Advantages of 4WD on ordinary saloons?

[RobM77]

TooMany2cvs said:

RobM77 said:

It's also worth pointing out that many people citing traction as a requirement for 4WD are coming from FWD, where the front wheels get lifted off the ground giving you less traction when you accelerate, and the more you accelerate, the less traction you get. In most RWD cars of normal power, the opposite happens, so it's possible to get full throttle in 1st gear without wheelspin, even in the wet.

If you're giving it THAT much clog in poor weather/road conditions, then traction is not your biggest problem.

..and if you're concerned about the impact of a bit of wheelspin on road safety, then traction is not your biggest problem!! The best things you can do to stay safe on the road are good observation, planning ahead, leaving yourself room, and driving at an appropriate speed. A bit of slip <10mph pulling away from rest is a long way down the priority list if you're a reasonably capable driver (i.e. not one of these idiots from You Tube who fishtails into a lamp post).

Edited by RobM77 on Tuesday 16th October 12:06

[mariav3]

good one ..

[Kuji]

TooMany2cvs said:

ericmcn said:

InitialDave said:

Have you driven a car with winter tyres in icy/snowy conditions?

Nope

And that's the entirety of what we need to know to put Eric's opinions into context.

But this thread is about AWD cars.

Not winter tyres, for which there is an existing thread where you can twiddle your fudge all day long.

[nickfrog]

ericmcn said:

yes, but as per earlier in the thread AWD is useful not just for snow but overall traction, stability and handling.

As clearly demonstrated by several people including an automotive engineer using your own example of the fallen tree, it's quite litteraly the opposite. 4wd will blunt the handling.

[TooMany2cvs]

Kuji said:

TooMany2cvs said:

ericmcn said:

InitialDave said:

Have you driven a car with winter tyres in icy/snowy conditions?

Nope

And that's the entirety of what we need to know to put Eric's opinions into context.

But this thread is about AWD cars.

Not winter tyres, for which there is an existing thread where you can twiddle your fudge all day long.

Not much of an "advantage" if it can be bettered by changing a cheap consumable, without all the weight, mechanical drag and complication penalties.

[Kuji]

J4CKO said:

I am really not sure what you lot are actually arguing about any more ?



4WD gives more traction which is useful but not essential some of the time, it is a lot more useful when it snows.

The correct tyres for the situation make as much, sometimes more difference.

RWD may be more fun for some drivers who are interested, but largely depends on a given car as a package.

Its typically a bit heavier.

Some people are arguing about how much better their own choice of vehicle is over an AWD car.

They may have to insist that they are the only ones allowed to have winter tyres to achieve their goal, but it keeps them happy and off the street corners.

[Kuji]

TooMany2cvs said:

Kuji said:

TooMany2cvs said:

ericmcn said:

InitialDave said:

Have you driven a car with winter tyres in icy/snowy conditions?

Nope

And that's the entirety of what we need to know to put Eric's opinions into context.

But this thread is about AWD cars.

Not winter tyres, for which there is an existing thread where you can twiddle your fudge all day long.

IMHO: Not much of an "advantage" if it can be bettered by changing a cheap consumable, without all the weight, mechanical drag and complication penalties.

It certainly took you ages and a heap load of out of scope statements for such a simple one line opinion.

[InitialDave]

Kuji said:

Some people are arguing about how much better their own choice of vehicle is over an AWD car.

They may have to insist that they are the only ones allowed to have winter tyres to achieve their goal, but it keeps them happy and off the street corners.

Don't try and paint it as confirmation bias in favour of what people already own. Eric is the only one demonstrating that.

And plenty of people are pointing out AWD with winter tyres is an excellent combination.

[nickfrog]

Kuji said:

But this thread is about AWD cars.

Not winter tyres, for which there is an existing thread where you can twiddle your fudge all day long.

The 2 are intrinsically linked. Separating them would be absurd.

[Mr Whippy]

I’ve an R32 Golf that I wish had better awd, or was just rwd.

And a BMW 335xd that is awd but I can’t really tell, but may as well just be rwd (and manual) 90% of the time.

The only awd I truly liked and thought was worth it was a 2.9 XR4x4 because you could play around with it at lower speeds and enjoy over the limit handling stability.

[jagnet]

Kuji said:

But this thread is about AWD cars.

Not winter tyres, for which there is an existing thread where you can twiddle your fudge all day long.

Given people's propensity to buy AWD vehicles for their perceived benefits in the winter, the two are linked too closely to discuss AWD without also discussing tyre choice. You only have to look at eric's contributions to realise that for many people, having an AWD vehicle is the be all and end all to winter driving and won't even entertain the idea that they're approaching the problem of dealing with reduced grip from the wrong direction.

In slippery conditions with tyres being equal the AWD clearly has a traction advantage and in some circumstances an advantage in deceleration when engine braking. In cornering there can be a slight improvement in stability although total lateral grip remains the same as a 2WD drive car.

Given that in snow a 2WD car on winter tyres can out accelerate, out brake and out corner a 4WD vehicle on summers it begs the question why do so few UK driven AWD vehicles use winter tyres if their owners are so keen on their car's improved winter abilities? Anecdotally I'm seeing more SUVs in the UK wearing all season tyres than I did a few years ago, but summer tyres still appear to be the norm.

