Originally Posted by sphynx_000
what do you mean push to release, same as push-push?
release tension, and switch a gear?
Yes. Push to release means you push on a button/lever in order to release the cable tension. Older first generation RapidFire shifters had a release button positioned over the pull-lever. You pushed on the cable-pull lever to pull the cable and you pushed the button to release the tension. Shimano then switched to using a trigger which you pulled to released the tension. The latest generation of RapidFires allow you to do either. You can push or pull on the release lever. And it has a double-throw meaning you can push or pull further to release enough cable to shift up to two cogs at a time.