diff --git a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/ImpulseClass.java b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/ImpulseClass.java
index 8f639c893..bb32530ea 100644
--- a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/ImpulseClass.java
+++ b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/ImpulseClass.java
@@ -3,7 +3,8 @@ package net.sf.openrocket.gui.dialogs.motor.thrustcurve;
 
 public enum ImpulseClass {
 
-	A("A",0.0, 2.5 ),
+// Impulse class A starts below zero to catch the MMX motors.
+	A("A",-1.0, 2.5 ),
 	B("B",2.5, 5.0 ),
 	C("C",5.0, 10.0),
 	D("D",10.0, 20.0),
diff --git a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorRowFilter.java b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorRowFilter.java
index b4ac85e9f..febe014b4 100644
--- a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorRowFilter.java
+++ b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorRowFilter.java
@@ -213,7 +213,7 @@ public class MotorRowFilter extends RowFilter<TableModel, Integer> implements Ch
 
 	private boolean filterByImpulseClass(ThrustCurveMotorSet m) {
 		if ( minimumImpulse != null ) {
-			if( m.getTotalImpuse() < minimumImpulse.getLow() ) {
+			if( m.getTotalImpuse() <= minimumImpulse.getLow() ) {
 				return false;
 			}
 		}