2 or 4 Winter Tyres

clever_username

Talk about over-thinking a problem...

liquidbutindebt

Newton's second law is fundamental. Friction is simply an effect on a force that must be accounted for when applying Newton's laws. Anyone who has studied basic mechanics in maths at school should know this stuff. Of course, there are other factors at work, as a car is clearly a more complex "system" than a block moving down a slope (as is typical in simple maths problems). But the fundamentals to understanding why the rear of a car is far less stable than the front when you have a massive friction differential between the two tyre contact points are fairly simple.

Pew_Pew_Pew_Lasers!

I'd not bother liquid, many of these people don't even understand why putting new tyres on the rear axle of a car is safer than putting them on the front.

C_Crawford

Pew_Pew_Pew_Lasers! wrote: »

I'd not bother liquid, many of these people don't even understand why putting new tyres on the rear axle of a car is safer than putting them on the front.

I actually wonder how many people drive for a living and have actually driven on snow and ice regularly.
I did it last year in a Variety of vehicles and I am indeed doing this year. I find the grip in fresh snow to be ok but compacted snow is the problem. I also can tell you no matter what tyres you have winter or summer if you brake hard you will go straight on, this also applies to turning. I have never once seen the rear of a car jump out to the side at 20-30mph under heavy braking in a modern car. You really shouldn't be driving at any kind of speeds in bad weather anyway.
I never use the accelarator just the clutch and sit in 2nd or 3rd, approaching junctions I just change down and only use the brakes at 5mph or under. I have been driving for 25yrs and had one accident when I was 21, I aquaplained off the road.
This taught me a lot and made me go to race tracks to learn car control. I am a very deffensive driver but here comes the problem, If I have winter tyres and do an emergency stop the person behind me who was too close in the first place with rubbish remoulds is going to rear end me. So having only 2 winter tyres on the front of my car will be the least of my Worries I would think.
All I want to do is get up the hills to my house, I cannot walk this route as it takes me through a well known housing estate where I am not popular due to my job with the local Authority.
I cannot afford 4 winter tyres at this time but hope to buy another 2 next year. Now time for everyone to CHILL and Merry Christmas to you all. xXx

C_Crawford

Thought I'd follow up on my last post with an honest Review of Goodyear UltraGrip 7+ Fitted to the front of my 07 Focus TDCI.
First off I'd like to say these tyres are amazing, I can stop on a steep snow covered road and pull away again. I can pull out of junctions in Snow, slush and icy conditions without wheelspinning on the spot. I can also stop quicker than I ever imagined in these conditions. There was a lot of talk of the car being undrivable in snowy icy conditions etc so here are my honest opininons on this.
I took the car out to a large retail car park (after hours and empty) that was covered in snow and tried a variety of tests with the Maximum speed being 30mph.
First test emergency stop in a straight line, Car stopped fine, rear end did not come round.
Emergency stop whilst cornering, same result as above.
Emergency stop whilst pulling hard on the wheel to one side, same result as above.
Then it gets interesting cornering at a normal speed,whilst being carefull was fine.
Cornering slightly too fast and I do mean slighty, just starting to feel understeer and lifting off = Back of the car comes violently out of line. For normal drivers I feel this might be too much for them to catch or control on a busy road. I explained my reasons in an earlier post for only buying 2 tyres for the front but my circumstances are different to most others.
There was some confusion regarding what I was talking about with modern ABS whilst braking hard, most thought the back end would come round and I said otherwise. This is still the case, I have even tried an emergency stop going down the hill from my house to no avail. Even turning left down hill and braking hard the car remained stable. My View on this is modern ABS is amazing, my car has discs all round and when I brake the noise is frightning as the brakes come on and off from all the wheels stopping the car.
So to Summarise, if you travel any distance greater than 1 Mile and are likely to come across snow. slush, ice etc and are thinking of buying winter tyres then I'd highly recommend you get them as they are amazing in what they do.
What I can't recommend is buying 2 tyres, I would love to say otherwise but as other posters have said and I now have to agree with them is if you don't kill yourself you will scare yourself senseless.

PS: My partner was so impressed & scared of the difference these tyres make that she has allowed me to order 2 tyres for the rear from our savings. The reason being is she would actually drive in the snow herself, something she has never done before due to us living on a hill.
I hope this was helpfull to those thinking about buying winter tyres. I was hoping to film my tests but have not had the time as yet. If I can manage I will do so before I fit the rears and post on youtube.

Regards,

Charly.

peterbaker

Charly, a very useful post indeed.

I have had experience of both winter tyres and summer tyres in this big freeze.

I agree with all you say. Winter tyres are a considerable antidote to the loss of traction we all get on summer tyres, but when it comes to stopping they are sure-footed whereas summer tyres are a complete lottery, but above all the ABS systems are the ultimate back up even on small cars (I have been driving an A6 and a Punto). The Punto had its 4 winter tyres (and wheels) on it 2 weeks before the snow.

