Following on from one slightly controversial innovation around the exhaust of the Williams FW35, it seems Williams are on a bit of a roll with new ideas as we take a look at the newly designed front wheel rims of the car.
On closer inspection of the wheel rims everything looks normal until you get to the wheel nut, which is actually hollow and forms a duct through the front axle, connecting to the front brake ducts. To find the reason why they have done this, we have to first go back to the Canadian Grand Prix of last season.
After some technical meetings by the FIA at the 2012 Canadian Grand Prix, it was announced that Red Bull would have to seal some holes on the front wheel rims of the RB8. These holes were actually producing an aerodynamic effect by feeding airflow through the front brake ducts, through the front axle and to the outside of the front wheels through these holes in the wheel rim. The reason for this is to try and reduce drag created by the front wheels by redirecting airflow into the wake of the front wheels, away from the tyre itself which is a high source of drag, and produce a “cleaner” airflow going rearwards to the rest of the car. However, because the holes were incorporated into the wheel rim they rotated with it, which is possibly why it was declared a “moveable aerodynamic device” – something which is against the regulations.
Back to Williams and their new wheel nut design, this is essentially performing the same function as what Red Bull were trying up to the Canadian GP. Airflow is redirected via the front brake duct, through to a hollow duct that allows airflow to escape via the open-ended wheel nut to the outer edge of the front wheels. The difference here though is because the effect is produced via the wheel nut this does not rotate or move, therefore making this legal. The only downside to this is the front brake ducts have to be larger to make this work, which will produce more drag, so it is a bit of a balancing act.
It is worth noting that wheel rim designs are submitted at the start of the year and are homologated (they cannot be changed during the season). As this is produced via the wheel nut and the front axle, it will be interesting to see if other teams try to make this work within their existing wheel rim design.