Crimson Racing Wiki

Brake Master Cylinders

Subteam: SuspensionSubsystem: BrakesAssembly: Brake Calipers, Pads and Master CylinderCars: CR21, CR22, CR25, CR26I

Purpose

Convert pedal force into hydraulic pressure in the front and rear circuits.

Function

Two Tilton 78-series cylinders on a balance bar. Bore diameter sets the pressure generated for a given pedal force, and the ratio between the two bores sets the base brake bias before the balance bar trims it.

Design Process

Front and rear bore combinations were swept before selection: 5/8 front with 3/4 rear, 5/8 with 7/8, 7/10 with 13/16, 3/4 with 7/10, and 5/8 with 15/16. 5/8 in front and 13/16 in rear was chosen.

Analysis

At the selected sizes: wheel lock at 1.84 g, front pressure 8.4 MPa (1220 psi), rear pressure 5 MPa (720 psi), pedal force required 137 lbf, pedal sensitivity 340 N/g (77 lbf/g). Highest deceleration ever recorded on the car is 1.62 g (Corbin Glancy, NASCAR, 7 October 2023); repeated braking events sit at 1.48 g.

Full Material List

Tilton 78-series, purchased.

Reoccuring issues

Fault Vault, CR26I: the master cylinder and bias bar combination had one degree of freedom too many, causing brake migration. The master cylinders were zip tied in place for competition.

Properties

Front 5/8 in bore, rear 13/16 in bore. Quantity per car, as costed: 1

Still to document

Nothing in CrimsonStorage covers these yet.