The teams are using
a new design of tyres
at the Nurburgring this weekend after six drivers suffered failures during the race at Silverstone.
Rosberg said he expected the tyres, which will use Kevlar rather than steel in their construction, would alter the relative competitiveness of the teams.
The revised tyres were run briefly in a damp practice session in Canada last month.
"It's early days," he said. "We ran them in Montreal but didn't learn much because of the weather.
British GP highlights: Nico Rosberg wins frenetic race
"We need to run them as much as possible in relevant circumstances but it will be interesting and it may shuffle things around a bit.
"It's very likely it will have an impact and it will be interesting. Possibly it will mix things up a bit and it's also an opportunity to understand it better and earlier."
"Hopefully the different tyre is safer for all of us, Silverstone was not we want or satisfactory. How much different or better the tyres will be is hard to judge.
"It's hard to know [whether it will favour one team over another]. Pirelli have to supply tyres and if you like it or not is up to you."
Vettel said Red Bull had sourced the problem that led to a broken fifth gear affecting his gearbox.
"We've understood and fixed the problem," he said.
German Grand Prix, day one
Friday 5 July: First practice at 08:55 on BBC Radio 5 live sports extra plus live text commentary online. Second practice at 12:55 BST on BBC Radio 5 live sports extra plus live text commentary online
German Grand Prix, day two
Saturday 6 July: Third practice at 09:55 BST on BBC Radio 5 live sports extra plus live text commentary online. Qualifying at 12:55 BST on BBC Radio 5 live sports extra plus live text commentary online. TV highlights of qualifying at 17:55 on BBC One
German Grand Prix, day three
Sunday 7 July: Race coverage at 12:30 BST on BBC Radio 5 live sports extra plus live text commentary online. TV highlights at 18:00 BST on BBC One
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