1998
Brake steer
McLaren · MP4/13, MP4/12
Steward decisionVerified — secondary source
- Legal when raced
- Yes
- Closed
- 1998
- Survived
- same season
- Article
- —
What was exploited
A second brake pedal applying one rear brake independently, letting the driver tighten the car's line into a corner by braking the inside rear wheel.
The gap in the rulebook
No rule addressed independent rear-brake actuation as a steering input.
What it was worth
Improved turn-in and reduced understeer. First run on the MP4/12 in 1997.
How it was closed — Steward decision
Ferrari protested at the Brazilian GP and the three race stewards declared the system an illegal four-wheel-steering device — reversing four prior approvals by FIA technical delegate Charlie Whiting, which Ron Dennis publicly objected to. McLaren did not appeal, agreed not to run it again that weekend, and the results stood.
Why it matters
A device approved four times by the FIA's own technical delegate and then declared illegal by three stewards in one afternoon. The clearest evidence that pre-instrumentation enforcement was a judgement call.