4wd or winter tyres, which is better?
Discussion
Ok, bit of a click-bait title.
I'm a strong believer in the right tyres for the job. So if you live somewhere and drive at times when winter tyres would be sensible, then I'm all for it, regardless of how many driven wheels your vehicle has.
What I can't get over however is, the claims people make about 4wd's being useless in the snow. Such as can't stop and can't corner. And the blatant ignorance that a 2wd car on winter tyres is the ultimate answer.
Here is a little vid from last Dec with some nicely snowy roads. Neither vehicle is equipped with winter tyres (although the tyres are in my opinion still suitable for the task at hand).
Plenty of other 4wd's about in the footage too and lots of stranded, stuck or abandoned 2wd cars. Not sure were all the winter tyre advocates were on this day. They must have either been at home or stuck somewhere as I didn't really see any out and about. I also didn't really see any stuck, crashed or abandoned 4wd's either, well apart from one BMW...
https://youtu.be/V8tNckpZSWE
The point here is not to say if one is better than they other. Just that 4wd can and does give an immense advantage in such conditions, that you may feel happy enough that you can remain mobile in such conditions. Obviously not all 4wd's are equal and summer performance tyres on an AWD saloon/coupe are going to be quite different to off road tyres on a 4x4.
However if winter mobility concerns you, maybe running a 4wd is an option you might want to consider.
I'm a strong believer in the right tyres for the job. So if you live somewhere and drive at times when winter tyres would be sensible, then I'm all for it, regardless of how many driven wheels your vehicle has.
What I can't get over however is, the claims people make about 4wd's being useless in the snow. Such as can't stop and can't corner. And the blatant ignorance that a 2wd car on winter tyres is the ultimate answer.
Here is a little vid from last Dec with some nicely snowy roads. Neither vehicle is equipped with winter tyres (although the tyres are in my opinion still suitable for the task at hand).
Plenty of other 4wd's about in the footage too and lots of stranded, stuck or abandoned 2wd cars. Not sure were all the winter tyre advocates were on this day. They must have either been at home or stuck somewhere as I didn't really see any out and about. I also didn't really see any stuck, crashed or abandoned 4wd's either, well apart from one BMW...
https://youtu.be/V8tNckpZSWE
The point here is not to say if one is better than they other. Just that 4wd can and does give an immense advantage in such conditions, that you may feel happy enough that you can remain mobile in such conditions. Obviously not all 4wd's are equal and summer performance tyres on an AWD saloon/coupe are going to be quite different to off road tyres on a 4x4.
However if winter mobility concerns you, maybe running a 4wd is an option you might want to consider.
thiscocks said:
Finlandia said:
The only adjustment I would make to that list is that a FWD car on winter tyres is better than a RWD car on winter tyres, simply for the reason that when you get stuck you can wiggle your way out by turning the driven wheels to find grip.
And there is normally more weight over the FWD cars tyres compared to RWD.Finlandia said:
It can also be argued that a 4wd car on summer tyres is more dangerous than a 2wd car on same tyres, they are easier to get up to speed but stopping is as difficult as a 2wd car.
If you have full time 4WD surely it will brake a bit better having engine braking on all four wheels as opposed to just 2? jon- said:
I did this very test earlier this year, the video will be out on the channel in a week or so. Two matching BMW X1's, one with FWD and winter tyres, one with 4WD and summer tyres.
You can guess which one was comically bad.
So why no 4wd on winters...... that is the real question surely? Nobody really actually asks what you have done.You can guess which one was comically bad.
Finlandia said:
No AWD will save that.
On ice and snow you need tyres with better grip, not more driven wheels without grip.
You seem to be consistently missing the point, a real shame.On ice and snow you need tyres with better grip, not more driven wheels without grip.
Firstly truly icy roads in the UK, at least from the Midlands down, are rare. As we have very few days that remain below freezing. The same is true for snow, it is incredibly rare to get fresh snowfall on top of old snow. So most snow we drive on is fresh, not heavily compacted and re-frozen.
As for the braking, and as discussed previously. This is not in regard to foot flat to the floor on the brake pedal emergency stopping. This is about normal driving, which requires controlled slowing and decreasing of speed for corners, junctions, traffic etc.
For this, the use of engine braking an AWD massively reduces lock up and sliding on slippery surfaces. And is far more effective than simply using the ABS and the brake pedal. If you have no practical experience of this, then I highly recommend seeking some, or some additional driving training.
Driving off road on slippery surfaces is very similar in many regards. And is the reason why you'd opt for 4wd to descend a slippery slope, rather than use 2wd and the brake pedal.
jagnet said:
300bhp/ton said:
For this, the use of engine braking an AWD massively reduces lock up and sliding on slippery surfaces.
