Combine Challenge 2018 UNBEATEN! We put the T-Series to the test right across Europe from the arid plains of central Spain to the steep slopes of Germany’s Harz mountains to the moist conditions of the Baltic and northern Europe. Delivering a minimum performance advantage of 20% over all its competitors the T-Series was in a class above. Thanks to all farmers and contractors who took part in the John Deere Combine Challenge 2018!