diff --git a/extensions/yii/bootstrap/CHANGELOG.md b/extensions/yii/bootstrap/CHANGELOG.md
index 3dcc1f9..94b3d60 100644
--- a/extensions/yii/bootstrap/CHANGELOG.md
+++ b/extensions/yii/bootstrap/CHANGELOG.md
@@ -5,6 +5,7 @@ Yii Framework 2 bootstrap extension Change Log
 ----------------------------
 
 - Enh #1474: Added option to make NavBar 100% width (cebe)
+- Enh #1553: Only add navbar-default class to NavBar when no other class is specified (cebe)
 
 2.0.0 alpha, December 1, 2013
 -----------------------------
diff --git a/extensions/yii/bootstrap/NavBar.php b/extensions/yii/bootstrap/NavBar.php
index af76970..4a15481 100644
--- a/extensions/yii/bootstrap/NavBar.php
+++ b/extensions/yii/bootstrap/NavBar.php
@@ -67,7 +67,10 @@ class NavBar extends Widget
 	{
 		parent::init();
 		$this->clientOptions = false;
-		Html::addCssClass($this->options, 'navbar navbar-default');
+		Html::addCssClass($this->options, 'navbar');
+		if ($this->options['class'] == 'navbar') {
+			Html::addCssClass($this->options, 'navbar-default');
+		}
 		Html::addCssClass($this->brandOptions, 'navbar-brand');
 		if (empty($this->options['role'])) {
 			$this->options['role'] = 'navigation';