It doesn't take an expert to realise that the latest generation of Pirelli tyres are having a big impact on racing this season, yet extracting consistent performance from the rubber is proving to be a dark art.
There's no doubt that the field is closer this year, making every last tenth of performance all the more valuable, but the fact five different constructors have won the first five races shows just how dramatic the difference can be between getting it right and getting it wrong. But this is not a criticism; the racing is closer, more dramatic and more unpredictable - three things that the sport has sorely lacked at times in the past decade.
The difference is that now the teams and drivers are forced into a balancing act where they have to trade speed against degradation over the course of qualifying and the race. The same was the case last year, but this year's compounds are more sensitive to variables such as temperature, setup and the way the driver treats the tyre throughout its life span. The balancing act has shifted from walking across a river on a plank of wood to walking across it on a tightrope.
"Tyres are a very complex thing and there's a very complex chemistry involved in producing a racing tyre," Mercedes technical director Bob Bell explains. "Just because they're black and round we've taken them for granted for too long, but there's some very clever chemistry in getting them right for racing purposes and it's entirely possible within those boundaries that you can produce a tyre that requires a lot of understanding to get the best out of it."
Getting the tyre to perform within its "operating window" has become the Holy Grail to qualifying and race successes this year. If it was an exact formula then clearly there wouldn't be such an issue, but the sensitivity of the tyres means their peak performance can be a moving target between circuits and throughout a weekend.
The difference between degradation and wear
- Pirelli's motorsport director Paul Hembery explains: "Degradation is a thermal performance loss - that's from the tyres overheating essentially, taken to extremes in terms of lap time. Wear is the physical wear of the tyre which is probably easier for people to understand. The two are linked, though not necessarily in a parallel manner, but they are linked."
"If you have a very small operating band, a very small target, the people that have to try and hit that sweet spot are facing a very difficult job in order to do so," Bell adds. "Clearly that means you can have very good consistency [from the tyre], but if that consistency produces a small window then it means the user of the tyres has a slightly tougher time.
"It's more to do with how we use the tyres, how we bring them in on an out-lap for example if we're going for one timed lap and if we're going for multiple timed laps how we condition them between those laps - fast, slow, fast for example. There's that operational side to it and then there's the side of the setup of the car and what you need to do to affect the way that the tyres heat up, the way that they're loaded and to get the best out of them.
"We're fighting on several fronts. We're fighting on wear because you need the tyres to last a certain time and we're fighting on degradation to make sure they deliver the grip over the period of that life. Managing both of those is the tricky balancing act for these tyres. That's why we're seeing variability in grids and race positions this year."
The other problem is that changes in setup can solve one problem but create an issue elsewhere - rather like when you squeeze a balloon and the air goes from one area to another. The trick is to squeeze as much performance out of the tyre without stressing its limitations. Jenson Button struggled with his tyres throughout the Spanish Grand Prix weekend and on Saturday explained some of the problems he'd been having while trying to find the right setup in practice.
"We did two runs on Friday on the prime tyres, and on the first run I told the guys I had massive understeer," Button said. "We pumped the tyres up a bit more and I went straight back out and went half a second quicker just because the fronts were switched on. But forgetting the time, the balance was completely changed. So it's a tricky one to try and work out and it's obviously difficult for everyone, but I'm finding it especially difficult so it's something I need to work on."
The problem is that an upset balance can lead to higher levels of degradation as the car slides, meaning you can produce one fast lap but struggle on a longer run. So it's vital to find the balance first and foremost, but then there's the challenge of maintaining that across qualifying and the race. The teams cannot make setup changes under parc ferme conditions on a Saturday night and this means finding a balance between qualifying pace and race pace.
"You set the car up to try and deal in the best possible way with what you foresee coming in qualifying and what you foresee coming in the race," Bell explains. "The ultimate objective is to bring home the most championship points so you bias that towards what you need for the race, and qualifying is a step in that process."
But this year a change in temperature between qualifying and race can have a big effect on tyre performance. At the start of this year the Mercedes cars overheated their tyres in the dry in Australia but struggled to get enough heat into them in the wet at Malaysia. Then at the next race in China they got it bang on in cool but dry conditions. Bell says most the teams now know how to change setup to suit the temperature, but if the ambients change between Saturday and Sunday it can cause problems.
"I think it's fair to say that you can set the car up perhaps to be better in qualifying conditions because you know the ambients you expect from that and you then might be slightly disadvantaged for the race, or vice-a-versa. I think we all know the sort of things we need to do to try and account for variations in track temperature, but if those track conditions change you can be in trouble. Again that's because it's such a narrow operating window we have to get those tyres in."
The huge influence the tyres have on racing at the moment has led to some criticism, but as fans we should be relishing this period of unpredictability and exciting racing while we have it. The teams are full of intelligent and skilful people, and just as they learned quickly how to cross the river on the plank of wood last year they will no doubt become adept tightrope walkers too.
"We've closed down the range of compounds," Pirelli's Paul Hembery says, "and the cars have obviously changed as well, and you put that combination together and you have a start to the season pretty much as we saw last year - some question marks that tend to get ironed out as the season goes on and the teams get to understand better the cars, the tyres and how to get the best out of them all. I think you'll see over the next few races that that will be the case."
In the meantime, sit back and enjoy the show.