The pre-season testing period is a nervous time for all the F1 teams and drivers - and also for the tyre suppliers Pirelli, who need to be sure that their planned new compounds for 2013 will be up tot he job.

Poor weather conditions at last week's test session in Barcelona resulted in higher than expected degradation for the tyres, as Pirelli's motorsport director Paul Hembery conceded.

"The last test at Barcelona was affected by bad weather, which meant that we experienced more degradation than usual due to the tyres not being able to operate within their intended working range," he said. "Hopefully this time we will find conditions that are slightly more representative, which will allow the teams to collect more relevant data."

All the F1 teams return to the Circuit de Catalunya this week for a further four days of testing, commencing on Thursday and running over the weekend. After that, there will be no more track time available to them until the first free practice session in Albert Park, Melbourne ahead of the Australian Grand Prix on March 17.

"At this stage of testing it is always difficult for the teams and drivers to know what to expect from the first race as conditions are not always representative," said Hembery. "The fact that we're going back to Barcelona gives them all an excellent known baseline from which to operate."

Much of the early part of the 2012 season was dominated by tyre wear, with teams struggling to find the 'sweet spot' of last year's compound that got the grip sufficiently turned on without causing major tyre degradation. Hembery said that Pirelli considered that normal, and pointed out how things had changed as the season progressed and teams got more data to work with.

"Past experience from the last two years shows a big reduction in tyre degradation over the course of the season," he said. "Roughly half the degradation seen in winter testing. This year, we think that degradation will be higher than it was in 2012, and we estimate a degradation rate of around 0.15 to 0.18 seconds per lap in race conditions for the hard compound in Barcelona.

"These 2013 tyres are quite different to their predecessors, both in terms of compound and construction, which makes the work that will be carried out over the next few days even more essential," he added.

Each car testing at Barcelona will have up to 35 sets of Pirelli's new P Zero supersoft, soft, medium and hard compounds available for the four days. In total, each team is allowed 100 sets of tyres per car for testing purposes over the course of a season.

Pirelli get to select 20 of the sets that a team will use, while the teams can request 15 of their own choice. Any sets of tyres not used at the previous Barcelona test can carried forward and used this week.

Barcelona is a popular choice for testing, as it represents the best 'everyman' circuit available to teams trying to find a good car that will work across the entire season.

Just under 60 per cent of the lap is spent at full throttle, with the cars at top speed for around 16 seconds on the straight. A medium- to high-level set-up is required, with high tyre and brake wear usually the case on the abrasive Circuit de Catalunya track surface.

The track will also be used for the Spanish Grand Prix May 12, so the teams are able to get a jump start on race strategy: Pirelli estimates that the tyre wear will lean toward a two or three stop strategy for the race, a performance outcome in line with the requests of the teams and FIA.

Pirelli added that even though the initial data collection process was hampered by cold weather last week, they were happy that all the initial indications point to this being the case for Spain's Grand Prix.