How to Turn Off or Change Mouse and Trackpad Acceleration in OS X Lion

Mouse and trackpad acceleration is very different on OS X than it is on Windows. While both operating systems have some degree of acceleration, OS X has a much larger rage of acceleration, which makes it a difficult adjustment for folks making the switch. Gamers especially pick up on this very quickly as it kills their “twitch” accuracy when spinning around and attempting to get the headshot on that enemy as they round the corner. Needless to say, it takes some getting used to.

Mouse acceleration is the gradual (or sudden) increase in cursor tracking speed as you move your mouse. It’s intended to allow you to drag the cursor across a larger space without having the move the mouse very far at all. Just move the mouse faster in a shorter space and the cursor zips across the screen at high speed. Slow down your movements and the cursor moves at a snail’s pace.

For this reason, it’s been my policy to disable or alter mouse acceleration on any Mac I own since OS X Snow Leopard. I’ve written about the process in the past, though some of the tricks I used to use to disable this “feature” have sadly been disabled as Apple has locked down certain terminal commands in the interest of security.

So, what can you do in OS X Lion and Mountain Lion if you need to turn mouse acceleration off? The answer is as easy as downloading an app from the Mac App Store.

Decelerate is an app available for use by anyone running OS X 10.6+ who wants to customize (or shut off) mouse acceleration on their Mac. It works great, and only needs to be set once.

There are a few things you have to keep in mind about it. Whenever you alter the acceleration settings, the mouse and trackpad settings will also change. You can lock in acceleration and go back into the mouse preference pane to boost tracking speed and reset your gestures. I had to restore right-click functionality on my Magic Mouse as well as tap clicks on the trackpad. It’s a bit of a hassle, but the end result is an acceleration level that doesn’t get you killed in FPS games.

The program has two selectable options and two sliders. You can disable Decelerate, save settings after you exit the app, and customize the level of acceleration on both your trackpad and mouse with two different sliders. This makes it easy for you to scale it down on your mouse and keep it springy on your trackpad.

Windows has a level of acceleration that sits around 0.5 on the mouse acceleration slider. If you want an experience that matches that of your Windows machine, this could be a great starting point. Turning off acceleration entirely is possible, though subconsciously you might actually miss that slight twinge of acceleration as you attempt to move across a large screen.

What about you? What is your trick for turning off mouse acceleration in OS X Lion or Mountain Lion?

Image: Decelerate