ABS (Anti-Lock Braking System)

Deep dive

Bentley explains the HPDE context in Ultimate Speed Secrets: "Anti-lock braking systems (ABS) are perhaps the most important safety device to ever be developed for street vehicles. However, ABS has not found much use on purpose-built race cars because all the major series prohibit it, mainly as a cost-controlling measure." For HPDE drivers he adds: "When ABS is functioning properly, it actually allows you to steer the car, even under hard braking. Without ABS — or when wheels lock — you lose steering because a sliding tire creates very little lateral force." Limpert's Brake Design and Safety provides the engineering requirement: ABS must retain steering during control "for rapid pressure increases up to 1,500 bar/s." The HPDE Techniques guide notes that intermediate drivers learn to treat ABS as a tool, not a crutch: "Intermediate drivers often switch to a more performance-oriented ABS mode that tolerates slight tire slip (like a 'Sport ABS') before intervening. This lets them approach threshold without ABS prematurely cutting in." The key coaching point for HPDE: use ABS as an emergency backstop, but aim to trail off brake pressure before ABS activates — the tires are at their absolute peak grip just before ABS intervention, not during it.