diff --git a/core/src/net/sf/openrocket/rocketcomponent/ComponentAssembly.java b/core/src/net/sf/openrocket/rocketcomponent/ComponentAssembly.java
index 16c40b0ac..75d688849 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/ComponentAssembly.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/ComponentAssembly.java
@@ -87,8 +87,8 @@ public abstract class ComponentAssembly extends RocketComponent implements  Axia
 	public double getRotationalUnitInertia() {
 		return 0;
 	}
-	
-	public double getOuterRadius(){
+
+	public double getBoundingRadius(){
 		double outerRadius=0;
 		for( RocketComponent comp : children ){
 			double thisRadius=0;
diff --git a/core/src/net/sf/openrocket/rocketcomponent/FinSet.java b/core/src/net/sf/openrocket/rocketcomponent/FinSet.java
index b508766db..d5387aebf 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/FinSet.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/FinSet.java
@@ -455,10 +455,10 @@ public abstract class FinSet extends ExternalComponent implements RingInstanceab
 	}
 	
 	@Override
-	public double getOuterRadius(){
-		return 0.0;
+	public double getBoundingRadius(){
+		return 0.;
 	}
-	
+
 	private void calculateAreaCG() {
 		Coordinate[] points = this.getFinPoints();
 		finArea = 0;
diff --git a/core/src/net/sf/openrocket/rocketcomponent/position/RadiusMethod.java b/core/src/net/sf/openrocket/rocketcomponent/position/RadiusMethod.java
index eccba4d08..b671953c6 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/position/RadiusMethod.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/position/RadiusMethod.java
@@ -34,10 +34,14 @@ public enum RadiusMethod implements DistanceMethod {
 		
 		@Override
 		public double getRadius( final RocketComponent parentComponent, final RocketComponent thisComponent, final double requestedOffset ){
-			if( (parentComponent instanceof BodyTube ) && (thisComponent instanceof RadiusPositionable ) ) {
-				return (((BodyTube)parentComponent).getOuterRadius()+((RadiusPositionable)thisComponent).getOuterRadius() + requestedOffset);
+			double radius = requestedOffset;
+			if( parentComponent instanceof BodyTube ) {
+				radius += ((BodyTube)parentComponent).getOuterRadius();
 			}
-			return requestedOffset; // fail-safe path
+			if( thisComponent instanceof RadiusPositionable ) {
+				radius += ((RadiusPositionable)thisComponent).getBoundingRadius();
+			}
+			return radius;
 		}
 	},
 
@@ -47,10 +51,14 @@ public enum RadiusMethod implements DistanceMethod {
 	SURFACE ( Application.getTranslator().get("RocketComponent.Position.Method.Radius.SURFACE") ) {
 		@Override
 		public double getRadius( final RocketComponent parentComponent, final RocketComponent thisComponent, final double requestedOffset ){
-			if( (parentComponent instanceof BodyTube ) && (thisComponent instanceof RadiusPositionable ) ) {
-				return ((BodyTube)parentComponent).getOuterRadius()+((RadiusPositionable)thisComponent).getOuterRadius();
+			double radius = 0.;
+			if( parentComponent instanceof BodyTube ) {
+				radius += ((BodyTube)parentComponent).getOuterRadius();
 			}
-			return 0.; // fail-safe path
+			if( thisComponent instanceof RadiusPositionable ) {
+				radius += ((RadiusPositionable)thisComponent).getBoundingRadius();
+			}
+			return radius;
 		}
 	};
 
@@ -70,7 +78,7 @@ public enum RadiusMethod implements DistanceMethod {
 	public String toString() {
 		return description;
 	}
-	
+
 	@Override
 	public boolean clampToZero() { return true; }
 	
diff --git a/core/src/net/sf/openrocket/rocketcomponent/position/RadiusPositionable.java b/core/src/net/sf/openrocket/rocketcomponent/position/RadiusPositionable.java
index d730a704d..68c749783 100644
--- a/core/src/net/sf/openrocket/rocketcomponent/position/RadiusPositionable.java
+++ b/core/src/net/sf/openrocket/rocketcomponent/position/RadiusPositionable.java
@@ -1,9 +1,9 @@
 package net.sf.openrocket.rocketcomponent.position;
 
 public interface RadiusPositionable {
-	
-	public double getOuterRadius();
-	
+
+    public double getBoundingRadius();
+
 	public double getRadiusOffset();
 	public void setRadiusOffset(final double radius);