Nico Rosberg lost his shot at winning the British GP to a mechanical gearbox problem that left him stranded at trackside on the 29th lap.
Rosberg was just ahead of Lewis Hamilton at the time, and it was not yet clear how their respective strategies would play out. It was his first retirement of the year after he had finished first or second in the eight previous races, and it leaves him just four points clear of Hamilton.
Rosberg said he’d seen signs of an issue earlier in the race.
“There was one thing already before the start,” he said, “Or just after or something like that, which was weird. And then after that it sort of got worse and worse from lap 20 onwards. There were some occasions where I had neutral so I had to pull the clutch and go again, and then it just got worse and worse.
“My mentality changed to, ‘OK, let’s stop racing Lewis, and let’s just try and get this thing to the end somehow,’ because I have such a pace advantage, and I know that I can do some pretty radical things to try and keep this gearbox alive. But it was a mechanical problem, and there wasn’t anything that could be done.”
Rosberg said he would try find some positives: “What can I say, it was just a reliability problem, and a pity. So now we need to review it, and as always we need to push on and try and keep on working on any small reliability issues that we’re having, as we have done, and as we’re still doing.
“It’s difficult to find so many good feelings today, but tomorrow we’ll try to look for them again. I’m in the lead of the championship.”
Adam Cooper's F1 Blog 
What kind of pace advantage did Nico have over Lewis, who was faster than him on the hards, while Rosberg was on the mediums. Nico needs to rethink such a response.
By the time Lewis put the hard tyres on Nico was having issues. That’s why on brand new medium tyres he was only marginally faster than Lewis, when normally you’d be far quicker.
The commentators on Sky didn’t know the arse from their elbow, it was evident that it wasn’t the new tyres that were aiding Hamilton in catching Rosberg so quickly, it was the gearbox issue that Nico had.
If the hard tyres were so much quicker all the other teams would have switched on to them, They didn’t.
If you look at the lap times you’ll see that Rosbergs pace was very consistent and it took Lewis the best part of 15 laps to pull in 3 seconds. Then Rosberg starts to get some minor issues, and Hamilton gains something like 1.2s in two laps. Nico pits. Rosberg on fresh rubber, but a slight car issue is able to go a little faster (new rubber masking the issue from a timing screen perspective). Lewis pits, new tyres on and then you get to see new tyres + good car vs new tyres and a dodgy gearbox.
Shame really, once Nico retired the race was over, as nothing other than a Merc can win unless they have car issues.
Not over Lewis, but over the rest of the field. He says he stopped trying to beat Lewis, but instead just to bring the car home to score some points.