If a 2WD vehicle can still maintain relatively normal speeds in the snow as per the earlier Saab video, where does that leave a 4WD's extra abilities if it too had winter tyres? I'm not denying that there'll be circumstances where the snow gets too deep for a 2WD and the 4WD can keep going, but if both vehicles have normal ground clearance then it'll be a very narrow window of opportunity. Would an AWD vehicle on winters have arrived home any earlier than the Saab in the video or with a greater margin of safety? Imho not really.

Meanwhile the AWD vehicle invariably costs more to purchase, there's potentially greater maintenance bills, there's extra weight to carry around from the drivetrain and greater frictional losses which all cost more in fuel bills.

I get that some may simply prefer the way an AWD vehicle feels, but that's a subjective assessment rather than it objectively being "better".

Everyone's different, but given it's downsides I'd need a bit more convincing of the advantages of AWD than avoiding wheel slip at 5mph on a damp junction to warrant changing vehicles anytime soon.

[80quattro]

After reading some earlier posts, I pondered purchasing a set of winter tyres for my BMW 530i, as 265/35x18's summer tyres were not the best for removing said BMW from my driveway last winter.

After looking into prices, I opted for an entire car instead, for slightly lower outlay.

[blade7]

RobM77 said:

It's also worth pointing out that many people citing traction as a requirement for 4WD are coming from FWD, where the front wheels get lifted off the ground

I'll have a pint of what you've been drinking.

[tuga2112]

Norfolkandchance said:

Hi,

I am often surprised to see ordinary saloons with four wheel drive and I wonder what the buyer is looking to gain. I'm talking about 320d X drives, for example, but i see it on lots of (mostly German) saloons.

I can see an advantage if you live in somewhere hilly and cold, like the Yorkshire Dales or somewhere, but I don't. I live in Norfolk.

Modern cars have very good traction and stability systems, so 4WD isn't needed to prevent accidental spins exciting damp roundabouts.

The cars aren't particularity powerful. Its not like an M5 where the 4WD may well make it faster because they are traction limited.

They don't have raised ride height and are fitted with ordinary summer tyres so they wouldn't be much better at negotiating a rutted farm track or pulling a horse box out of a field.

So is there something I'm missing. Or have they just fallen for 30 years of marketing? Or is it they want reassurance for the few days per year when there is snow on the ground.

simple.. its a matter of feeling like your getting that extra quality out of your car.
its also better for those 3 days in the year when theres ice on the roads.... (assuming your not going to take advantage of the excuse to stay home)

i have a awd and a fwd that i drive both regularly both are not saloons (one is a sports convertible and other is WRC homolgation model) theres clearly a difference in the driving experience, but i dont think a saloon driver would push their car to those extremes

[RobM77]

blade7 said:

RobM77 said:

It's also worth pointing out that many people citing traction as a requirement for 4WD are coming from FWD, where the front wheels get lifted off the ground

I'll have a pint of what you've been drinking.

Sorry, that was my attempt at simplifying the physics. As I'm sure you know, when any vehicle accelerates, the force down through the rear tyres increases, and the force on the fronts decreases (known as 'weight' transfer). The more you accelerate, the more this happens. FWD cars therefore get less traction the more they accelerate, and RWD cars get more.

[996TT02]

To state the obvious that should have eliminated 14 of the 15 pages so far in this thread - AWD is great ("better") if you need it, pointless ("worse") if you don't.

Whether you do or don't is a whole different argument altogether, but again simply, if you have traction problems on a 2WD with appropriate tyres for the conditions, then it's a yes, otherwise it's a no. Simple enough?

[blade7]

RobM77 said:

blade7 said:

RobM77 said:

It's also worth pointing out that many people citing traction as a requirement for 4WD are coming from FWD, where the front wheels get lifted off the ground

I'll have a pint of what you've been drinking.

Sorry, that was my attempt at simplifying the physics. As I'm sure you know, when any vehicle accelerates, the force down through the rear tyres increases, and the force on the fronts decreases (known as 'weight' transfer). The more you accelerate, the more this happens. FWD cars therefore get less traction the more they accelerate, and RWD cars get more.

Yes I do know that, but as this thread is going around in circles I attempted to inject some humour .

[anonymous-user]

This thread has become almost a parody, like "Ask A Total Prick From An Internet Forum" but about Subarus rather than a Civic Type-S. Embarrassing to read.

[MikeDB1]

Watch Series 2, Episode 2 of James May's Cars of the People and it puts it very eloquently in the first few minutes why all cars should have 4WD.

https://www.bbc.co.uk/iplayer/episode/b06zn8z9/jam...

I love the bit about horses being 4WD.

But seriously, without my Impreza I'd never have got anywhere last winter.

[300bhp/ton]

RobM77 said:

It In most RWD cars of normal power, the opposite happens, so it's possible to get full throttle in 1st gear without wheelspin, even in the wet.

My daily driver is circa 1400kg, 161bhp and 380Nm of torque, and you can get full throttle in 1st if you want to, even on a wet road.

I suspect TCS is likely still kicking in, even if you aren't aware of it. And most car makers restrict torque (and thus HP) in low gears anyway. So you can't actually get full power, even if it is full throttle.

A 161hp 1400kg car should easily be able to break traction.