Everytime i have taken a car to the dealer for something or a service it says how much tread is on the tyres on the paperwork. it’s under the basic saftey checks they do when they have the car.
Yes it’s to make them more money, as well as it’s being a legal requirement. So theu don’t get sued for your illegal tyre blowing at 70 mph on the motorway mins after it’s been in their care.
As for the Mot that is a different check totally and last time mein went in for mot it needed the rear pads doing and Mb authorised it right there and then a tyre they won’t as it is our job to make sure they are road worthy and meet the legal requirement and it is us that will get points or a fine or even banned.
https://www.gov.uk/check-vehicle-safe
You’re responsible for making sure your vehicle is always safe to drive (‘roadworthy’). It can be unsafe even if you have a current MOT certificate.
You can be fined up to £2,500, be banned from driving and get 3 penalty points for driving a vehicle in a dangerous condition.
There are different rules for commercial vehicles.
Checks you should carry out
Every time you drive you should check:
the windscreen, windows and mirrors are clean
all lights work
the brakes work
Your vehicle’s handbook will tell you how often to check the:
engine oil
water level in the radiator or expansion tank
brake fluid level
battery
windscreen and rear window washer bottles – top up with windscreen washer fluid if necessary
tyres – they must have the correct tread depth and be free of cuts and defects
The handbook will also tell you when your vehicle needs to be serviced.
Tyre tread
Tread must be a certain depth depending on the type of vehicle:
cars, light vans and light trailers – 1.6 millimetres (mm)
motorcycles, large vehicles and passenger-carrying vehicles – 1mm
Mopeds only need to have visible tread.
There must be tread across the middle three-quarters and around the entire tyre.