Kimi Raikkonen gave the new long-wheelbase Lotus E21 its debut during the first free practice session for the Italian Grand Prix. The wheelbase has been lengthened by around 100mm, which is achieved by moving the front wheels forward relative to the rest of the car.
This long-wheelbase package (LWB) comprises revised front suspension, a longer nose and an extended floor.
With only enough parts to run one car in the revised specification, it is expected Raikkonen will run the LWB car for the full weekend while teammate Romain Grosjean runs the conventional car with Monza-specific updates.
The idea for the change to the LWB car came from the vehicle dynamics department, which is a surprise as these days the wheelbase is largely an aerodynamic factor. Lotus has found a handling advantage in extending the wheelbase and altering the car's weight transfer characteristics. With the wheels moved forward, the aero department has also been able to find some performance gains from the front tire wake being further from the sidepods.
Although a wheelbase can be lengthened by extending the gearbox or altering the rears suspension, Lotus opted to angle the front suspension forward as this has fewer knock-on effects on the rest of the car.
The front axle line is used as a reference point for the position of the front wing and the T-Tray splitter under the car. Therefore, the front wing and leading edge of the T-Tray also had to be extended forwards by the same amount as the wheelbase change.
Visually, the two cars can be differentiated by the longer nose and the front track rods which are now at right angles to the car's centerline and not swept back as on the conventional car.
While the change to LWB might be seen as an advantage on a fast track like Monza, the weight shift and aero advantage is a larger benefit on conventional tracks.
If the change is successful, it will be applied to the cars for the rest of the season.