Lewis Hamilton will run a new turbo and MGU-H at the Spanish Grand Prix after Mercedes improved the design following reliability concerns.
MGU-H problems struck Hamilton in both China and Russia, causing him to start from the back of the grid in Shanghai and 10th in Sochi last time out. With Mercedes concerned by the recurrence of the problem it has worked on a new design which addresses reliability and therefore does not use any development tokens.
With Mercedes describing the work to prepare an updated turbo and MGU-H as "a superhuman effort", time constraints mean only Hamilton will have the new design in Barcelona this weekend as there is only one set available to the team.
Mercedes confirmed team-mate Nico Rosberg has a new internal combustion engine (ICE) and MGU-K "but retains the turbo and MGU-H that has run reliably so far this year". Rosberg currently holds a 43-point advantage over Hamilton in the drivers' championship having won each of the opening four races this season.
Rosberg and Hamilton were third and fourth fastest respectively in the first practice session for the Spanish Grand Prix, with Ferrari setting the pace but using the soft compound tyre in FP1.
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