those who have not and just believe what they have read somewhere. :-)

-------------------------------------------------------------

Back in the dim and distant past "Drive And Survive" used to use a Mondeo fitted with an extra wheel at each corner. These wheels worked independantly and would lift that corner of the car. You could lift one corner, one end or one side. Apparently you can simulate any kind of wethered road surface using this, including different ones front and back.

Lifting the back did give a certain loss of control, but not complete loss as the front wheels still had contact. You could still heavily influence the car.

Lifting the front instantly meant you became a passenger to physics (again physics plays it's role). No matter what you did, the only thing you could do with the rear wheels was brake. Even if the ABS kicked in, it was useless as the front wheels had no traction.

Those were the days

Alex

[RainbowFire]

(Seem to have broken the quote thingy)

"I don't think I mentioned pulling away from a standstill - losing front end grip can easily happen at a steady speed as the road surface changes from less slippery to more slippery."

I don't think Robin said you did. However, a change in surface won't automatically make the car change direction. If you drive from tarmac on to ice, the car will continue along the same trajectory as it was when it hit the ice. (Again with the physics) The problem comes when you want to change that, e.g a bend in the road.

"The problem is when people come off the throttle abruptly -- the reduction in back end grip is much greater than the increase in front end grip. While this is also true to some extent for easing off the throttle slightly, it generally doesn't require much of a lift to regain front end traction unless the corner entry speed was way too high."

Ah, but for the "normal" driver, not doing things abruptly but doing them carefully and gently is the role of your "driving god".

"On a fwd car the rear tyres are all that stops the car from spinning."

Only if you have already applied a lateral force to them, for example, from the front wheels turning. Otherwise they are there to hold the back of the car up. (It's a car not a helicopter, there are no natural lateral forces being applied that need counteracting)

If you want to try and see if you can get the back go first, get a pickup. We have no weight in the back. With no load, the back is just for show. So far, all Thunderbird 4 has done is understeer.

Alex

Edited 20 December, 2010 by RainbowFore

[RobinSLXi]

I don't think I mentioned pulling away from a standstill - losing front end grip can easily happen at a steady speed as the road surface changes from less slippery to more slippery.

You didn't. You mentioned as you have again now, a loss of grip travelling in a straight line. If you lose front end grip whilst cornering, the mass of the car will simply try to continue in the direction of its momentum, and the rear wheels will happily be pulled along behind that centre of mass with effectively no lateral forces acting on them, being not much use - they could in theory provide a degree of braking force, but if you hit the brakes you will completely lock up the sliding front wheels and lose any hope of control.

Easing off the throttle slightly is generally fine.

Having half-worn-out cheap rubbish tyres is generally fine, too. Still isn't the best idea though.

The problem is when people come off the throttle abruptly -- the reduction in back end grip is much greater than the increase in front end grip. While this is also true to some extent for easing off the throttle slightly, it generally doesn't require much of a lift to regain front end traction unless the corner entry speed was way too high.

Yes, but assuming we have more grip at the back to start with as you advocate,it's going to be very difficult, regardless of entry speed, to transfer enough weight forward for the rear tyres to break free without overwhelming the front tyres - so we still understeer off the road instead of spinning.

On a fwd car the rear tyres are all that stops the car from spinning.

Let me say the same thing for about the fourth time in yet another slightly different way. In the situation to which you are referring having quoted me, i.e. the front wheels have lost grip first, there is nothing to apply lateral force and induce a turning moment upon the mass of the car - the mass will now also be pivoting about the rear axle rather than the front, so any remaining rotational momentum will cancel itself and the only force acting on the car is its remaining forward momentum which is acting in the current direction of travel. Thus the rear tyres will roll along happily in that straight line with traction to spare, being redundant as I explained above. We could pull the handbrake as a token gesture, but it will barely slow us down before we run out of road, and at worst could lock the rear wheels too.

Yes, if a driver doesn't know what to do in that situation and applies more lock instead of straightening up, there is a small chance the front tyres could hook up again and potentially flip the back around, but then the right conditions for that just aren't going to be there for someone driving normally on the public road. Besides, a driver who doesn't know what to do in that situation will stamp on the brakes 99% of the time anyway, thus skidding off the road in a straight line once again.

