He signed an extension to his Red Bull contract for the season prior to the 2010 Canadian Grand Prix, having agreed with the team to sign one-year contracts late in his career for ability and quality assessment although he considered switching teams or retiring if Red Bull did not renew his contract. Webber had a worse mental state prior to the season because he had been ready for a championship win and then retire partly to stop all negativity in his racing career and him having "reached my ultimate destination". His objective was to extract the maximum from himself and his RB7 car featuring the kinetic energy recovery system (KERS) and the drag reduction system device and produced a high level of rear-end grip from an exhaust-blown diffuser. Webber's car was hindered by intermittent KERS failures that Red Bull rectified and he was frustrated with the quickly degrading Pirelli tyres losing their performance when a driver was in the aerodynamic turbulence of another car. He made fewer pit stops by being on the same strategy as other drivers after previously having to stop more often earlier in 2011 from being involved in competitive racing. Webber made slower starts due to the car's ballast distribution compromised by the KERS' additional weight and exacerbated by him weighing more than Vettel.