Understanding F1: Why do teams tell drivers to pick up the marbles after the race? All about dirty rubber on tires

There are several rules and regulations that all F1 teams have to abide by. Since it is a highly technical sport, every metric is measured and noted. The FIA usually looks at several data, including the weight of the car and the driver before and after each race.

The overall weight of the car and driver drastically decreased after the race. Hence, to prevent them from losing too much weight and getting a penalty from race control, teams have found a clever way to increase their car's weight.

As F1 cars race around the track, their tires are subjected to blistering. This is a phenomenon where small chunks of rubber break off from the tire surface due to increased internal temperature.

Along with blistering, graining also occurs where parts of the rubber heat up and create an uneven layer on the tire surface. Not all rubber particles during graining are fused back into the tire, and occasionally, they break away from the tire surface as well.

Due to these two phenomena, loads of rubber particles, or 'marbles', lay around the track, right beside the racing line. Normally, we don't see any rubber particles on the racing line since drivers constantly pick them up while racing.

As the race comes to an end, drivers lose weight due to the loss of body fluids, and the cars lose weight due to fuel burn. As a result, they may go below the minimum weight limit set by the FIA and take a penalty.

Teams, however, usually ask drivers to purposefully pick up chunks of rubber laying around the track to gain a bit of weight to stay above the minimum weight limit. These kinds of requests from teams are usually made after a race ends since these sticky rubber chunks create an uneven surface on the tire which hampers the car's grip.

This tactic has been used by F1 drivers and teams for a very long time. Even during the early 2000s, when tires had grooves on them, drivers used to pick up rubber particles on their tires to stay above the minimum weight limit.

Of course, the FIA are well aware of this tactic used by the teams, but they haven't created any rules to negate or disallow it.

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F1 to introduce new tire compound for 2023

After the 2022 F1 season came to an end, all the teams took part in a post-season testing session where they tested Pirelli's new tire compounds for the next season. The Italian tire-makers will be introducing a sixth dry weather compound called 'C0' which will be based on last year's C1 tire compound.

Simone Berra, Pirelli motorsport engineer, explained how the new C1 tire will offer more grip and also gave an overview of other dry tire compounds for the 2023 F1 season. He said:

"The new C1 was tested in Texas and it offers more grip, as the old version of that tyre wasn't as grippy. The current C2 to C5 tires remain exactly the same in terms of composition."

The addition of a new C1 compound tire and the old C1 converting into C0 will give teams more options to choose from during race weekends. Additionally, Pirelli is also working on new full-wet tires, which will be much more useful than last year's.