Wet conditions on Friday mean relaible tyre data is at a premium ahead of the U.S. Grand Prix. That often leads to an unpredictable and exciting race as teams learn about the behaviour of the tyres in real time, but there is still little doubt it will be a one-stop race.
Within the top ten there will be a mix of ultra-soft and super-soft starting tyres, with Kimi Raikkonen the only one of the top five top opt for the softer of the two compounds. Data from final practice suggested there was a minimal amount of degradation on either tyre, although without long-run data from Friday it is difficult to put a number on it. There is likely to be a degree of flexibility over when to pit for both starting tyres, but naturally the super-soft will give a wider pit window and could be used to adopt either overcut or undercut strategies.
The main advantage of starting on the ultra-soft is that it should offer better grip off the line and that could be enough to give Raikkonen the lead going into Turn 1. However, after five laps or so the super-soft is expected to be the better tyre and a number of drivers reported that the red-striped tyre offered greater stability through the high-speed corners.
"In theory we should be able to have a longer first stint than Kimi," Mercedes driver Valtteri Bottas, who starts from third on the super-soft, said. "I think at the start, with the softer tyre, Kimi should have the upper hand but it depends on the temperature of the tarmac, but the difference [between how good the start is] can be in metres.
"After two or three laps there is basically no lap time difference between the compounds and maybe after five laps we can start to have the edge."
Another thing to note in the battle between Mercedes and Ferrari is that the red cars had much better straight-line speed in qualifying. That could partly be down to a power advantage, but it also seems as though the Ferraris are running less rear wing, which will offer an advantage on the straights by reducing the amount of drag. However, less rear downforce is also likely to put extra strain on the tyres, especially as the Circuit of the Americas is a rear-limited circuit when it comes to tyre degradation.