diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Backend.h b/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
index f8b47d482d..77fff6a3ea 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Backend.h
@@ -22,7 +22,7 @@ class AP_WheelEncoder_Backend
 {
 public:
     // constructor. This incorporates initialisation as well.
-	AP_WheelEncoder_Backend(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state);
+    AP_WheelEncoder_Backend(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state);
 
     // we declare a virtual destructor so that WheelEncoder drivers can
     // override with a custom destructor if need be
diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
index 4b03289fc1..45928caa4d 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
@@ -23,7 +23,7 @@ extern const AP_HAL::HAL& hal;
 
 // constructor
 AP_WheelEncoder_Quadrature::AP_WheelEncoder_Quadrature(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state) :
-	AP_WheelEncoder_Backend(frontend, instance, state)
+    AP_WheelEncoder_Backend(frontend, instance, state)
 {
 }