Christian Horner admits Red Bull must make strides over the winter if they are to challenge Mercedes in 2015.
Though Daniel Ricciardo raced to three victories for Red Bull during the 2014 campaign, the Milton Keynes-based team were never able to fully challenge Mercedes’ dominance as the Silver Arrows swept to 18 poles, 16 wins and both the drivers’ and constructors’ titles via Formula1.com – Latest News http://ift.tt/13fNyBP