( CNN ) -- Seven-time world champion Michael Schumacher has continued to pillory Pirelli 's tires , complaining that they are like driving on `` raw eggs . '' The Mercedes driver blamed the quicker degradation of the Italian manufacturer 's products for the scenario which has seen four race winners in as many starts this season , and much closer competition between the drivers . `` I just think that they 're playing a much too big effect because they are so peaky and so special that they do n't put our cars or ourselves to the limit , '' he told CNN ahead of this weekend 's Spanish Grand Prix . `` We drive like on raw eggs and I do n't want to stress the tires at all . Otherwise you just overdo it and you go nowhere . '' The 43-year-old German has been a vocal critic of Pirelli , calling on the company to rethink its approach after several drivers struggled with tire degradation during last month 's Bahrain Grand Prix . He was backed by McLaren team boss Martin Whitmarsh , whose drivers also struggled with the tires . Jenson Button suffered a puncture with three laps remaining , retiring on the penultimate lap , while Lewis Hamilton finished down in eighth and lost his championship lead to race winner Sebastian Vettel . Pirelli replaced Bridgestone as F1 's sole tire supplier in 2011 , winning a three-year contract . Bridgestone had been the sole provider from 2007-2010 , after Michelin pulled out . However , Pirelli has argued it should be congratulated for such an open , unpredictable season . The manufacturer claimed it was simply responding to calls for more eventful racing , with director Paul Hembery saying : `` We are pushing the limits . `` It 's a very , very aggressive approach that we took . It 's what we were asked to do . We were asked to bring challenges to the teams and this is what we 've done . '' Schumacher 's teammate Nico Rosberg , however , had a very different view on the tires . The 26-year-old German , who won the Chinese Grand Prix last month for his first victory in 111 attempts , took a positive spin on the unpredictability . `` I find it a big challenge for us drivers and an interesting challenge . It 's different but very interesting , '' he told CNN . `` This tire management , getting the most out of it , understanding when to push , when to take it easy . It 's so on a knife 's edge with the tires that it 's good and it 's great for racing . It 's great , it 's mixed everything up , lots of overtaking , lots of things happening , fantastic for everybody . '' While Rosberg is sixth in the drivers ' rankings , Schumacher is languishing in 18th as he seeks his first podium placing since coming out of retirement in 2010 . However , the former Ferrari star is proud to see younger compatriots such as Rosberg , Nico Hulkenberg of Force India and Marussia 's Timo Glock with him on the 24-strong grid this season , and he reserved special praise for Red Bull 's double world champion Vettel . `` Being good friends , particularly with Sebastian , sort of makes it even more special because he grew up on my go-kart track , '' Schumacher said . `` We know each other from childhood . His childhood mainly -- I was a little bit grown up by that stage . And seeing him do well makes me proud . '' The Mercedes cars have been a lot more competitive this season , and Schumacher hopes they can transform their improved pace with more consistent race results . `` We have got one win under our belt . Got a bit unlucky in that race -- could have been a one-two without a doubt -- but it proves that we made a huge step because we have to consider where we come from , '' he said . `` Last year was n't really what we were looking for . Starting the Silver Arrow new generation we had media success and finally we managed a victory , and I 'm pretty sure we can have other good races this year being on the podium , and maybe even being on top of the podium . ''
Michael Schumacher criticizes Pirelli 's tires , complaining they degrade too quickly . Seven-time world champ says tires are stopping drivers from pushing themselves . Sole supplier Pirelli says tires have produced an exciting , unpredictable season . Comment: