akirk wrote:What did people do before winter tyres were invented?
Going back 20-30 years, as jont- says, wheels and tyres in the UK were smaller diameter and narrower. For example, my 1986 Alfa GTV6 had 195/60R15 tyres on 6J wheels, considered low profile at that time, whereas these days an entry-level Audi A1 has 205/55R15 tyres while higher trim levels have larger lower profile, up to 225/35R18. This is for, at the top end, similar performance in a slightly lighter car. Utterly ridiculous.
Over the years there has been a lot of development by tyre manufacturers, in response to public demand and pressure from car manufacturers, to produce tyres that are much more economical - the car manufacturers are pulled in two diametrically opposite direction: the fashion for larger, wider wheels with ever lower profile tyres, and the regulations under which they operate in order to sell less and less polluting vehicles. The unintended consequences are 'normal' tyres that work very well in warmer conditions, but which are less effective as temperatures drop below a couple of degrees centigrade, and especially so when the road surfaces are slippery. And you won't find manfacturers fitting tyres that are more suitable for the range of UK weather conditions as standard if they aren't as economical as 'normal' tyres.
akirk wrote:that doesn't mean that a car on normal tyres can't be driven
Depends on the specific car, the conditions, and the specific tyres.
akirk wrote:If the temperature drops you can change tyres - but the implication and advertising is based around being able to continue driving in the same way - i.e. the winter tyres 'fix' the temperature dropping - no mention of the need to change how you drive.
Just as 'normal' tyres have been vastly improved, so have tyres targeted at cold, slippery conditions, as well as those which are designed to work reasonably well over a wider range of conditions. With appropriate tyres, there is much less need to change the way you drive, which isn't to say drivers shouldn't still drive to the conditions. That's actually the point; when people talk about driving to the conditions, they tend to forget how much difference the tyres make to that equation; in wintery weather, good appropriate tyres shift 'the conditions' significantly when compared to less appropriate 'normal' tyres.
akirk wrote:My Z3 has to be driven very differently on wet roads / before the tyres are warmed up / on cold days - but it is still driveable, I just change how I drive it...
Perhaps you could find different tyres that aren't optimised for warm dry weather? They'd almost certainly change your perception of your car.
akirk wrote:The decision has to be around how much extra benefit you would gain from changing rubber compound v. cost to do so... I have friends in Northumberland where it makes sense - for me in the Cotswolds (and not in the hilly part) it makes little sense
One of my friends in a hilly part of the Cotswolds - a long-term advanced driver - used to find that sometimes he couldn't get home so, for him, winter tyres made his life a heck of a lot better.
there is only the road, nothing but the road ...