There are some things you can keep, but also some things you will have to change. I had the 08 t-bird and then changed to a zona zip. Ben is in fact wrong. The t-vee as external headset and the t-bird as an internal head set. Depending on what frame you want to upgrade to. You will/may have to change headset and pretty much the whole drivetrain system(cranks freewheel and possibly the BB). Depends what brake setup you have and changing to may depend on the brake mounts. The t-bird has a 19" rear wheel so you will not have to change that. I think I am correct on all of this. Maybe more you will have to change. EDIT: sorry ben i posted this then read your last post.