Judging by the moment at 18:10 in your video, you may want to tell the driver of the lead vehicle about that benefit.This technique also works very well in stubble fields at harvest, where the surface is also soft and slippery.
This point of the vid also shows the benefit of 4wd vs 2wd on the same tyres. I wasn't sure how solid the bank was when I went round the van. So I put the Land Rover into low range for more control, once past the van I went back to high range, however how the selectors work in a Series Land Rover, when you go form low to high ranges, it automatically puts it in 2wd. So you'll see there is a bit of tail sliding and wheelspin until I re-en-gauge 4wd.
https://youtu.be/V8tNckpZSWE?t=1107
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
jagnet said:
You are delusional if you think sliding sideways towards another vehicle when stopping from 15mph is a good thing and somehow proof of 4WD's advantages.
Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
Maybe you should try providing some actual evidence and first hand accounts then? You seem rather light on substance, yet quick and willing to hand out derogatory insults.Any winter tyre equipped vehicle would've stopped without drama in that situation. No sliding, no need to build up snow in front of the tyres, no ABS involvement, no need for AWD.
RicksAlfas said:
Thanks for the link 300bhp.
His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
Hi, I put an explanation in the Winter Tyres thread.His explanation was that the brake bias is different when he engages four wheel drive. I don't understand why that would be. Brake proportioning valves on road cars are usually dependant on brake pressure and the amount of load in the car. Not which wheels are being driven. It's how they determine whether it is just Kylie driving in her undies, or four prop forwards with a boot full of bricks. Can anyone technical explain why would brake bias differ when he engages four wheel drive over rear wheel drive?
You say his explanation is why it works with engine braking too. Engine braking has nothing to do with brake bias, so I am further confused but ready for someone to explain it please.
I'm more enthusiast than outright engineer, so this is my take on it. But I'm reasonably certain I'm on the right track.
300bhp/ton said:
Normal road cars normally have a brake bias with 70+% to the front. Because on grippy tarmac when you brake you get a lot of weight transfer to the front. In slippery conditions you will not get the same weight transfer, as you won't generate enough grip on the front wheels. The aim of the heavy front bias is simple, under hard braking you want all the wheels to lock up at about the same time, the fronts slightly before the rears. Due to the weight transfer under braking, the fronts need to work a lot hard to lock the tyres up/induce ABS.
You can see how much the nose dives under braking, even on a car with stiff suspension:
But the heavy front brake bias means, when on a slippery surface that the front wheels will lock up/induce ABS much sooner and earlier on with a lot less braking effort. This is simply because you aren't getting the weight transfer on a slippery surface. When this happens it will reduce your rear braking effort, especially if equipped with ABS, where it will kick the ABS in and further reduce braking forces. The rear brakes are being highly under utilised, as you never get to brake hard enough to make them work to their full extent in these conditions. And the crux is, the rears probably won't be at the point of lock up or inducing the ABS under these conditions, meaning they could have helped brake and slow you more so.
On a slippery surface you want a more even front to rear brake bias (nearer to 50:50), so that all the wheels want to lock at the same time (50:50 bias would be bad on a dry tarmac roads, as the weight transfer under braking to the front on grippy surfaces would make the rears lock up before the fronts, causing you to spin). Hence why there is a front bias for the brakes as standard.
By locking the front and rear props together with a 4wd system (and centre diff lock if equipped). It effectively means that the rear wheels will have the same brake bias as the fronts, as some braking will be coming from the prop, which directly joins the front and rear axles together.
The end result on a slippery surface is a vehicle able to apply more braking force in total before lockup and less chance of kicking in the ABS. Hence why it will stop quicker (shorter distance). As demonstrated repeatedly in the video.
Cars with open centre differentials such as late model Jaguar X-Types will see no benefit at all, as the front and rear axles aren't directly joined or turning at the same speed. A Land Rover Defender with the centre diff lock open would also not benefit, but it would when the centre diff lock is engaged.
Limited slip centre diffs will see some benefit, but not as much as a directly linked setup.
You can see how much the nose dives under braking, even on a car with stiff suspension:
But the heavy front brake bias means, when on a slippery surface that the front wheels will lock up/induce ABS much sooner and earlier on with a lot less braking effort. This is simply because you aren't getting the weight transfer on a slippery surface. When this happens it will reduce your rear braking effort, especially if equipped with ABS, where it will kick the ABS in and further reduce braking forces. The rear brakes are being highly under utilised, as you never get to brake hard enough to make them work to their full extent in these conditions. And the crux is, the rears probably won't be at the point of lock up or inducing the ABS under these conditions, meaning they could have helped brake and slow you more so.
