diff --git a/assets/themes/climbing/climbing.json b/assets/themes/climbing/climbing.json
index 0c733a5f08..5584ea44b6 100644
--- a/assets/themes/climbing/climbing.json
+++ b/assets/themes/climbing/climbing.json
@@ -99,8 +99,8 @@
           "_embedding_feature:access=feat.get('_embedding_features_with_access')?.access",
           "_embedding_feature:access:description=(feat.get('_embedding_features_with_access')??{})['access:description']",
           "_embedding_feature:id=feat.get('_embedding_features_with_access')?.id",
-          "__difficulty_max= feat.properties['climbing:grade:french:max'] ?? feat.properties['_difficulty_max']",
-          "__difficulty_min= feat.properties['climbing:grade:french:min'] ?? feat.properties['_difficulty_min']",
+          "__difficulty_max= (feat.properties['climbing:grade:french:max'] ?? feat.properties['_difficulty_max'])?.substring(0,2)?.toUpperCase()",
+          "__difficulty_min= (feat.properties['climbing:grade:french:min'] ?? feat.properties['_difficulty_min'])?.substring(0,2)?.toUpperCase()",
           "__difficulty_max:char= feat.properties['__difficulty_max']?.at(0)",
           "__difficulty_min:char= feat.properties['__difficulty_min']?.at(0)",
           "__difficulty:char= feat.properties['climbing:grade:french']?.at(0)",
@@ -309,4 +309,4 @@
     }
   ],
   "credits": "Christian Neumann <christian@utopicode.de>"
-}
\ No newline at end of file
+}