2009 F1 Regulations
KERS, Slicks, and the Double Diffuser
The FIA stripped back the aero, bringing in a wider and lower front wing, a narrower and taller rear wing, and banning the forest of winglets and chimneys that had grown over the preceding years. Slick tires returned after 11 seasons of grooved rubber, and KERS gave F1 its first taste of hybrid power: 60kW available for 6.67 seconds per lap. The headline story, though, was what the FIA didn't intend: an ambiguity in the diffuser regulations that Brawn GP, Toyota, and Williams interpreted as allowing a double-deck diffuser, producing significantly more rear downforce than their rivals.
Typical Engine
Configuration
V8
Capacity
2.4L
Aspiration
Naturally Aspirated + KERS
Power
~740 hp + 80 hp KERS boost
What Changed
Tires
Grooved tires (4 grooves)
Slick tires return after 11 years
Front Wing
Narrow, high mounted
Wide, low, driver-adjustable flap
Rear Wing
Wide, complex profiles
Narrow, tall, simplified
Diffuser
Standard flat floor diffuser
Taller diffuser (double diffuser loophole)
Bargeboards
Large and complex
Restricted in size
KERS
No hybrid system
60kW boost for 6.67s per lap (optional)
Car Weight
605 kg
605 kg (unchanged, +KERS weight penalty)
Refueling
Mid-race refueling allowed
Banned from 2010 (phased in next season)
Aero Appendages
Winglets, chimneys, turning vanes
Most banned, cleaner bodywork
Impact on Racing
- Brawn GP, a team that nearly didn't exist after Honda's withdrawal, won both titles on the back of the double diffuser advantage
- Red Bull and Newey pivoted quickly, developing their own double diffuser and beginning the run that led to four straight titles (2010-2013)
- KERS uptake was inconsistent: the system weighed ~25 kg, and several teams calculated the weight penalty wasn't worth the 80 hp boost
- Slick tires restored mechanical grip lost since 1998 but the narrower rear wing reduced peak downforce, shifting the aero balance forward
- The driver-adjustable front wing flap was the FIA's first experiment with driver-controlled aero: the concept evolved into DRS by 2011
What changed in the 2009 F1 regulations?
The FIA stripped back the aero, bringing in a wider and lower front wing, a narrower and taller rear wing, and banning the forest of winglets and chimneys that had grown over the preceding years. Key changes: Tires: Grooved tires (4 grooves) to Slick tires return after 11 years; Front Wing: Narrow, high mounted to Wide, low, driver-adjustable flap; Rear Wing: Wide, complex profiles to Narrow, tall, simplified; Diffuser: Standard flat floor diffuser to Taller diffuser (double diffuser loophole).
How did the 2009 regulations affect racing?
Brawn GP, a team that nearly didn't exist after Honda's withdrawal, won both titles on the back of the double diffuser advantage. Red Bull and Newey pivoted quickly, developing their own double diffuser and beginning the run that led to four straight titles (2010-2013). KERS uptake was inconsistent: the system weighed ~25 kg, and several teams calculated the weight penalty wasn't worth the 80 hp boost.
What engines did F1 cars use under the 2009 rules?
V8, 2.4L, Naturally Aspirated + KERS, around ~740 hp + 80 hp KERS boost. Notable engines: Mercedes FO 108W, Ferrari 056, Renault RS27, Toyota RVX-09.