diff --git a/actionpack/lib/action_controller/routing/recognition_optimisation.rb b/actionpack/lib/action_controller/routing/recognition_optimisation.rb
index 6d54d0334c..306219a431 100644
--- a/actionpack/lib/action_controller/routing/recognition_optimisation.rb
+++ b/actionpack/lib/action_controller/routing/recognition_optimisation.rb
@@ -147,6 +147,15 @@ module ActionController
             end
           }, __FILE__, __LINE__
         end
+
+        def clear_recognize_optimized!
+          instance_eval %{
+            def recognize_optimized(path, environment)
+              write_recognize_optimized!
+              recognize_optimized(path, environment)
+            end
+          }, __FILE__, __LINE__
+        end
     end
   end
 end
diff --git a/actionpack/lib/action_controller/routing/route_set.rb b/actionpack/lib/action_controller/routing/route_set.rb
index 9d48f289db..ff448490e9 100644
--- a/actionpack/lib/action_controller/routing/route_set.rb
+++ b/actionpack/lib/action_controller/routing/route_set.rb
@@ -195,7 +195,7 @@ module ActionController
         self.routes = []
         self.named_routes = NamedRouteCollection.new
 
-        write_recognize_optimized!
+        clear_recognize_optimized!
       end
 
       # Subclasses and plugins may override this method to specify a different
@@ -217,7 +217,7 @@ module ActionController
         @routes_by_controller = nil
         # This will force routing/recognition_optimization.rb
         # to refresh optimisations.
-        @compiled_recognize_optimized = nil
+        clear_recognize_optimized!
       end
 
       def install_helpers(destinations = [ActionController::Base, ActionView::Base], regenerate_code = false)
diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
index 8bb1c49cbd..1eb26a7cfd 100644
--- a/actionpack/test/controller/routing_test.rb
+++ b/actionpack/test/controller/routing_test.rb
@@ -1375,6 +1375,36 @@ uses_mocha 'LegacyRouteSet, Route, RouteSet and RouteLoading' do
         x.send(:foo_with_requirement_url, "I am Against the requirements")
       end
     end
+
+    def test_routes_changed_correctly_after_clear
+      ActionController::Base.optimise_named_routes = true
+      rs = ::ActionController::Routing::RouteSet.new
+      rs.draw do |r|
+        r.connect 'ca', :controller => 'ca', :action => "aa"
+        r.connect 'cb', :controller => 'cb', :action => "ab"
+        r.connect 'cc', :controller => 'cc', :action => "ac"
+        r.connect ':controller/:action/:id'
+        r.connect ':controller/:action/:id.:format'
+      end
+
+      hash = rs.recognize_path "/cc"
+
+      assert_not_nil hash
+      assert_equal %w(cc ac), [hash[:controller], hash[:action]]
+
+      rs.draw do |r|
+        r.connect 'cb', :controller => 'cb', :action => "ab"
+        r.connect 'cc', :controller => 'cc', :action => "ac"
+        r.connect ':controller/:action/:id'
+        r.connect ':controller/:action/:id.:format'
+      end
+
+      hash = rs.recognize_path "/cc"
+
+      assert_not_nil hash
+      assert_equal %w(cc ac), [hash[:controller], hash[:action]]
+
+    end
   end
 
   class RouteTest < Test::Unit::TestCase