Issue making Bootstrap3 icon spin

The issue is that you rotate an element which is not centered in your span.

If you want a real solution, add transform-origin on .spin to change the center of rotation

.spin{
     -webkit-transform-origin: 50% 58%;
     transform-origin:50% 58%;
     -ms-transform-origin:50% 58%; /* IE 9 */
     -webkit-animation: spin .2s infinite linear;
     -moz-animation: spin .2s infinite linear;
     -o-animation: spin .2s infinite linear;
     animation: spin .2s infinite linear;
}

http://jsfiddle.net/L4zTu/5/