diff --git a/compact/definitions.xml b/compact/definitions.xml
index 4ec69ebb56a124bf8631555d7f9ec39101a1614c..ded1d622659cff0e879fec67f873ab1ac1938db0 100644
--- a/compact/definitions.xml
+++ b/compact/definitions.xml
@@ -3,5 +3,6 @@
     <constant name="Beampipe_rmax"   value="IPBeampipe_rmax"/>
     <constant name="BeampipeOD"      value="2.0*IPBeampipe_rmax"/>    
     <constant name="tracker_region_zmax"      value="2.0*mm"/>
+    <constant name="tracker_region_rmax"      value="2.0*mm"/>
   </define>