diff --git a/core/src/main/java/info/openrocket/core/material/MaterialGroup.java b/core/src/main/java/info/openrocket/core/material/MaterialGroup.java
index 9bbbc4784..673df1591 100644
--- a/core/src/main/java/info/openrocket/core/material/MaterialGroup.java
+++ b/core/src/main/java/info/openrocket/core/material/MaterialGroup.java
@@ -18,7 +18,7 @@ public class MaterialGroup implements Comparable<MaterialGroup>, Group {
 	public static final MaterialGroup PAPER = new MaterialGroup(trans.get("MaterialGroup.PaperProducts"), "PaperProducts", 40, false);
 	public static final MaterialGroup FOAMS = new MaterialGroup(trans.get("MaterialGroup.Foams"), "Foams", 50, false);
 	public static final MaterialGroup COMPOSITES = new MaterialGroup(trans.get("MaterialGroup.Composites"), "Composites", 60, false);
-	public static final MaterialGroup FIBERS = new MaterialGroup(trans.get("MaterialGroup.Fibers"), "Fibres", 70, false);
+	public static final MaterialGroup FIBERS = new MaterialGroup(trans.get("MaterialGroup.Fibers"), "Fibers", 70, false);
 	public static final MaterialGroup THREADS_LINES = new MaterialGroup(trans.get("MaterialGroup.ThreadsLines"), "ThreadsLines", 80, false);
 	public static final MaterialGroup OTHER = new MaterialGroup(trans.get("MaterialGroup.Other"), "Other", 90, false);
 
diff --git a/core/src/main/java/info/openrocket/core/preset/xml/MaterialGroupDTO.java b/core/src/main/java/info/openrocket/core/preset/xml/MaterialGroupDTO.java
index 5be788499..bb287fed4 100644
--- a/core/src/main/java/info/openrocket/core/preset/xml/MaterialGroupDTO.java
+++ b/core/src/main/java/info/openrocket/core/preset/xml/MaterialGroupDTO.java
@@ -24,7 +24,7 @@ public enum MaterialGroupDTO {
 	FOAMS(MaterialGroup.FOAMS),
 	@XmlEnumValue("Composites")
 	COMPOSITES(MaterialGroup.COMPOSITES),
-	@XmlEnumValue("Fibres")
+	@XmlEnumValue("Fibers")
 	FIBERS(MaterialGroup.FIBERS),
 	@XmlEnumValue("ThreadsLines")
 	THREADS_LINES(MaterialGroup.THREADS_LINES),