The A6 is a low revving diesel but I also tested it in an empty retail car park on summer tyres - embarassing how easily you can lose total directional control without accelerating and steering extremely aggressively like a demented rally driver. The ABS limits embarassment slightly but not much once you have a ton and a half intent on a particular direction.

In the Punto, the winter tyres give great confidence and so long as one realises that there must be a limit, then they are surely the safe way to go. The ABS acts as a complimentary backstop should you slightly overstep the mark with late braking on winter tyres, but as Charly says, in corners you are still in the lap of the laws of physics. Winter tyres or not, they will let go at some point and you'd better know how to deal with that or drive much slower.

Overall, whatever you are on, KNOW YOUR LIMITS, and you can't possibly know unless you have tested them safely like C Crawford or been up in the Welsh Mountains for half a day with Jan Churchill or someone like that - Now I am showing my age

mikey72

C_Crawford wrote: »

First test emergency stop in a straight line, Car stopped fine, rear end did not come round.
Emergency stop whilst cornering, same result as above.
Emergency stop whilst pulling hard on the wheel to one side, same result as above.
Then it gets interesting cornering at a normal speed,whilst being carefull was fine.
Cornering slightly too fast and I do mean slighty, just starting to feel understeer and lifting off = Back of the car comes violently out of line.

Sounds about the same as my experiences.
I tested mine with 2 winter and 2 summer tyres. As you say, normally good. I haven't managed to get the back round without using the handbrake though.
I suppose if you are cornering fast enough for the front to break away, even on winter tyres, with summer tyres you would have been long gone into a ditch, so I wouldn't disagree with that either.
I think if you have two winter tyres, but drive like you are on four summer tyres, you'll be safer. Still no doubt 4 winter are better though. And 4 summer tyres are worse than 2.

Pew_Pew_Pew_Lasers!

Thanks for the update C Crawford, an interesting read and I mean that sincerely.

bigjl

Not sure why anybody would expect a FWD drive car to behave in any other way than you experienced when lifting off suddenly when the car was beginning to understeer, this is called lift off oversteer, and anybody that drove an old Peugeot will know all about it.

In your situation your own posts show that when driven as you would normally the rear didn't step out, however you then pushed the front end, with winter tyres on, until they exceeded available grip, lifted off and experienced lift off oversteer.

I suggest you try the same thing in the wet with your normal tyres on, turn until you feel the front start to understeer, then lift off suddenly, you will then experience the same thing, especially since the Focus is well known to have this handling trait.

As you stated it was only this harsh treatment that caused the oversteer, it would have been exagerated by the relative difference in grip available, but not by as much as you may think.


Lets face facts here, after 5 or 6 thousand miles on a FWD car the rear tyres have more grip than the fronts due to the different levels of wear, this doesn't make the car unsafe, as any driver regardless of experience will have adjusted to the change in grip levels as it occured, unless you go out any check tread depths every 100 miles and then swap front to back etc then almost every FWD car on the road has slightly more grip on the back than the front.

As mikey has said the best case scenario is 4 winter tyres, but 2 winter tyres aren't dangerous, as Charley has proved.

There is little if any difference with winter tyres on the front and snow socks on the front.

Winter tyres and snowsocks are a good way to get extra traction, not turn your car into a rally weapon that can't be crashed.

If you have ever seen Ice Road Truckers you will see that they only seem to chain up one axle of the driven wheels, the ones that have the best traction, and since these people drive in Alaska and Canada in conditions much, much worse than we have ever seen in the UK then I reckon they know more than anybody in the UK.

As most of the congestion over these few weeks of snow have been due to loss of traction, how much less would it have been with winter tyres on the driven wheels? I reckon substantially less.

Note that when I mention snowsocks on the front of FWD vehicles only that was the advise given by the LAS lastyear, and the fleet department would have consulted Vauxhall and GoodYear (the tyre supplier until early 2010) aswell as the makers of snowsocks.

I personally didn't bother, some Ambulances had them on the rear outside wheels only, they gave extra traction but where more of a pain than anything else, as soon as you drove on cleared roads they needed to be removed or got ripped to shreads.

SHIPSHAPE

vaio wrote: »

Energy Saving and winter tyre levels of grip? If anyone could make single tyre that had both then they would corner the market

Why not properly read what I wrote?

A premium tyre like Michelin ES perform outstandingly well in the wet, dry, cold etc in all tests that are performed to rate a tyre.

A winter tyre only differs due to their compound which only comes into effect at -7 and below.

Considering the coldest December for 100 years has just passed where the average temp for the month wasn't even -1 then what I originally stated is true.

One is better off buying premium tyres, even for the winter, than buying specifically winter tyres in the UK.