Technical talk - Service area flat-patch.

What is the flat-patch platform? What is it used for? Why is it there? Find out here...

Set up using spirit levels, the 'flat patch' provides an area that is 100 per cent level.

This is necessary to achieve accurate set ups of the team WRC cars, including the camber settings, corner weights, wheel alignment and suspension geometry. The ground in the service parks is never totally even.

Electronic scales on the flat patch lie under each wheel. These provide accurate readings of each corner weight and the overall weight of the Subaru Impreza WRC2003, so technicians can check that it's correctly balanced.

The technicians put ballast in the front of the car to take into account the weight of the drivers. The Subaru drivers and co-drivers exact weights are regularly monitored by Prodrive's Human Performance Department and communicated to the rally team.

While front and rear corner weights of the Impreza differ (front corners being heavier due to the weight of the engine), opposite corners of the car should be equal.

To re-adjust the balance of the car, technicians alter the damper platform height of each corner of the Impreza to amend the ride height and re-distribute the weight.

The flat patch is also used to check the camber settings of the wheels. To check these, the car is driven onto the patch, vertical bars are attached to the centre of each wheel and an electronic measuring device is held up against these to obtain an exact figure.

Made of aluminium and fully portable, the flat patch is used by the 555 Subaru Rally Team at each round of the WRC, including Sweden, where temperatures can be below freezing, and Greece, where temperatures can reach up to 40?C.