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Disk Brake Dialog Box

This Brake Designer dialog is used to edit the physical parameters of a hydraulic disc (caliper) brake. The dialog includes a schematic preview drawing of the brake, updated to reflect the current dimensions.

Caliper

Number of Pistons Drop-down list selecting the number of caliper pistons (1, 2 or 3).

Piston Diameter (in) Diameter of each caliper piston.

Push-out Pressure (psi) Pressure required to overcome the caliper seal/return force and begin developing brake torque.

Rotor

Outside Diameter (in) Outside diameter of the rotor.

Inside Diameter (in) Inside diameter of the rotor swept (friction) surface.

Rotor Thickness (in) Thickness of the rotor (used for calculating the thermal mass of the rotor).

Lining (Inner and Outer columns)

The following parameters are entered separately for the inner and outer pads.

Pad Thickness (in) Thickness of the pad lining material.

Incl. Angle (deg) Included angle of the pad (the arc of the rotor surface covered by the pad).

Mechanical Efficiency Fraction of the actuation force actually delivered to the pads after mechanical losses.

Buttons and Results

Friction ... Opens the Lining Friction Properties dialog, used to edit the pad friction coefficient as a function of lining temperature.

Material ... Opens the Brake Designer Material Properties dialog, used to edit the rotor and pad material thermal properties.

Apply Recomputes the results below from the current physical parameters.

Brake Factor (read-only) Calculated ratio of total rotor drag force to actuation force for the brake.

Actuation Factor (read-only) Calculated actuation force per unit of system pressure.

Brake Torque Ratio (in-lb/psi) (read-only) Calculated wheel brake torque per unit of system pressure. On pressing OK, this value replaces the Brake Torque Ratio in the Brake Assembly dialog.

Removed options

The following entries from the previous manual are no longer present in this dialog:

  • Number of Rotors — removed; the model uses a single rotor per wheel.
  • Middle Pad Thickness — removed; pad thickness is now entered per inner/outer pad.
  • Preview button — removed; the schematic preview drawing is now always displayed in the dialog.

Source topic: DiskBreakDlg.htm — updated from source code (HVEINV-64, Physics) 2026-07-05.

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