Lewis Hamilton has offered a concerning assessment of Mercedes' pace after both Friday practice sessions for the Belgian Grand Prix.
Hamilton finished FP1 and FP2 ninth and sixth quickest respectively but admits that he struggled to pin-point where they lacked pace relative to Red Bull and Ferrari.
"We just weren't very quick, and I don't know why," Hamilton told media.
"It could be tyres, it could be tyre temps, it could be wing level, it could be a multitude of things.
"It doesn't feel disastrous out there. But we often find this on the Friday and then things change a little bit more on Saturday. I hope that that's the case."
Hamilton believes the car is like what he experienced during practice at the Hungaroring, when he managed to finish second in the race.
"It's doesn't feel the same as it did at the last track [Hungary] in qualifying, but more like Friday and Saturday morning, it feels kind of similar to that now, which gives me hope that we can turn it around," he said.
Mercedes use every dry tyre compound to find pace in practice
Along with setting times on the Medium and Soft tyres, Mercedes fitted the Hard rubber to both their cars in FP2 – although they still struggled with tyre temperatures, according to Hamilton's teammate, George Russell.
"We've struggled quite a lot this season to get the temperature into the tyres," he commented.
"I struggled quite a lot today with that on every compound we use, so in these conditions it's something we need to work on.
"But it's something I know you can find huge amount of performance from when you get it in the right windows, so there's a little bit of optimism there.
"But the gap to Max [Verstappen] and the Ferraris is pretty extravagant."
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Hamilton believes everyone at risk of taking engine penalties
Following the news that Verstappen and Leclerc will be taking power unit component penalties, Hamilton believes that everyone on the grid could be at risk at this stage of the season.
He added: "Everyone's [at] risk, but at the moment we're not taking any penalties. The team have done a great job with that.
"We've just got to work hard to analyse the data and try to figure out where we can get with this car."
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