This seems wrong at first glance, it seems like the tire is rolling and should not need a lot to keep that happening. Until you consider that when the car is running at 60 MPH, the outside tread of the tire is going from zero when it is in contact with the road to 120 MPH at the top of the tire, to zero again when it reaches the bottom again. Hundreds of times per minute. That is a lot of mass to accelerate and slow that often.
Thats not quite how it works. The tire is not going 120 MPH and it's not stopping and starting from zero?
The 285/60/20 has a circumference of 105"
At 60 MPH this equates to the tire rotating at 602 RPM
To get the surface speed in minutes you multiply: 105" x 602 rpm = 63,210 inches per minute
Divide it by the inches in a mile 63,360
63,210 / 63,360 = 0.9976 this is the surface speed in miles per minute
Multiply by 60 to get the MPH and its of course 60 since it has to be at least the speed of the vehicle.
But its rotating a constant velocity so it never changes speed. This is why larger tires like on a semi spin slower because the larger the diameter the higher the surface speed for a given RPM.
I do endless calculations like this for my job all the time.