diff --git a/lib/OpenLayers/Layer/Grid.js b/lib/OpenLayers/Layer/Grid.js
index 79bb0abfc4..13b55977ba 100644
--- a/lib/OpenLayers/Layer/Grid.js
+++ b/lib/OpenLayers/Layer/Grid.js
@@ -1,6 +1,8 @@
 // @require: OpenLayers/Layer.js
 // @require: OpenLayers/Util.js
 OpenLayers.Layer.Grid = Class.create();
+OpenLayers.Layer.Grid.TILE_WIDTH = 256;
+OpenLayers.Layer.Grid.TILE_HEIGHT = 256;
 OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
     
     // str: url
@@ -10,8 +12,8 @@ OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
     params: null,
 
     // tileSize: OpenLayers.Size
-    tileSize: new OpenLayers.Size(256,256),
-
+    tileSize: null,
+    
     // grid: Array(Array())
     // this is an array of rows, each row is an array of tiles
     grid: null,
@@ -29,6 +31,8 @@ OpenLayers.Layer.Grid.prototype = Object.extend( new OpenLayers.Layer(), {
         OpenLayers.Layer.prototype.initialize.apply(this, newArguments);
         this.url = url;
         this.params = params;
+        this.tileSize = new OpenLayers.Size(OpenLayers.Layer.Grid.TILE_WIDTH,
+                                            OpenLayers.Layer.Grid.TILE_HEIGHT);
     },
 
     setTileSize: function (size) {