diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index e7910548a9..32b04aca48 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -1713,7 +1713,7 @@ OpenLayers.Map = OpenLayers.Class({
      */
     adjustZoom: function(zoom) {
         var resolution, resolutions = this.baseLayer.resolutions,
-            maxResolution = this.getMaxExtent().getWidth() / this.getSize().w;
+            maxResolution = this.getMaxExtent().getWidth() / this.size.w;
         if (this.getResolutionForZoom(zoom) > maxResolution) {
             for (var i=zoom|0, ii=resolutions.length; i<ii; ++i) {
                 if (resolutions[i] <= maxResolution) {