This is where the formula 1 class of mountain bike starts with the reaction from the stiff but light carbon frame to its high quality features and uncompromising spec the reaction gtc is amongst the very best high performance hardtails its equally at home blasting trails as it is racing endurance events in either 275 or 29 inch versions the reaction gtc twin mould frame offers everything youll need from a top notch carbon frame stiffness enhancing features like the large frame profile