Although in 1979 Murray was the first to use lightweight carbon fibre composite panels to stiffen Brabham's aluminium alloy monocoques, he echoed his predecessor Tauranac in being the last to switch to the new fully composite monocoques. Murray was reluctant to build the entire chassis from composite materials until he understood their behaviour in a crash, an understanding achieved in part through an instrumented crash test of a BT49 chassis. The team did not follow McLaren's 1981 MP4/1 with their own fully composite chassis until the "lowline" BT55 in 1986, the last team to do so. This technology is now used in all top level single seater racing cars.