diff --git a/lib/OpenLayers/Layer/ArcGISCache.js b/lib/OpenLayers/Layer/ArcGISCache.js
index 228e90dbfb..b9671d35f4 100644
--- a/lib/OpenLayers/Layer/ArcGISCache.js
+++ b/lib/OpenLayers/Layer/ArcGISCache.js
@@ -459,7 +459,7 @@ OpenLayers.Layer.ArcGISCache = OpenLayers.Class(OpenLayers.Layer.XYZ, {
             // The tile images are stored using hex values on disk.
             x = 'C' + OpenLayers.Number.zeroPad(x, 8, 16);
             y = 'R' + OpenLayers.Number.zeroPad(y, 8, 16);
-            z = 'L' + OpenLayers.Number.zeroPad(z, 2, 16);
+            z = 'L' + OpenLayers.Number.zeroPad(z, 2, 10);
             url = url + '/${z}/${y}/${x}.' + this.type;
         }