Where I live, summer tires are required by law to have 1.6 mm minimum tread depth, and winter tires 3 mm. However, a general recommendation is that summer tires should have 4 mm tread for optimal resistance against hydroplaning.
However, there are various sizes of tires and cars. Tires can be smaller or larger in radius, or narrower or wider in width. Similarly, vehicle weight varies a lot, and a small hatchback can weigh half of that of a big electric SUV.
My SUV for example had 8.3 mm initial tread depth on the stock summer tires, far more than my previous small hatchback had. But the tires are both larger in radius and width, and the vehicle weight is nearly 50% more than in the previous small hatchback.
Is there any information on whether tire size (radius or width), or vehicle weight affect the safe minimum tread depth needed to avoid dangerous hydroplaning?