One Of Them "No! No! No!" Moments...

[Bonefishblues]

Originally Posted by tt82

Tests have shown that a winter tyre is capable of stopping a car in a shorter distance on a flooded road in temperatures at 4 degrees C, than what a summer tyre can. Perhaps part of the compound being softer, allowing the tread blocks to move and generate more heat, also helps them disperse the water more effectively, thus raising the point at which the car aquaplanes.

I don't think it being suggested that a winter tyre wont aquaplane, just that they might be able to cope with higher levels of surface water before they do and that they offer more grip to help regain control of the vehicle afterwards, compared to a summer tyre.

The last word was yours. HTH.

[Simon Jones]

Originally Posted by green van man

I would not try it in the Volvo as the absence of the low ratio box would lead to having to use the brakes and likely runaway.

My XC70 has got hill descent control which holds the speed constant with the ABS. Not tried it anger but had a play with it on a slippy hill and it seems to do the trick. I believe it also works in reserve which is handy if you attempt to go up a hill that's a bit too steep

[apersson850]

You mean reverse, I presume? Yes, if you keep your foot away from the accelerator it will allow max 7 km/h backwards and 10 km/h when going the normal way.
It will apply the brakes with the ABS system active. Thus in reality it will brake each wheel as much as it can take, if the speed is increasing.

[green van man]

Originally Posted by apersson850

You mean reverse, I presume? Yes, if you keep your foot away from the accelerator it will allow max 7 km/h backwards and 10 km/h when going the normal way.
It will apply the brakes with the ABS system active. Thus in reality it will brake each wheel as much as it can take, if the speed is increasing.

With the speed increasing it tries to brake the wheel, wheel locks, brake releases and repeat, meanwhile speed is increasing.
With low ratio gearbox wheels are always turning even if sliping over the surface and speed in 1st gear is slow walk so always able to steer, even if into the bank to stop you.

My old technology disco 1 will come down a steep wet grass slope with no drama while more modern stuff is locking releasing locking wheels with the abs based hill descent, some of the skid marks are 4 foot long, especially where the driver bottles it and has their foot on the pedal.

I do not say hill decent cannot be a valuable aid but aid it is and I would rather my low ratio box and gears to keep speed to slow walk than an on off braking system. It's the interaction between the tyre contact patch and surface that gives control, the fewer variables the better in my view.

Paul.

[Tannaton]

Originally Posted by green van man

With the speed increasing it tries to brake the wheel, wheel locks, brake releases and repeat, meanwhile speed is increasing.
With low ratio gearbox wheels are always turning even if sliping over the surface and speed in 1st gear is slow walk so always able to steer, even if into the bank to stop you.

My old technology disco 1 will come down a steep wet grass slope with no drama while more modern stuff is locking releasing locking wheels with the abs based hill descent, some of the skid marks are 4 foot long, especially where the driver bottles it and has their foot on the pedal.

I do not say hill decent cannot be a valuable aid but aid it is and I would rather my low ratio box and gears to keep speed to slow walk than an on off braking system. It's the interaction between the tyre contact patch and surface that gives control, the fewer variables the better in my view.

Paul.

There are other factors involved, such as tyres, the weight of the car, profile of tyres and the viscosity of the slippery surface you are on. On wet muddy banks the Disco will do well because you get most braking effort on wet mud when there is a slight slip/drag - i.e. the wheels are turning slightly slower than the vehicle speed but not fully locked up. This is where some of the traction control/electronic cars might not perform as well. This is why when stuck in mud it's actually better to turn the traction control off and spin the wheels to get going.

However the Disco would not be so good in going up the hill, where it's at risk of cross-axling (i.e. spinning a wheel on each axle) this is where traction control comes into its own.

But yes I agree with you 100% it's all about how the tyres meet the surface and controlling that and driving the vehicle to the conditions.

[Tannaton]

Back to the OP...

I believe I am a good careful driver with a safe car but you can never predict what will happen next no matter how careful you are... such as:

https://www.youtube.com/watch?v=SRlbMv0M65Y

I have had slow punctures and tyres bubbling/de-laminating that have caused "interesting" moments over the years so it's not as simple as going too fast.

I agree 110% with others comments that we have taken a huge backwards step in removing the hard shoulders from some of our motorways. I fear that it is only a matter of time before a whole family is horrifically and needlessly wiped out in an instant and this could easily happen without it being anyone's fault. It will be another tragic realisation, like with the fire in London last year, when we realise what we thought was a safe combination is in fact lethal.

BTW I would stop and help too, as I hope others would if it was me or my wife dazed or unconscious in the stranded car.

[Simon Jones]

Originally Posted by apersson850

You mean reverse, I presume? Yes, if you keep your foot away from the accelerator it will allow max 7 km/h backwards and 10 km/h when going the normal way.
It will apply the brakes with the ABS system active. Thus in reality it will brake each wheel as much as it can take, if the speed is increasing.

Yes, sorry, autocorrect failure

[Bonefishblues]

Originally Posted by Tannaton

Back to the OP...

BTW I would stop and help too, as I hope others would if it was me or my wife dazed or unconscious in the stranded car.

I think the debate is about where and how to stop and what form the help offered takes. It's a sad but notable fact that the only person killed on the M5 the other week in a multi-car pile up was a young lady who had left her vehicle.