Mercedes has claimed that the new aero package that they brought to the second test in Barcelona has yielded a "considerably quicker" race simulation. However, some problems are still lingering for the defending world champions.
On day two of the second test, Mercedes managed a massive 176 laps between the two drivers, which was more than any other team.
James Allison, the technical director had some interesting comments on tyre wear.
"We did set-up work in the morning with Valtteri and continued with this in the early afternoon with Lewis, yielding some good results for both drivers. The race run in the afternoon, although quite considerably quicker than the last race simulation we made, was marred by front graining - something which we think, looking up and down the pit lane, could be a feature of the year.
"We need to make progress on graining resistance in the next couple of days, in order to make sure we have a good way of handling it by the time the racing season begins."
The Silver Arrows have struggled with tyre wear in the past, but it will be interesting to see whether they are the only ones as we go into the 2019 season.