This weekends Formula 1 Gran Premio de España 2013 in Barcelona signals the start of the first European section of the FIA Formula One World Championship, and it will be a crucial race for every team on the grid.
This is where everyone will be bringing their big updates. Those that are up front, such as Red Bull, hope to move further ahead. Others who are a little behind, such as Lotus, Ferrari and Mercedes, will hope to be closing the gap. McLaren hope to scale their own technical mountain with major revisions here. And further back the smaller teams each have their respective hopes pinned on modifications that have been in the pipeline since the racing began in Melbourne.
Last year Pastor Maldonado and Williams stunned the F1 world with a beautiful victory over Fernando Alonso and Ferrari, but can we expect a similar sort of upset this year? Williams have a big update that they expect will put the FW34 closer to the front.
"We are working with a package for Spain and we expect it to be better, chief race engineer Xevi Pujolar says. While we could see the problem in the first races, from one place to another it was not exactly the same. So we have been catching up and trying to get the best for Barcelona.
"At the moment we think that it's going in the right direction, even though it is not going as fast as we would like. But all the parts we brought to the car we've run them, so that's good."
The odds favour Red Bull and their immediate competitors, however. But that doesnt mean that the Milton Keynes team are getting complacent, even though Sebastian Vettel won in Malaysia and dominated in Bahrain.
"Ferrari are strong, Lotus have a good car, and the Mercedes certainly over a single lap is very strong," says team principal Christian Horner. "The rest are a step behind. It's close, it's tight and I'm sure it's going to move around from circuit to circuit as we head back to Europe.
Fernando Alonso has also won a race, but remains low-key ahead of his home Grand Prix as aero chief Nikolas Tombazis says that Ferraris opening performances rate only six out of 10. At Lotus, meanwhile, it remains to be seen what effect the resignation of technical director James Allison will have in the short term, as long-serving Nick Chester moves up into that role.
Lewis Hamilton had a solid pole position here last year for McLaren before fuel issues intervened, and is optimistic that Mercedes can be a factor.
It feels like a long time since Bahrain so we're all looking forward to getting to Barcelona and starting to get into the routine of the European season, the 2008 champion says. The short break has been good however, and I've had the chance to catch up with family and friends, and also spend some time at the factory with the guys, working on our efforts to improve.
We've been boosted by the results that we've had at the start of the season and to come away from the first four races with two third and two fifth places feels like a real achievement. I'm feeling very comfortable in the car now and we know the areas that we need to improve so a lot of effort is being put in to close that gap to the front-runners. Barcelona should be a good test as we know the circuit so well having completed most of the pre-season test programme there. The weekend should be a good benchmark of the progress we have made since then.
McLaren feel the same, and this really is a crucial event for them which will demonstrate whether they have started to get the best from the troubled MP4-28.
Its been difficult for the team to make consistent progress through the first four races, but I think returning to a circuit where we undertook two of the pre-season tests will give us a useful benchmark of our progress so far, a cautious Jenson Button says.
Theres been a lot of talk about the importance of the weekends upgrades; but, as with every upgrade, theyre simply part of the series of continuous improvement that is made across the season. As always, therell be elements of it that work, elements that perhaps work in a different way to what wed anticipated, and elements that dont work, or perhaps require further work. Thats life in modern Formula One. So Im pragmatic about what well discover. Of course, Im hopeful that itll move us a step closer towards the destination.
Team boss Martin Whitmarsh is hoping for a less frenetic race between his drivers here, after they made their peace in the aftermath of their tough scrap in Bahrain.
As with last year, form at the start of the season is still somewhat volatile and unpredictable, he suggests. Last years Spanish Grand Prix saw an unexpected but worthy winner in Pastor Maldonado, and while it would be difficult to see another left-field runner emerging as a contender for victory, the formbook is still hard to read.
We are pushing ahead to develop MP4-28, and will be hoping for a productive weekend that will allow us to gather a useful data set for the races ahead.
Sauber have revised aerodynamics to boost the C32s thus-far disappointing form, while Caterham have the rest of the major update that looked so promising in Bahrain. They expect big things from it.
The 4.655-kilometre Circuit de Catalunya features 16 corners, the majority of which are right-handers which put the left-front tyre under the greatest strain. But the rears also take a beating coping with the demands of strong traction exiting the slower corners. Throw in the abrasive surface and the tendency towards high ambient temperatures, high lateral loads around 4g, with spikes of 5 under braking into Turns 1 and 10, and tyre wear is always high.
Pirelli are bringing their orange hard compound and white medium compound tyres, but in a change from previous 2013 races the former will be closer to the 2012 tyre with the aim of opening up even more possibilities for strategy.
Teams will also get an extra set of prototype hard tyres for free practice to encourage them to run throughout the sessions instead of opting to conserve tyres for the rest of the race weekend. These are a specially-created compound with the emphasis on durability and to distinguish them they wont have any colour markings.
Were introducing a revised version of our hard tyre in Spain, which is closer in characteristics to the 2012 tyre, Pirellis motorsport director Paul Hembery explains. This new tyre gives us a wider working temperature window - although it delivers a little bit less in terms of pure performance - but it should allow the teams to envisage an even wider variety of race strategies than before in combination with the other compounds, which remain unchanged this year. This is a decision that weve come to having looked at the data from the first four races, with the aim of further improving the spectacle of Formula One. In fact this is almost a tradition with us now, as we also introduced a revised version of the hard tyre for the Spanish Grand Prix in 2011, which was our first year in the sport.
Wed expect the medium tyre to still be significantly faster and this is the one that the teams are likely to qualify on, whereas the hard is likely to be the preferred race tyre.
As for the extra sets of prototype hard compound tyres for free practice, we wanted to encourage all the teams to run as much as possible right from the start, especially with the rookie drivers, to give fans the spectacle they deserve to see.
In a change to 2012, the track will feature two DRS zones. The first is between Turns 9 and 10, with the detection point midway between 8 and 9. The second is on the start-finish straight, with detection between Turns 15 and 16. In the only other circuit revision since last year, the leading edges of the combination kerbs on the apices of Turns 13, 14 and 15 have been chamfered to remove a step.
The weather in Montmelo is expected be dry and reasonably warm throughout the Grand Prix weekend, with ambient temperature highs of around 18 degrees Celsius. Sundays race will run over 66 laps, or 307.104 kilometres (190.834 miles), and will start at 1400 hours local time, which is two hours ahead of GMT.
