FIA's List of Proposed Rules Changes

1. Aerodynamics (2005)

Diffuser height limited, front wing raised, rear wing element moved forward and changes to the bodywork immediately in front of the rear wheels. Together, these changes are estimated to reduce downforce on a current car by at least 25%, but reduce drag by less than 4%.

Explanation: lower downforce will reduce speeds, particularly in fast corners, and slightly increase braking distances, while the small reduction in drag will have a minimal effect on straight-line speeds.

2. Tyres (2005)

A driver may choose from two types of tyre, as in 2004. He will then have two sets of his chosen tyre, one for Friday and Saturday practice, the other for qualifying and the race. A damaged tyre can be replaced during the race (taken from the first set), but the car cannot be refuelled at the same time as the damaged tyre is changed.

Explanation: a tyre which must last 350 km rather than 80 km will have less grip, reducing cornering speeds, increasing braking distances and possibly producing less tyre debris or "marbles".

3. Engine (2005)

One engine to last for two race weekends.

Explanation: both peak and average power will be less than for an engine with a shorter life.

4. Engine (2006)

2.4 litre V8 (90º) with maximum bore diameter, fixed cylinder spacing, minimum crankshaft centre line height, minimum weight and minimum height of centre of gravity. Direct fuel injection, variable geometry inlet systems, variable geometry exhaust systems, variable valve timing and variable valve lift systems all prohibited. Only one spark plug, one coil and one injector per cylinder. Exotic materials banned.

Explanation: a 20% reduction in capacity will produce a corresponding drop in power. Constraints on design and the use of materials will significantly slow the rate of power increase and reduce the scope for using engine design to improve chassis characteristics. Keeping existing cylinder sizes retains many current engine components while keeping engine revs close to current levels.

5. Other engines

During 2006 and 2007, teams which cannot obtain a 2.4 litre engine will be able to use a 3 litre V10 with power restricted by means of a rev limit fixed by the FIA.

Explanation: this will ensure that all teams (including new entrants) have access to a competitive engine, even if supplies of the new 2.4 are initially restricted.