There are dozens of tyre manufacturers and when Autobild or whoever does for instance a "Summer" tyre test, so all the tyres are suitable for the same ambient temperature, the stopping distance and handling can vary hugely between the various tyres. So my point was if tyre safety was really a main concern for Mercedes or indeed any car manufacturer why don't they just fit tyres that come out best in the tests as standard or even tell owners not to fit certain makes of tyres(that a bit big brotherish!). I presume they'll just say that each tyre still performs within the safety parameters which is why I was a bit taken aback by their opinion of the all season tyre.
Mercedes-Benz (not necessarily a franchised dealer) will only recommend tyres which have been officially homologated as Original Equipmemt for Mercedes-Benz. That is to say that they have been designed specifically for Mercedes applications, extensively tested as such, optimised and finally approved by Mercedes-Benz. As a result Mercedes can recommend homologated tyres.
Based upon their response I suspect that means that V-rated winter tyres have been homologated, but W-rated winter tyres haven’t. It also suggests that all season tyres of any speed rating haven’t been homologated either. As a result Mercedes-Benz can only recommend V rated winter tyres for use in winter driving conditions, because those are the only ones they’ve approved.
To expect Mercedes to recommend a tyre which they have not specified or approved would be like expecting them to say “we recommend X-brand brake pads because I watched a You Tube video and read a magazine article which reviewed them”. Those information sources are really useful for consumers who don’t have their own testing/data, but not so great for manufacturers who do.
The YouTube and magazine tests/reviews are very informative for consumer but ultimately are very limited for manufacturers. They’re point in time tests, with very limited test scenarios and very limited duration. That’s much more information than consumers would otherwise have but car and tyre manufacturer testing scenarios are much much more extensive and even test tyres to destruction.
To approve the tyre - and therefore buy millions of them to fit to new cars or recommend their use as replacement tyres to millions of customers - and all of the practical, safety, commercial, legal and other implications that comes with it, then Mercedes need to know how the tyre performs in more than just a point in time test performed by a YouTube channel or magazine article.
You mentioned that it makes things difficult. It couldn’t be easier really. They have recommended a single tyre for use in wintery conditions, you can choose to follow their recommendation or choose something else. Either is fine, just make the decision which is right for you, and which offers you the least degree of compromise, it’s different for all of us.
PS I have two vehicles with all season tyres on them. They work well, but don’t work as well as summer tyres in summer or winter tyres in winter. They’re not on high performance cars and don’t cover many miles so the compromise on performance is outweighed by convenience of not changing tyres. The high performance cars which I use regularly in winter have winter tyres.