Winter tyres. And stop going into bends too quickly. HTH.

And I'm glad for the help - please do tell me where I can buy winter tyres with so much grip that one of them can suddenly perform as well on black ice as two all-year tyres would on cold tarmac - I hope I can afford some. Remember studs aren't road legal and nobody makes F1 qualifying compounds that fit a Mondeo. And since I can't judge corner entry speeds, here you go - you're travelling southbound. It's a fast, fairly wide and open B-road, very little traffic, typically doing 50-60mph around there, and at that speed in the dry you barely notice it's a bend. It's dark and you would see any oncoming headlights in plenty of time. You've not seen any ice so far but you know it's -4 so you're driving carefully and a fair bit slower than usual, even though you drive this road at least twice a day. If nearly half the usual speed is too fast, how fast should I be taking it?. Remember that to potter round left-handers at 10 mph runs you the risk of being rear-ended by someone who can't see you in time due to the hedge.

I only mentioned that as an example of the kind of extreme situation - back end goes light and loses grip as it bounces over a bump - that's likely to catch a normal driver out. Except in a one-off like that, a typical driver in a FWD family hatchback will just never experience snap oversteer, especially on the public road. And if anybody wants to argue against that, could they please arm themselves with a demonstrable understanding of physics and/or car handling dynamics first? Ta.

[Richard Black]

I don't see any mention on this thread of one rather interesting distinction between the sort of treads normally fitted to Felicia-type cars and those on fast Beemers etc - the latter may be 'summer' tyres but the relatively skinny, low-performance ones on a Felly (etc.) are typically rated as 'all weather'. That's not to say they are as good as M+S treads in really dreadful conditions (er, like right now) but they aren't too bad - and would be legal in countries where summer treads are banned in winter months.

As for front versus rear, I tend to run different sizes and types front and rear (my Favorit has 185/55/14 front and 165/70/13 rear - same rolling radius so I can in a pinch use just the one spare on either axle to limp to the nearest repair shop). This is most certainly not illegal and most performance cars (and the Smart!) have different front and rear specs as standard. Putting winter treads on the front will improve things considerably: putting them on the back as well may slightly aid matters but the bottom line is that if they're on the front you'll be able to get out of trouble in ways that will defeat most drivers in most cars. Unless you're intending to leather it to the max in the snow, putting them on the back of a Felly (etc.) is ornamental.

[AnotherGareth]

please do tell me where I can buy winter tyres with so much grip that one of them can suddenly perform as well on black ice as two all-year tyres would on cold tarmac

You've probably left it too late this year ;-)

Last winter, between Christmas and New Year, I went to a track day. Foolishly, as it turned out, I used my winter tyres. Vredestein Snowtrac 3 if you're interested. We were told that there were patches of ice on the track, and during the morning a number of drivers reported having issues through and out of the chicanes but I didn't notice any significant problems at all.

The foolish aspect was that I used a fair bit of the tread during the day, but the wise aspect was driving to the track at Bruntingthorpe from east Berkshire very early in the morning on icy roads, as I didn't notice anything out of the ordinary although my friends who were using normal tyres all complained of treacherous conditions.

I hope you agree that having four tyres the same and in good condition was a sensible precaution for what I was planning to do. It's a shame I've not arranged to go this year :(

Regarding your road south of Cambridge; it's exactly for these unusual situations that people fit winter tyres all around, and try to ensure that the grip at the back is likely to at least be as good as the grip at the front.

Edited 21 December, 2010 by AnotherGareth

[djaychela]

You've still not answered my question....

[AnotherGareth]

More grip at the front than the rear will help everyone, because that is how you steer the car

It's OK until you get into the sort of unforeseen situations that the recommendation is designed to help with.

You're still talking about losing grip due to acceleration, and have said nothing about losing grip due to braking/steering forces being excessive. How do you suggest these are dealt with given that your advice has made it more likely to happen?

