LE CASTELLET, France -- Valtteri Bottas is confident he has rediscovered his form at this weekend's French Grand Prix after beating teammate Lewis Hamilton in both Friday practice sessions.
Bottas was 0.008s off Max Verstappen's fastest time in second practice at Circuit Paul Ricard on Friday and 0.245s faster than Hamilton.
Closer analysis of the lap times showed Hamilton was losing most of his time on the straights, indicating he was simply running a lower power mode, but Bottas still appears to be more competitive than he was at the last round in Baku, where he finished a lowly 12th.
Hamilton was heard on team radio saying "something's not right with this car" during practice, but played down the comments when speaking to the media after the session.
Bottas' return to form and Hamilton's team radio comment coincide with news from Mercedes that it has swapped Hamilton's and Bottas' chassis for this weekend's race.
Bottas is now using chassis six, which Hamilton used for the first six races of the season, and Hamilton is using chassis four, which Bottas switched to after damaging chassis five at the Emilia Romagna Grand Prix in April.
Mercedes says the switch was made in order to manage mileage between the various chassis in its pool and was not related to the recent performances of the two cars.
Both chassis four and six were crack tested by the team ahead of the weekend and found to be in good condition. Chassis three remains available and could be built up if Hamilton believes there is an issue with chassis four.
"It's hard to say if it's the chassis or the track conditions, but there's a lot better feeling than two weeks ago, that's for sure," Bottas said after Friday practice.
"I felt we started the weekend on the right foot, everything was feeling OK, being comfortable and pretty fast with the car so far."
"It's such a different track, but the balance is good, the tyres are working well, I'm confident with the car, I can trust the car - I think that's the biggest difference."
Hamilton played down suggestions the chassis swap had impacted performance.
"It's a different track, so ... very rarely do you have any differences between the chassis."