In message , at 12:43:44 on
Thu, 30 Oct 2014, Recliner remarked:
across a patch of dry road. Those are the sort of conditions where
modern hatchbacks with front wheel drive just sit there literally
spinning their wheels.

Rear wheel drive without snow tyres or diff lock is even worse. At least with
FWD you have some semblance of control in snow and ice but with RWD you have
to be colin mccrae even at low speeds as the tail just wags in the direction
of the road camber. And it gets stuck just as easily.

The other problem is that in most front-engined, RWD cars, more of the
weight is over the front wheels, so the only driven wheels are lightly
loaded.

The best car I ever had for traction and steering in the dry was RWD
mid-engined. The only consideration was how far you could see ahead as
safe, because it could corner a roundabout at 60mph with a couple of
flicks of the wrist, and without the slightest suggestion of a slide.

But it didn't do well in snow, because the tyres were too wide. They
were also too wide to be able to spin in the dry from the available
power (Lotus Twin-Cam, but only 1600cc; the other car I've been talking
about had a later Lotus 2.2 litre twin-cam engine).
--
Roland Perry

In message , at 15:40:13 on Thu, 30
Oct 2014, Neil Williams remarked:
Doing it on a dry road is good practice for when it's wet/icy.

True, but it should not be a dry road with other traffic about, as that
increases the risk of an accident for no good reason. Find an empty
car park, or book a track day, or do it on a quiet back street with
nobody around.

Obviously one isn't going to drive over-enthusiastically when there's a
lot of other traffic around, but neither is it necessary to restrict it
to off-road. That's one of the things an Advanced Driving course
teaches.
--
Roland Perry

In message , at 12:40:37 on Thu, 30
Oct 2014, Neil Williams remarked:
The times I found locked diffs the most useful was driving on
snow/ice in the heart of winter where you could pretty much expect
never to come across a patch of dry road. Those are the sort of
conditions where modern hatchbacks with front wheel drive just sit
there literally spinning their wheels.

Most probably, but unless you live in the middle of nowhere (or go to
the middle of nowhere) that's not all that common a use-case.

I used to live in a village just outside Henley, which isn't exactly
"nowhere", and it was quite useful to be able to drive through a foot of
snow as it if wasn't there.

The worst time I was held up by numerous other drivers whose cars were
incapable of moving due slip (near Henley they were simply abandoned and
possible to overtake) was on the A10 just north of Royston. Again not
exactly the sticks. iirc I managed to make progress by driving along the
grass verge because the road was so cluttered with impotent hot-hatches.

FWIW, front wheel drive has a big advantage over rear in snow and ice.
One of those situations where cheaper is also better at that time of
year.

FWD is better to begin with in light snow/ice, but once conditions have
deteriorated sufficiently I'm sure that RWD is better. (Assuming one
doesn't have 4WD).
--
Roland Perry

Roland Perry wrote:
In message , at 12:40:37 on Thu, 30 Oct
2014, Neil Williams remarked:
The times I found locked diffs the most useful was driving on
snow/ice in the heart of winter where you could pretty much expect
never to come across a patch of dry road. Those are the sort of
conditions where modern hatchbacks with front wheel drive just sit there
literally spinning their wheels.

Most probably, but unless you live in the middle of nowhere (or go to
the middle of nowhere) that's not all that common a use-case.

I used to live in a village just outside Henley, which isn't exactly
"nowhere", and it was quite useful to be able to drive through a foot of
snow as it if wasn't there.

The worst time I was held up by numerous other drivers whose cars were
incapable of moving due slip (near Henley they were simply abandoned and
possible to overtake) was on the A10 just north of Royston. Again not
exactly the sticks. iirc I managed to make progress by driving along the
grass verge because the road was so cluttered with impotent hot-hatches.

FWIW, front wheel drive has a big advantage over rear in snow and ice.
One of those situations where cheaper is also better at that time of year.

FWD is better to begin with in light snow/ice, but once conditions have
deteriorated sufficiently I'm sure that RWD is better. (Assuming one doesn't have 4WD).

Even though RWD cars usually have less weight on the driving wheels? I
know my RWD car is pretty bad in snow, as the cast iron block Diesel engine
is heavy and the aluminium body light. The unnecessarily wide tyres don't
help.

Roland Perry wrote:
In message , at 12:43:44 on
Thu, 30 Oct 2014, Recliner remarked:
across a patch of dry road. Those are the sort of conditions where
modern hatchbacks with front wheel drive just sit there literally
spinning their wheels.

Rear wheel drive without snow tyres or diff lock is even worse. At least with
FWD you have some semblance of control in snow and ice but with RWD you have
to be colin mccrae even at low speeds as the tail just wags in the direction
of the road camber. And it gets stuck just as easily.

The other problem is that in most front-engined, RWD cars, more of the
weight is over the front wheels, so the only driven wheels are lightly
loaded.

The best car I ever had for traction and steering in the dry was RWD
mid-engined. The only consideration was how far you could see ahead as
safe, because it could corner a roundabout at 60mph with a couple of
flicks of the wrist, and without the slightest suggestion of a slide.

But it didn't do well in snow, because the tyres were too wide. They were
also too wide to be able to spin in the dry from the available power
(Lotus Twin-Cam, but only 1600cc; the other car I've been talking about
had a later Lotus 2.2 litre twin-cam engine).

Yes, mid-engine RWD is the optimal layout for traction and handling, which
is why so many high performance sports cars use it, even though it's lousy
for space utilisation. For pure traction, of course, the Porsche 911
rear-engine layout is best, but it can have treacherous handling.

