As is becoming increasingly common, especially on carbon frames, internal routing is in place on the Thunderbolt - the rear derailleur housing and the line for the RockShox Reverb post run inside the downtube while the rear brake line is located outside the frame. A screw-on access plate is located on the downtube close to the BB92 bottom bracket to allow easy access to the internally routed housing, and it also makes the bike compatible with Shimano's Di2 electronic shifting system by creating a spot to mount the battery. For riders who are tired of schlepping around a hydration pack, or who want even more liquid carrying capacity, there's room for a full size water bottle to fit inside the front triangle, and another one can be carried on the underside of the downtube.