I got stuck again today... on my own drive. It's about a... 1 in 4 million angle.. ie none. and I couldn't get up it.
I got out and studied the tyre tracks.
235/40's were never meant for snow, clearly, but it's the fact that they have no real cross groves that stood out.
I did get out today... did 200 miles to Essex and back to Bucks.. M25 was clear and nice, but A41 back to bucks was hell. Part slush, part ice, part snow, part tarmac...
It was while I was in Essex that I took a good look around lots of different tyres on different cars.
Here's what I, unsuprisingly, found.
The narrow stuff tyres you find on little hatchbacks have lots of blocks of rbber and have no definde grooves around their circumferance.
Look at this 165 pirelli (it'd just an example of the general pattern)
Now, that has as many grooves going ACROSS the tread as going around it.
Now check out a large 235 continental
With the exception of the edges, it has minimal left to right grooves. In fact it's prolly the reason why letting my tyres down from 36 to 24 made a difference to pulling away.. it allowed the centre to flex inward and the outter tread did a job. My own ones, are worse than this picture.
This is prolly not a revelation in anyone's eyes but it IS worth thinking about before you make a banana of yourself trying to get somewhere that a little Ka has done in one go, in your large saloon.
If anyone has any photo's of their own tyres and what they're like in this snow it would help.
All I know is that I cant accelerate or break at all but I can steer a tiny bit.