F1 2016 second test session in Barcelona, day 5 | Pirelli

F1 2016 second test session in Barcelona, day 5

The teams took to the track in Barcelona in the full knowledge that they had just four days of running before heading out for free practice in Australia.
With most teams splitting the workload between their drivers, for most drivers that's just a maximum of 18 hours in the car over four days. More realistically, with stoppages and mechanical interventions, it's probably about 10 hours. And 10 hours is really not much time on which to build the rest of the season – yet that's exactly what's being asked of each and every driver here.

The big news from the first day of testing in Barcelona was Mercedes putting on the soft tyres for the first time.
As most people expected, Nico Rosberg went straight to the top of the time sheets: but then the team changed drivers for the afternoon and stuck Lewis Hamilton out. His focus was a full 66-lap race simulation, showing remarkable consistency.
Rivalry between team mates is not something that just gets switched on and off every other weekend: it exists 365 days a year, even before the season begins. And although neither driver would probably admit it, there's a point of pride to be made and a psychological advantage to be had about getting the upper hand in testing. 
In many ways testing sets the tone for the season, with McLaren having cause for optimism thanks to some interesting times from Fernando Alonso, using the final 2016-specification Honda engine with the soft tyres to go third-fastest. 
Tuesday was not only the hottest day of Barcelona testing seen so far, with track temperatures peaking up to 29 degrees centigrade, but also the most polarised – with lows of just four degrees in the morning, leading to thick layers of frost on the Pirelli motorhome. 
By the afternoon, everyone was wearing sunglasses, in conditions that were more representative of the season ahead. With favourable weather and a high level of reliability achieved already, the teams covered considerable distances as they began to ramp up performance: Rosberg setting the quickest time of the five days of 2016 testing held so far.
There were some new arrivals for the second Barcelona test, with Toro Rosso and Sauber running their 2016 cars in definitive livery, meaning that this is the most accurate picture we have seen yet – both aesthetically and sportingly – of the season that lies in wait.
A wide spread of tyres was tried out, with some teams including Williams running tyre temperature sensing cameras, which measure the temperatures the tyres reach under a variety of usage conditions. Because there are more compound choices this year, as much detailed information about tyre behaviour as possible could turn out to be a crucial strategy advantage. It was a good day for Williams, with Valtteri Bottas using the new ultrasoft to go second behind the Mercedes.
The question, as always from testing, is this one: how much of the information gained in Barcelona now will translate seamlessly into performance at Albert Park, on the other side of the world, in three week's time?