Mercedes again the team to beat in F1 2015
Two of Formula One's top drivers have made lucrative moves to new teams in 2015, so fans might think there will be a shake-up to last season's established order.
They would be wrong.
The evidence of preseason testing strongly suggests the fight for this year's championship will again be a case of Mercedes vs. the rest.
''We want to be better this year. We want to try and dominate even more,'' reigning champion Lewis Hamilton said ahead of the season-opening Australian Grand Prix in Melbourne on March 15.
The switch of four-time F1 champion Sebastian Vettel from Red Bull to Ferrari, and Fernando Alonso from Ferrari back to McLaren, will provide interesting subplots, but the main narrative again looms as Hamilton vs. Mercedes teammate Nico Rosberg.
Hamilton got the upper hand last season, winning six of the last seven races to hold off the stern challenge from Rosberg and secure his second championship. When his confidence is up and his car performing, Hamilton is tough to beat, but Rosberg is taking encouragement and motivation from the close margins that separated them in 2014.
''All the difficult times have made me stronger,'' Rosberg said. ''I need to find small steps to beat him. And I am going for it.''
Mercedes became the dominant force last year as F1 introduced V6 hybrid engines. As one of only two teams to design both the engine and the accompanying chassis and aerodynamics - Ferrari is the other - Mercedes enjoyed a significant advantage.
With this year's regulations being only incrementally different to last year, have the other teams been able to catch up? Ferrari and Renault-powered Red Bull are the top candidates given their spending power, but the evidence from testing was not convincing.
Honda returns to F1 as engine supplier to McLaren - a combination that saw the team dominate the sport from the late 1980s in the era of Ayrton Senna and Alain Prost. It is Honda's third entry into F1.
It will be a game of catch-up for Honda against established engine suppliers Mercedes, Renault and Ferrari. McLaren's predictable teething problems were evident in a succession of technical issues through testing. Unless those glitches are rapidly resolved, it looks like a season that will test the patience of experienced drivers Alonso and Jenson Button.
Alonso returns to McLaren in very different circumstances to his unhappy season with the team in 2007. Back then, he was coming off two successive drivers' championships and felt entitled to the undivided backing of the team. Instead, Alonso had to battle then-rookie teammate Hamilton throughout the season and at year's end he returned to Renault.
Alonso will miss the opening race after suffering a concussion in preseason tests, but is expected to be fit for the second Grand Prix in Malaysia.
Ferrari hopes Vettel, who won four successive drivers' titles with Red Bull from 2010-2013, can invigorate the team in the same way his German compatriot, Michael Schumacher, did when he arrived as a world champion a couple of decades ago. Vettel also arrives at Ferrari with something to prove after a chastening 2014 when he was outperformed by younger teammate Daniel Ricciardo.
The Australian won three races - the only non-Mercedes driver to take the checkered flag. It was a significant vote of confidence in Ricciardo that the team chose not to pursue another big-name driver for this season, instead hiring young Russian Daniil Kvyat from feeder team Toro Rosso.
''Our target is to close the gap down and put Mercedes under as much pressure as we possibly can,'' team principal Christian Horner said at Red Bull's season launch.
Red Bull and Toro Rosso will be the only teams using the Renault engines this year, as Lotus switched to Mercedes power after a horrendous 2014. Lotus retained the same driver pairing in Romain Grosjean and Pastor Maldonado, so will be counting on the new power-train to make the difference.
Sauber has taken the opposite approach to fix its problems: retaining Ferrari engines but changing drivers. Out went Adrian Sutil and Esteban Gutierrez and in came ex-Caterham driver Marcus Ericsson and Brazilian Felipe Nasr.
Ericsson and Nasr may be inexperienced, but that's nothing compared with the drivers at Toro Rosso, where 20-year-old Carlos Sainz Jr. will make his debut in Melbourne alongside 17-year-old Max Verstappen. Both are sons of accomplished drivers: former rally great Carlos Sainz and ex-F1 driver Jos Verstappen.
Williams, which was much improved in 2014 and is coming off a good preseason, has retained the same driver pairing in Felipe Massa and Valtteri Bottas, while Force India has kept faith with Sergio Perez and Nico Hulkenberg.
The Caterham team has dropped out of the sport after financial collapse, but Manor Racing - formerly Virgin, then Marussia - has been rescued from a similar fate this month by new owners, and is racing against time to be ready for the start of the season.