On 2014-10-30 15:39:55 +0000, Roland Perry said:

Having had a Range Rover for three or four years, I can't think of any
way in which it's possible to abuse the 4WD.

Does it have a diff-lock? If so, engaging the diff-lock when on grippy
ground would be one way - you could knacker the propshafts.

You need 4WD when driving on a couple of inches of snow. When I had my
Rage Rover it was one of the few vehicles which could make it out of
the village (the others were also 4WD, tractors etc).

Ah, you live in the middle of nowhere where roads are not gritted.
Makes sense in that context.

A slipping wheel doesn't have zero traction. Especially in the dry.

AIUI a spinning wheel has less traction than a wheel on the edge of
slipping. That certainly feels the case when attempting to pull off a
bit quickly - you start off quicker if you back off the power to stop
the spin than if you keep your foot to the floor and keep the spin,
despite what any US movie would say. (My Vectra is terrible for
spinning the front wheels, the 1.8 VVT engine is quite torquey but not
very heavy, and the wheels are quite far forward so there is little
weight directly over them, as well as the front wheels being quite far
forward which means that a heavy load in the boot serves to lighten the
load on the front wheels yet further).

Neil
--
Neil Williams
Put my first name before the @ to reply.

On 2014-10-30 15:59:12 +0000, Roland Perry said:

FWD is better to begin with in light snow/ice, but once conditions have
deteriorated sufficiently I'm sure that RWD is better.

I doubt it. The problem with RWD is that once things start to slip you
lose steering, and the back end just fishtails. Whereas any grip a FWD
car can get pulls it in the desired direction.

4WD of course does both, but it isn't viable to fit that to all cars,
nor is it necessary. I have no need for a 4 wheel drive car - on the
week or so in a year if that when things get treacherous, I'll work
from home and leave the car on the drive, and do other local travel on
foot or in other peoples' vehicles, i.e. buses and taxis where still
running. And of course use the train to do long-distance travel, as
despite what people say about it in very bad conditions it usually gets
through when being on the roads is seriously ill-advised.

Neil
--
Neil Williams
Put my first name before the @ to reply.

In message , at 17:59:57 on Thu, 30
Oct 2014, Neil Williams remarked:
On 2014-10-30 15:39:55 +0000, Roland Perry said:

Having had a Range Rover for three or four years, I can't think of
any way in which it's possible to abuse the 4WD.

Does it have a diff-lock? If so, engaging the diff-lock when on grippy
ground would be one way - you could knacker the propshafts.

Range Rovers from 1989 onwards didn't have diff-locks, but provided
permanent 4WD using a fully automatic viscous coupling device.

You need 4WD when driving on a couple of inches of snow. When I had
my Rage Rover it was one of the few vehicles which could make it out
of the village (the others were also 4WD, tractors etc).

Ah, you live in the middle of nowhere where roads are not gritted.
Makes sense in that context.

I did when I had the Range Rover. Not only were the roads not gritted
because they were relatively minor, they would have been impassable by a
regular gritting lorry.

--
Roland Perry

In message
-septemb
er.org, at 16:14:19 on Thu, 30 Oct 2014, Recliner
remarked:
FWD is better to begin with in light snow/ice, but once conditions have
deteriorated sufficiently I'm sure that RWD is better. (Assuming one doesn't have 4WD).

Even though RWD cars usually have less weight on the driving wheels? I
know my RWD car is pretty bad in snow, as the cast iron block Diesel engine
is heavy and the aluminium body light.

The problem with FWD in very slippery conditions is that the front
wheels tend to slide sideways on the camber and very quickly end up
stuck against the kerb. It's then very difficult to recover the
situation and get back towards the centre of the road. In a RWD car you
have a much greater chance of keeping the front away from the kerb, even
if the rear is bumping along the kerb - indeed in that configuration
it's naturally pointing towards the centre of the road.

It's not about the weight distribution, because in such conditions *any*
traction is useful, getting "more" because of the weight distribution is
merely a bonus.

The unnecessarily wide tyres don't help.

That's the downfall of many a hot-hatch in the snow.
--
Roland Perry

In message , at 18:04:13 on Thu, 30
Oct 2014, Neil Williams remarked:
On 2014-10-30 15:59:12 +0000, Roland Perry said:

FWD is better to begin with in light snow/ice, but once conditions
have deteriorated sufficiently I'm sure that RWD is better.

I doubt it. The problem with RWD is that once things start to slip you
lose steering, and the back end just fishtails. Whereas any grip a FWD
car can get pulls it in the desired direction.

A FWD car in poor conditions tends to have chronic understeer, and
applying more steering doesn't help. In a RWD car even if the front
wheels start to understeer you can "oversteer" the back by applying the
throttle, which corrects the line. A bit of fishtailing is easily coped
with.

4WD of course does both, but it isn't viable to fit that to all cars,
nor is it necessary. I have no need for a 4 wheel drive car - on the
week or so in a year if that when things get treacherous, I'll work
from home and leave the car on the drive, and do other local travel on
foot or in other peoples' vehicles, i.e. buses and taxis where still
running. And of course use the train to do long-distance travel, as
despite what people say about it in very bad conditions it usually gets
through when being on the roads is seriously ill-advised.

That strategy can work when a public transport option exists, but large
numbers of people don't have that option. As for driving being
"ill-advised", then I'd agree that many modern 2WD vehicles are hopeless
in the ice/snow (I wonder how well ASC will fix that), but 4WD makes a
staggering improvement.
--
Roland Perry