The European leg of the 2014 Formula One season starts on 11 May with the Spanish Grand Prix at the Circuit de Barcelona-Catalunya.
After the four "flyaway" races at the start of the year, many teams have targeted Spain to introduce substantial updates. Everyone from Mercedes to Caterham will have at least some new parts, and at least one team—Sauber—will have a massively updated car.
The battle in the midfield is especially close, and a small shakeup in the order is almost inevitable.
But the gap at the front between Mercedes and the rest is more substantial. The German constructor has won all four races so far, claimed all four pole positions and set all four fastest laps.
Their closest challengers are probably Red Bull. The Austrian team have the best chassis but are being let down by a weak Renault power unit.
At this stage, their best chance of competing with Mercedes is at circuits which favour downforce-generation over straight-line speed.
As luck would have it, we're heading to one of those for the next race.
The Circuit de Barcelona-Catalunya (which sounded much better before they gave it a "double-barrelled surname") is one of the best all-round tests of a car's aerodynamic performance on the calendar.
It features a high number of quick and medium-speed corners, and the modifications made between 2004 and 2007 added a couple of low-speed turns. Several of the corners fall into the "long" category, and these are the ones which really give the aerodynamics a workout.
There are two straights, but only one, the pit straight, is of a decent length.
Catalunya is a circuit where cornering speed really takes centre stage—so can Red Bull compete for the win in Spain?
Their team principal, Christian Horner, believes they have to. Speaking to Sky Sports F1 last week, he said:
We've got to if we're going to make a championship of it. We've got to take the fight to them. We're going to give it everything. I believe we can take the fight to them, we just can't concede too much more ground.
We were 22kph slower on that kilometre straight [in China], that represented almost 100 metres that we were giving away on the straight.
That's where we've got to improve—it's quite simple. We know where we've got to fix our issues and hopefully there are some steps towards that in Barcelona.
Red Bull have tended to be slower on the straights for several years, sacrificing top-end speed for downforce in a quest for better overall lap times.
The trend has continued into 2014, but the gap between Red Bull and their rivals has grown.
Speed trap data on Formula1.com from free practice in China (the last dry session before the race) suggests a gap of around 11 kilometres an hour in the dry. Race data from the FIA—which is less reliable due to the frequent use of DRS and slipstreaming—produces a figure of 15 kilometres an hour.
Part of this is due to Red Bull running more downforce, as they always do. But mostly, the responsibility for closing the gap rests on the shoulders of the team's engine supplier, Renault. The French company's "powertrain" (the engine and associated parts) simply isn't as good as the Mercedes effort.
Even at a circuit like Catalunya, powertrain performance will still have a significant impact.
That isn't good news for Red Bull, and they can't expect any miracles. Speaking last week (h/t ESPN), Renault's head of track operations Remi Taffin said:
I would not say optimism [for the change in circuit type], we are still on realism. It's fair to say that coming into Barcelona or Monaco it's not going to be massively power sensitive, but it is going to be massively energy sensitive.
In the race it's always going to be important to have the power unit working right. At least we have three weeks [between the last race in China and Spain] to keep on doing the job, and then maybe ahead of Montreal having something that is very close to 100 percent.
It sounds like progress has been made, but Taffin admits they're still at least a month away from operating close to their full potential.
And the Red Bull isn't that much better in the corners than the Mercedes.
We can expect the gap to close somewhat. Renault will have made some progress, and whatever advantage the Mercedes powertrain retains will be slightly reduced by the nature of the circuit.
There's a chance the W05 might revert to the habits of its predecessors and suffer excessive tyre wear at a circuit which is known to be tough on the rubber.
But given the size of the advantage enjoyed by Mercedes—as of China, it looks at least a second a lap in race trim—closing it entirely is out of the question.