I normaly get around 390-410 from a tank with Pirelli P Zero Neros with around 30 left on the trip. Just finished my first tank with Michelin alpin's. 450 with 30 miles left on the trip. That's some difference.

Michelin are always a better tyre than Pirelli but that and the fact one is a winter tyre aside it's still a big jump is that.

Maybe it's a combination of things like the colder weather and sub consciously your trying to drive easy on the winter tyres as on a dry road they will wear relatively fast.

I dunno but at least the MPG has not gone down

Today was are first day of cold weather (-1). The rest of the tank was above 10c.

I've also noticed its happy to rev lower than the pirelli's as they would struggle below 1800rpm. That aside I tend to drive at or above 2k so I've always got power available.