4wd or winter tyres, which is better?
Discussion
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.
300bhp/ton said:
So why no 4wd on winters...... that is the real question surely? Nobody really actually asks what you have done.
Everyone who thinks they should buy a 4wd because it will be better in winter is effectively posing that question, by not considering that they'd be better to just keep what they have/buy what they want and put appropriate tyres on it.It would be interesting to have that extra layer of test, though, seeing how much benefit the 4wd has over 2wd if both are on winters, and how the difference between them compares to when they're both on the wrong tyres, but Jon's not got unlimited resources. It takes a fair amount of time/work (and expense) to make a good comparative test, so he's got to concentrate on the primary question.
300bhp - I fully understand that many off road vehicles have a low first gear, and many have a low range gearbox, but "normal" cars don't. An Audi A4 or BMW 3 series for example are offered in both two and four wheel drive options. The gear ratios in both are the same.
If there are two cars identical in every way except one is two wheel drive and one is four wheel drive, why do you think the four wheel drive one will have better engine braking?
If there are two cars identical in every way except one is two wheel drive and one is four wheel drive, why do you think the four wheel drive one will have better engine braking?
300bhp/ton said:
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.
I drive on snow and ice for a big part of the year and I know what is best suited for it.
RicksAlfas said:
300bhp - I fully understand that many off road vehicles have a low first gear, and many have a low range gearbox, but "normal" cars don't. An Audi A4 or BMW 3 series for example are offered in both two and four wheel drive options. The gear ratios in both are the same.
If there are two cars identical in every way except one is two wheel drive and one is four wheel drive, why do you think the four wheel drive one will have better engine braking?
He's not wrong, though, with drive to all four wheels, you can have more engine braking before the tyres lose grip, no different to accelerating really. It's not as common, but you definitely can have an issue with it in really slippery conditions, like coming down an icy hill. If there are two cars identical in every way except one is two wheel drive and one is four wheel drive, why do you think the four wheel drive one will have better engine braking?
He's also right about the mild anti-lock effect under gentle braking with 4wd, the threshold of how gentle you need to be to avoid locking a wheel can be a little higher.
I don't think this stuff outweighs just having winter tyres even on a 2WD car, but it is all "real".
Thanks Dave. I'm not saying he's wrong. 
I know 300bhp has a lot of 4x4 experience, but I'm just having trouble visualising engine braking making any difference between two and four wheel drive cars. It must be pretty marginal? In many cars the rear wheels are pretty lightly loaded and unless it's a permanent 4x4 system, one set of wheels might not be doing anything anyway?
I know 300bhp has a lot of 4x4 experience, but I'm just having trouble visualising engine braking making any difference between two and four wheel drive cars. It must be pretty marginal? In many cars the rear wheels are pretty lightly loaded and unless it's a permanent 4x4 system, one set of wheels might not be doing anything anyway?
RicksAlfas said:
If there are two cars identical in every way except one is two wheel drive and one is four wheel drive, why do you think the four wheel drive one will have better engine braking?
But this is NEVER the case. Let’s assume an Audi A4 FWD and then an a4 4WD. Two things to consider are a) the 4WD weighs more and therefore has more energy to slow/stop from any given speed and b) an A4 AWD is part-time 4WD and the 4WD only kicks in during acceleration not deceleration. An A6 is permanent 4WD so loses out on the weight side of things
However the majority of the British public consider a 4WD to be an SUV and wouldn’t consider a ‘saloon/estate’ car 4WD vehicle.
In the case of SUV’s vs similar size ‘normal’ cars, the weight difference can be vast and makes the ‘engine braking on all 4 wheels’ argument very weak.
I can accept engine braking off road when you’re facing a 1:1 descent but in the real world of roads and tarmac, it really makes no discernible difference hence people who live in the Alps and The Nordics mostly drive FWD cars fitted with the correct tyres.
EDIT: mindf*** moment. A4 above should read A3. Apologies.
Edited by A900ss on Monday 12th November 19:34
Nanook said:
InitialDave said:
A900ss said:
A4 AWD is part-time 4WD and the 4WD only kicks in during acceleration not deceleration.
What? Where are you getting that from? In the A4, the engine is mounted longitudinally, and the drivetrain is very similar to the A6, and assorted Subarus amongst other things.
Paddy_N_Murphy said:
You watched 18 minutes?
If you imagine it to be a really low budget episode from BBC Four's Slow Television experiment, such as All Aboard! The Sleigh Ride ...OK, OK, I'll admit it: I skipped about 17 minutes and caught that bit by blind luck
A900ss said:
it really makes no discernible difference hence people who live in the Alps and The Nordics mostly drive FWD cars fitted with the correct tyres.
No, in the Alpine regions I've been to they mostly drive the cheapest cars they can afford then put winters on them. It has nothing to do with engine braking. And most of them would kill for a Mercedes 4x4, though I don't know why. We asked a number of mates in Cham last year (ski school chaps etc), and first choice of car was nearly always a Merc SUV.DonkeyApple said:
s
tty little French FWD cars on winters are brilliant on snowy roads but the reason why most young locals drive them inthe Alps is because they don’t have jobs that pay enough to have a blinded up Merc SUV full of bottle rats.
I think I just said "...cheapest cars they can afford" in the previous post.tty little French FWD cars on winters are brilliant on snowy roads but the reason why most young locals drive them inthe Alps is because they don’t have jobs that pay enough to have a blinded up Merc SUV full of bottle rats. ...on snow?
Winter tyres of course.
If anybody claims differently, or just thinks they are somehow 'safe' with their 4wd on summers, let them watch this straightforward comparison:
Tyrereviews 2wd winter vs 4wd summer
On wet roads, they are roughly the same, on dry cold roads, the summers may be a bit better. And on acceleration 4wd is always better in the dry/wet, but only relevant if you need to win dragraces.... But once the white stuff comes falling down summers don't have a chance. At all.
PS: for those in the nordic countries: put descent nordic winter tyres on your 4wd cars instead of all seasons 21" tyres whatever. The difference is just as large as above especially on ice...
Regards,
Onehp from Sweden
PSS in summer, Icecontact 2 studded (190 studs/tyre) in winter.
Winter tyres of course.
If anybody claims differently, or just thinks they are somehow 'safe' with their 4wd on summers, let them watch this straightforward comparison:
Tyrereviews 2wd winter vs 4wd summer
On wet roads, they are roughly the same, on dry cold roads, the summers may be a bit better. And on acceleration 4wd is always better in the dry/wet, but only relevant if you need to win dragraces.... But once the white stuff comes falling down summers don't have a chance. At all.
PS: for those in the nordic countries: put descent nordic winter tyres on your 4wd cars instead of all seasons 21" tyres whatever. The difference is just as large as above especially on ice...
Regards,
Onehp from Sweden
PSS in summer, Icecontact 2 studded (190 studs/tyre) in winter.
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
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