How Brazilian MotoGP pre-race changes forced teams to adapt fast

The last-minute change to the Brazilian MotoGP race distance due to ‘track degradation’ didn’t just affect tyre choice.

The reduction in length from 31 to 23 laps prompted some riders to switch from the medium to soft rear tyre, while others at the back of the grid complained they were informed too late to do the same.

Most ultimately stuck with the planned medium rear tyre.

However, the latest edition of the Inside Ducati YouTube series shows that tyre pressure and engine maps were the biggest concern for Ducati Corse engineers.

“The tyre pressure? We can’t change the pressure,” says one Ducati engineer on the grid upon hearing of the new race distance.

There were around five minutes to go when teams were informed of the race distance change.

MotoGP's 'Standard Start Procedure' requires: 'All adjustments must be completed by the display of the 3-Minute board. After this board is displayed, riders/teams who still wish/need to make adjustments must push their machine to the pit lane':

“With the standard procedure, we can’t touch the bike… We can’t do anything. We can’t do the maps," the Ducati discussion continues.

“We have to do it on the grid. You have to uncouple the maps…”

Tyre pressure

To avoid a post-race tyre pressure penalty, riders must stay above the specified minimum of 1.8 bar at the front and 1.68 at the rear for 60% of the grand prix distance. 

Over 31 laps, that allows up to 12 laps to be under pressure. But at 23 laps, that margin shrinks to nine.

Teams calculate a starting pressure below the minimum, which then rises once the tyre is up to full racing temperature, while estimating factors such as the amount of hot, dirty air behind other machines.

Since the time window to get a tyre up to full temperature is roughly the same regardless of race distance, a much more generous lap threshold of just 30% above the minimum applies in shorter Sprint races. Hence the concern on Sunday’s grid.

Dashboard warning systems that alert riders about whether they are on course to meet the minimum pressure percentage may also have required recalibration for the new distance.

Maps

In terms of engine maps, a shorter race meant riders could now use more fuel per lap without running dry before the chequered flag. 

Likewise, those sticking with the medium rear tyre (all chose the hard front) could afford to be more aggressive in terms of wheel spin/tyre wear, influencing map settings or choice.

Ducati team manager Davide Tardozzi was seen briefly seeking out MotoGP SEG’s Carlos Ezpeleta on the grid on his way back to the team garage.

"They told me with four and a half minutes to go," Tardozzi reported to senior management, including Ducati Corse general manager Gigi Dall'Igna, who remains typically stoic.

Ducati's reigning champion Marc Marquez went on to finish the grand prix in fourth place after being caught out by the deteriorating track surface during a podium battle with Fabio di Giannantonio.

Team-mate Francesco Bagnaia crashed from eleventh at half-race distance.