Car is 2016 W213 E220d. In for yet more warranty work today and called late afternoon to say they can't test drive it as tyres are too dangerous. The central block of tread has 5mm at least right across the legally required section. *I think new tyres have some 8mm tread so they haven't worn much. *But the inside shoulders have worn away to quite literally nothing. You can't see this damage or wear from the roadside unless you stick your head under the car and look at tyres from centre line of vehicle. This means it's pretty much a hidden failure and one which an otherwise careful walk round inspection would miss. What I don't understand is that the car had its first service 4 months and 6000 miles ago and no problems were flagged. Though I was told today they wouldn't tell me if it was wearing right down on the shoulder until, like now, it got to the point of showing carcass. *This seems unreal to me. They are happy to let accelerated wear continue on a part of the tyre which your can't see but not tell the owner. With the risk of blow out well before next service/inspection. Seems like a dereliction of duty to me* I got some utter rubbish about driving whilst flat can cause it which was later changed to driving with low pressure. It's fitted with pressure sensors, has never been run low. They said oh they only trigger with sudden pressure changes; no I said, this system displays actual pressure *(not relying on abs/wheel rotation speed like the simple warning systems). They then said it's likely tracking is out and also said it's common (?!) on heavier vehicles. It must be massively out to destroy inner edges but leave 15000 to 30,000 miles of wear on the main bloody tyre. And if it's common, why do Merc spec that wheel/camber/toe angle then? So, question, based on the condition of the tyres in the pictures, what do you think has gone wrong and would/should they have seen this 6000 miles ago. Car is on 21500 miles now so it was seen with two thirds current mileage.