I was talking about losing grip when maintaining a steady speed. I accept there are other cases as well. My advice is to have 4 matching tyres that are appropriate for the conditions. If people choose to do something else, that's their choice and their risk.

Edited to add: just had a look at the car handbook (to find about tyre sizes compatible with snow chains). The following caught my eye: "In winter conditions, winter tyres will significantly improve the handling of your car. [...] To achieve the best possible handling and grip, fit winter tyres to all four wheels (same manufacturer, tyre size, tread pattern)".

Edited 21 December, 2010 by AnotherGareth

[Pell]

Just thought I'd give my thoughts, I live in Norway and have been driving on snow and ice for half the year, every year since 1997.

The roads here are very slippery, and if I were to use only two winter tyres I'd have to decide between two types of handling:

Having the winter tyres at the front of an FWD will of course give the best steering response, and going uphill is easier.

The downsides are that the back comes out when cornering, and also while straight-line braking (or braking while going down a steep hill) because the rear wheels may lock up while your front tyres don't. The locked wheels will then try to "overtake" the front set of tyres that still have some resistance, so the car will go sideways or spin.

Going sideways obviously increases the chance of colliding with oncoming traffic, and in a small tin can like the Felly you really don't want to hit anything sideways. Not very safe at all.

As for putting the summer pair at the front, even worse idea. The car will understeer, and of course it will be wheelspin mania. It will brake straight but the stopping length will be very long.

So really, having winter tyres at one end and summer tyres at the other is a pretty bad idea either way.

However, if you have:

a ) A full set of winter tyres where one pair has significantly less tread than the other pair

b ) One pair of proper winter tyres and one pair of mud&snow or year-round rubber,

it comes more or less down to personal preference. The choice will affect the handling as I described above, but not as severely.

My Felly has studded tyres, but there are no studs left at the rear (cause they used to be at the front . Since the car is inherently a little understeered, having the best wheels at the front actually balances the car out quite well. It only oversteers on ice and hard-packed "polished" snow, and only if I turn very quickly.

I may be stating the obvious here, I don't know how much you guys drive in really slippery conditions, but I still hope someone finds it informing.

Edited 21 December, 2010 by Pell

[swedishskoda]

^^ Very well put

...I don't know how much you guys drive in really slippery conditions...

Right now most UK drivers do, or so it seems... but it is obious, from other threads, that most people over there rarely use winter tyres and therefore haven't seen the point in getting any (those that have have on the other hand testified about the great difference).

In Sweden the law (and not without reason) requires the same type of tyres on all four wheels - e.g. 4 M+S or 4 studded (although you can probably get away with 2 tyres that were once studded even if most of the studs have fallen off).

Edited 21 December, 2010 by swedishskoda

[djaychela]

I was talking about losing grip when maintaining a steady speed.

Which happens almost never. Nearly everyone who has a prang in this sort of weather will do so because they've lost front grip, been unable to stop/steer and hit something they've seen coming for some time.

I accept there are other cases as well. My advice is to have 4 matching tyres that are appropriate for the conditions. If people choose to do something else, that's their choice and their risk.

There are other cases, and they are the majority. Obviously again, but that's not what was asked, and the advice that having more grip at the back is simply dangerous, IMO.

Edited to add: just had a look at the car handbook (to find about tyre sizes compatible with snow chains). The following caught my eye: "In winter conditions, winter tyres will significantly improve the handling of your car. [...] To achieve the best possible handling and grip, fit winter tyres to all four wheels (same manufacturer, tyre size, tread pattern)".

Again, that's obviously true, but if you're only going to have two, then the front is the best place to have the grip.

[RainbowFire]

In Sweden the law (and not without reason) requires the same type of tyres on all four wheels - e.g. 4 M+S or 4 studded (although you can probably get away with 2 tyres that were once studded even if most of the studs have fallen off).

I suspect, possibly, that the "4 wheel law" is to allow for those who don't know if their car is FWD, RWD or 4WD, so you're forced to take the most sensible option, which is not so bad I supose. (Mind you, I supose we're into "nanny state" terratory there) ;-) ;-)

Alex