Arguably the most interesting tyre story at pre-season testing is not the new compounds, or the change in construction, but the resurfaced track.

According to Pirelli, this new surface is approximately three times smoother than previous years, which is going to have a huge affect on tyre performance, completely changing the team’s testing strategy.

Traditionally, tyre testing at Barcelona is largely unrepresentative. With ambient temperatures rarely getting above 16°C, the resulting track temperatures are never enough to get the tyres properly working within their working range. Add to this the fact that the Barcelona circuit was relatively rough, with the lateral loads in Turn 3 destroying the front left, the drivers have to spend most of their lap managing ‘cold graining’.

This is essentially where the compound is not warm enough and becomes relatively brittle, resulting in a lack of grip and as the car slides, the surface of the tyre begins to tear. The end result is a much finer graining pattern than conventional graining but this still reduces grip significantly.

The new surface was only completed at the end of January this year, and at the beginning of February, Pirelli measured the macro and micro roughness of the track.

‘The macro roughness in particular is much smoother because when the tarmac is new the aggregate is very close and there is a lot of bitumen,’ explains Mario Isola, Sporting Director at Pirelli. ‘Since our first measurements, they have tried to get a lot of cars running on track, organising a lot of track days and we were here for some GT testing two weeks ago. On the last day, it was dry and the level of grip was quite high which is common from what we’ve seen over the last few years with resurfaced tracks. We measured the track again at the weekend and there were no big differences.’

Aside from the obvious, that a smoother track will provide more grip resulting in less degradation and wear, there are also a range of other factors that can affect tyre grip. For example, the level of bitumen on resurfaced tracks is initially quite high, and it can take quite a lot of track running to wear this layer away. Only then will the tyres be able to exploit the full potential of grip from the new surface.

‘I’m not sure how good Barcelona is now for tyre testing, we will find out next week when the track has got rid of some of the shine,’ highlights Andy Green, Technical Director of Force India. ‘It’s quite a shock that the track has changed so much from a macro/micro perspective. It has a big effect on our tyres. For sure if we had known it was going to be this smooth we would have brought a whole different set of tyres to this test.’

This may seem rather obvious, but the bitumen is very black in colour and as we all know from wearing dark clothes in the sunshine, black absorbs heat quicker. So when the sun does come out, the track temperature will increase at a much quicker rate than in previous years. Although this is great news for tyre temperatures, this also has a negative effect as there will be a much larger temperature differential between the shady parts of the track and the areas in the sun. Depending on where the shadows are, this is something the drivers will have to continuously monitor because tyre temperatures could suddenly drop dramatically, and therefore the level of grip, which could prove entertaining into the braking zone of Turns 1 and 10 for example.

The other consequence of a smooth track, is the inability to absorb water, due to the close proximity of all the stones within the tarmac. Therefore, if it does rain, the track can become extremely slippery, extremely quickly.

Overall, grip will improve as the track evolves and only then will the track be consistent enough to complete representative tyre runs. Unfortunately, the current forecast of cold temperatures, rain and snow is not encouraging teams to go out. Furthermore, rain cleans the circuit, effectively removing all the rubber laid down from the previous day. Therefore, the second test next week will be the first time teams will get an idea on tyre performance.

Of course what everyone wants to know is the performance of the brand new pink coloured Hypersoft which is effectively two steps softer than last year’s Ultrasoft.

‘It’s pretty cold which isn’t going to be kind to the softer compounds, but the smoother track is definitely the right direction to work the Hypersoft,’ explains James Key, Technical Director of Toro Rosso. ‘We may get warmer conditions which will be OK to run the Hypersoft but we’ll have to see. This is really a track to test on because Sector 3 really hammers the tyres if you haven’t looked after them in Sector 1, so we’ll probably get a good impression of the Hypersoft later on.’

Similar to previous years, the first time teams will get a true representation of tyre performance will be in China due to the higher lateral and longitudinal loads. ‘Melbourne is always difficult because it’s not a track which is used all of the time,’ Green says. ‘When we get to the more traditional circuits we will have a better understanding of what changes Pirelli have made to the tyres.’