diff --git a/routes/threecx.py b/routes/threecx.py
index ab5af21..66b4b28 100644
--- a/routes/threecx.py
+++ b/routes/threecx.py
@@ -35,7 +35,7 @@ def handle_threecx_outbound():
         text = json_data.get("text", "")
         media_urls = json_data.get("media_urls", [])
 
-        is_mms = bool(media_urls) or len(text) > 160
+        is_mms = bool(media_urls) or len(text) > 158
 
         if is_mms and not media_urls:
             json_data["media_urls"] = [""]