diff --git a/lib/src/darty.dart b/lib/src/darty.dart
index c6c9f62..158390e 100644
--- a/lib/src/darty.dart
+++ b/lib/src/darty.dart
@@ -107,7 +107,7 @@ class OptionBuilder {
 
   /// Disable the trailing slash which was added by default
   OptionBuilder disableAddTrailingSlash() {
-    _opts.remove('addTrailingSlash');
+    _opts['addTrailingSlash'] = false;
     return this;
   }