The classic Brakes from the Lear 60 came from the Learjet 55. They are identical. There is a SB that upgrades the "classic" 2-rotating disc Brakes to 3-rotating discs. This SB also adds new Actuators to the MLG. The 60XR has the 3-rotating disc Brakes installed from the factory. I cannot make a statement on the operation, since I am no pilot.