diff --git a/lib/OpenLayers/Handler/MouseWheel.js b/lib/OpenLayers/Handler/MouseWheel.js
index 0228c0b74c..7cfc40cfce 100644
--- a/lib/OpenLayers/Handler/MouseWheel.js
+++ b/lib/OpenLayers/Handler/MouseWheel.js
@@ -176,7 +176,12 @@ OpenLayers.Handler.MouseWheel = OpenLayers.Class(OpenLayers.Handler, {
                     e = window.event;
                 }
                 if (e.wheelDelta) {
-                    delta = e.wheelDelta/this.analogWheelPrecision; 
+                    delta = e.wheelDelta;
+                    if (delta % 120 === 0) {
+                        delta = delta / 120;
+                    } else {
+                        delta = delta / this.analogWheelPrecision;
+                    }
                     if (window.opera && window.opera.version() < 9.2) {
                         delta = -delta;
                     }
diff --git a/tests/Handler/MouseWheel.html b/tests/Handler/MouseWheel.html
index 1d2a6b7eb5..d41c2cd18c 100644
--- a/tests/Handler/MouseWheel.html
+++ b/tests/Handler/MouseWheel.html
@@ -107,7 +107,7 @@
 
         var activated = handler.activate();
         
-        var delta = 360;
+        var delta = 120;
         if (window.opera && window.opera.version() < 9.2)  delta = -delta;
         handler.onWheelEvent({'target':map.layers[0].div, wheelDelta: delta});
         handler.onWheelEvent({'target':map.layers[0].div, wheelDelta: delta});