What is the fine-grained topic of the following text: Sometimes they where stripped down on completion because a key component was needed for another machine, for, say, the time trial machine- the carbon post allowed the saddle a few millimeters more forward adjustment, the cranks; I needed the long ones for more torque and they looked better with a single ring, but was the single a bad idea? Only return the topic.
Fine-tuning and modifying parts of a machine