On a slippery surface you want a more even front to rear brake bias (nearer to 50:50), so that all the wheels want to lock at the same time (50:50 bias would be bad on a dry tarmac roads, as the weight transfer under braking to the front on grippy surfaces would make the rears lock up before the fronts, causing you to spin). Hence why there is a front bias for the brakes as standard.
By locking the front and rear props together with a 4wd system (and centre diff lock if equipped). It effectively means that the rear wheels will have the same brake bias as the fronts, as some braking will be coming from the prop, which directly joins the front and rear axles together.
The end result on a slippery surface is a vehicle able to apply more braking force in total before lockup and less chance of kicking in the ABS. Hence why it will stop quicker (shorter distance). As demonstrated repeatedly in the video.
Cars with open centre differentials such as late model Jaguar X-Types will see no benefit at all, as the front and rear axles aren't directly joined or turning at the same speed. A Land Rover Defender with the centre diff lock open would also not benefit, but it would when the centre diff lock is engaged.
Limited slip centre diffs will see some benefit, but not as much as a directly linked setup.
Onehp said:
300bhp/ton said:
I posted this in the winter tyres thread, but some of you may have not seen it, so I'll post it here.
This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Unless you drive a pick-up with a transfer case and an archaic abs system with shot/seized rear brakes, this vid is totally irrelevant. Any well controlled rear braking system will easily provide all the braking retardation the grip at offer can provide. This is from a rally channel on YouTube. Video demonstrating how 4wd will brake better than 2wd on the snow:
https://www.youtube.com/watch?v=8bXdXRbc2Rc&fe...
The technical explanation is at the end of the vid. But it's the same reason why engine braking with a 4wd works so well in slippery conditions.
Engine braking is also totally irrelevant for safe braking, unless you are going 90 degrees sideways and coming off the trottle at that point... At which point most people will disagree that your driving style is anywhere near 'safe'...
As I wrote somewhere before on this forum, actually 4wd is a risk factor as you will gather speed quicker and will notice a reduced grip situation much later, given that braking grip is naught better 99, 9987% of the time. With the same reasoning, rwd and summer tyres are by far the best, as on snow you won't be able to leave your driveway and won't be able to crash at any significant speed. Unless you glide out uncontrollable onto the lower lying street and someone comes driving on the 4wd summer tyred car at about the same time...
Your last paragraph
Finlandia said:
I live up in the Nordic region and have driven all sorts of 2wd and 4wd cars with or without winter tyres, winter tyres are a must on snow and ice, nothing beats them for stopping power and steering response, simple as that.
This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
Have I ever climed any different? Stop arguing something that isn't in debate. This is backed up by pretty much every tyre manufacturer, car manufacturer, car journalist and everyone who has tried winter tyres in winter conditions, not to mention the legislation in many countries where snow is an everyday thing during the year.
jagnet said:
You want video evidence of a 2wd car on winter tyres managing to brake to a standstill in snow, without drama, from 15mph?
How about this: https://youtu.be/hy3FUOHP434 downhill on a ski slope. Tiny bit of abs at one point just before coming to a stop but forgiveable as it's a frelling ski slope! A little tougher than conditions in your video but no need for diff locks, engine braking on the rear axle etc etc.
Plenty of other videos of 2wd cars managing to do the same on YouTube.
What other evidence would you like? That anyone living in Sweden, Norway, Germany, Austria, Poland, Czech Republic, Slovakia etc etc manage it every day in winter when it snows? They're not heading out in their defenders, engaging diff locks and filming themselves trundling about at 15mph, they're just getting in their cars and driving to work like it's any another day.
I asked for your proof and experience. Not your YouTube searching skills of other people's experiences. How about this: https://youtu.be/hy3FUOHP434 downhill on a ski slope. Tiny bit of abs at one point just before coming to a stop but forgiveable as it's a frelling ski slope! A little tougher than conditions in your video but no need for diff locks, engine braking on the rear axle etc etc.
Plenty of other videos of 2wd cars managing to do the same on YouTube.
What other evidence would you like? That anyone living in Sweden, Norway, Germany, Austria, Poland, Czech Republic, Slovakia etc etc manage it every day in winter when it snows? They're not heading out in their defenders, engaging diff locks and filming themselves trundling about at 15mph, they're just getting in their cars and driving to work like it's any another day.
Have you driven on M&S MTs or ATs in such conditions? Have you driven different types of 4wd in such conditions? Have you used winter tyres in such conditions? And have you used 4wd on winter tyres?
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