ERJ staff report (TP)
Zottegem, Belgium − Even though it's been known for a while, recent thermal imagery has shown the true effects of rim coatings to manage tire temperatures, reported Steven De Grotte for F1Technical.net.
The coatings were first photographed on Mercedes AMG's Advanti wheels, featuring dimples on the inside of the rim as well. Later on, Red Bull was confirmed to also use a similar treatment on their OZ Racing wheels, although in their case the inside of the wheels features grooves rather than dimples. Ferrari meanwhile are said to be coating their OZ Racing wheels as well.
It was recently also found out that the black coating is actually Polysil, produced by Nanoprom near Sassuola, Italy. It is a solvent based product containing polymers of silicium, mainly designed to protect all sorts of materials against surface friction. The product is typically sprayed to create a film of only a few microns to reach a hardness of up to 9H. This is achieved mainly by letting the product fill up tiny gaps in the imperfect wheel surface, creating a very smooth result that may also help to reduce turbulence within the wheel.
Its black colour however is interesting for teams as that will help for the rim to absorb heat from the brakes into the Magnesium alloy wheel itself. As the rim itself has a very high thermal conductivity, the heat going into the metal is then spread rapidly throughout its entire body and partially transferred into the tire through the tire bead. As a result, it is possible for teams to keep the tires at a more constant temperature, reducing the rapid drop of temperature of the tires when running on long straights. Instead, with the rim properly warmed up, the tire wall is kept warm, preventing the tire's thread to cool off too quickly. The net result is more grip at turn-in as the tires haven't cooled down as much as without the treatment.
Even though it is still early days and nobody knows yet what will be the operating temperatures of the new 'conservative' Pirelli tires, it is nonetheless very likely that this technology will continue to be used in 2014. Even more so, with Nanoprom citing the possibility to use their coatings on composites and aluminium, it is nearly sure that it is or will be used on parts of the engine as well.
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