Bulk lubricant temperature under rig running conditions, mean temperature shown for each station for tests carried out at room temperature for UHMWPE-on-CoCr and UHMWPE-on-PEEK, data associated with 'Wear and Friction of UHMWPE-on-PEEK-OPTIMA' paper. 0% 2% 5% 25% 90% CoCr PEEK CoCr PEEK CoCr PEEK CoCr PEEK CoCr PEEK 24.8 26.2 26.1 27.5 25.8 27.2 25.2 26.9 24.1 25.1 25.5 27.0 27.0 28.8 26.7 26.9 25.9 26.2 24.9 26.0 26.4 26.9 27.7 28.8 27.6 28.6 27.0 27.7 25.6 26.2 31.0 30.9 28.5 27.9 25.9 26.0 28.0 27.6 26.3 26.9 31.9 31.5 29.0 28.6 27.0 26.9 27.4 28.0 27.3 27.4 31.5 31.9 28.4 28.6 26.7 27.9 28.8 27.6 27.9