Nico Rosberg says the thin air in Mexico City means Mercedes is getting Monza levels of downforce from Monaco-style rear wings this weekend.
Mexico City is at an altitude above 2,200 metres, meaning the air is much thinner than any of the other tracks the sport visits. As a result, the cars experience less drag and produce less downforce than normal, resulting in high top speeds but also a lack of grip in the corners.
Rosberg revealed Mercedes is running as much wing as it would at the tight and twisty Monaco, where downforce is at a premium, but only generating Monza levels of drag, where teams run skinny rear wings to go as fast as possible. The downforce is also traded against cooling, and after Rosberg suffered a brake fire in the morning, he said Mercedes is right on the limit.
"It is a challenge, we are really on the edge here on the brakes," he said. "If you cool the brakes more you lose performance because you need to open up the car and you lose downforce, so you go slower. You always want to be on the edge and here specifically is quite difficult because we are quite high up - it is like a ski station in Europe!
"The air is very thin so it doesn't flow very well through the car and down the straights there is no resistance. We had the Monaco rear wing on the car with full downforce but we are doing Monza speeds, so it is quite impressive."
Rosberg said the lack of grip is not helped by the slippery track surface, but that the circuit layout is still fun to drive.
"It is unique, very slippery because the asphalt is new. It is smooth and doesn't have a lot of grip so we are sliding about a bit. It reminds me of my youth because the corners are tight, so it is a bit like a go-kart track, but it's great to drive. Going through those two stadiums, one is a fake one, but one is a real baseball stadium... I think it is an awesome atmosphere."