diff --git a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorFilterPanel.java b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorFilterPanel.java
index e23216b68..4ce03897d 100644
--- a/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorFilterPanel.java
+++ b/swing/src/net/sf/openrocket/gui/dialogs/motor/thrustcurve/MotorFilterPanel.java
@@ -298,7 +298,7 @@ public abstract class MotorFilterPanel extends JPanel {
 			// find the next largest diameter
 			int i;
 			for( i =0; i< diameterValues.length; i++ ) {
-				if ( mountDiameter< diameterValues[i] ) {
+				if ( mountDiameter< diameterValues[i] - 0.0005 ) {
 					break;
 				}
 			}