Mexican Grand Prix stewards have cleared Mercedes over its wheel design, following a clarification request from the Formula 1 team.
Article 12.8.1 of the Technical Regulations permits “spacers on the inboard mounting face of identical specification on all wheels for the same axle."
Mercedes has run such a spacer on its rear wheels and in order to reduce the heat flow across the junction between the axle and the wheel, they have a number of small holes and grooves.
Following its fourth straight victory in Japan Mercedes sought clarification from the FIA’s Technical Department over whether the design contravened Article 3.8 of the Technical Regulations.
That regulation states that “any specific part of the car influencing its aerodynamic performance must remain immobile in relation to the spring part of the car.”
The Stewards noted that “the question was whether the air passing through these holes and grooves [on the wheel] violated this provision.”
The FIA’s Technical Department concurred with Mercedes that the part would be in compliance with the regulations, though cautioned that such a stance was advisory in nature, and that it is up to the Stewards, and ultimately the FIA International Court of Appeal, to offer binding interpretations.
Mercedes did not run the new design in Austin last weekend and missed out on victory after struggling with rear tyre wear, though was also stymied by weight imbalance, ostensibly caused by set-up problems after pre-race changes on both cars.
Mercedes therefore requested further clarification, this time from the Stewards, over its interpretation of the regulation and legality of the part.
Stewards backed Mercedes’ interpretation of the rules though cautioned “only with respect to the points raised in Mercedes’ request” and that its jurisdiction extends only to this weekend’s Mexican Grand Prix.
Stewards also declined to make a “generalised interpretation” of Article 3.8, and stressed that “alternative design options would have to be considered separately.”
Stewards added that “the opinion of the FIA Technical Department is correct when they state:
“Regarding the legality of the holes in the spacer:
“1. To determine whether the holes have an aerodynamic influence, one has to consider their size, shape and function. Small holes will tend to have primarily a cooling function, and while we can at times consider cooling to be an aspect of aerodynamic performance, we feel that cooling of very localised areas (as in your design) can be acceptable.
“2. The space is specifically part of the wheel assembly, so provided its main function is that of a spacer, we feel that having some localised bleeding of the flow for cooling can be acceptable. The fact the spacer rotates is inherent in its function, in much the same way that the wheel rim spokes rotate.
Hence for the above reasons we consider the spacer geometry you have adopted to be permissible, although we would reserve [the] right to judge alternative geometries, and to change this view if (for example) the spacer were to grow beyond its primary function (that of a spacer) and if the holes were to become big enough to have a more significant aerodynamic effect.”
It means that Mercedes is permitted to run the wheel design so long as it follows the stewards’ understanding of the aforementioned opinion of the FIA Technical Delegate.
Stewards have reminded competitors that they have the right to appeal their decision.
