diff --git a/lib/timeline/TimeStep.js b/lib/timeline/TimeStep.js
index d4d5a8d3..8082961b 100644
--- a/lib/timeline/TimeStep.js
+++ b/lib/timeline/TimeStep.js
@@ -656,7 +656,7 @@ TimeStep.prototype.getClassName = function() {
       classNames.push(even(current.minutes()));
       break;
     case 'hour':
-      classNames.push('vis-h' + current.hours() + this.step == 4 ? '-h' + (current.hours() + 4) : '');
+      classNames.push('vis-h' + current.hours() + (this.step == 4 ? '-h' + (current.hours() + 4) : ''));
       classNames.push(today(current));
       classNames.push(even(current.hours()));
       break;