Winter Tyres Question

[ukgroucho]

I'm dubious that you would have seen a gain that great A6S. You might see a bit but it's more likely you are "driving to the conditions" a bit more.

[A6S]

Same commute and gauge on car is hitting 49ish most days. Normally hover around 41mpg on the summers. If anything traffic has got worse with the cold so should expect less. 2 years I’ve had these winters and both year have seen significant improvement over the summers.
The 18s with 225 tyres are a damn sight lighter than the 19s with 255. Easily shaved 10kg a corner.
Noticed this with a courtesy car when I had my ultra . Se spec with 17s, same engine. The se managed almost 60mpg while mine was just under 50. Mine had the 19s. Same road, same commute.
All to do with unsprung weight and drag of the wider tyres.
Is that not why the black editions are in a higher tax band?

[NewAudi]

Driving the same route, times etc like any other times will see an improvment on winters. In my BiTdi about 3-4mpg and in the S6 about 1-2mpg. Hardly noticable.

As a total avg the difference between the BiTdi and the S6 is not that much actually - 10-12mpg when S6 driven nicely.