diff --git a/src/main.cpp b/src/main.cpp
index e0cab45..fde9eb2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -185,7 +185,7 @@ void compte_tour() {
     chrono_compte_tour = millis()- start_chrono_scribe;
     pcnt_get_counter_value(PCNT_UNIT_0, &count);
     int diff_count = count - old_count;
-    vRotReel = (60000*diff_count/(pptr*chrono_compte_tour)); //vitesse en tours par min (4 pulsations /tour, 2 montantes, 2 descendantes)
+    vRotReel = (60000*diff_count/(pptr*offset)); //vitesse en tours par min (4 pulsations /tour, 2 montantes, 2 descendantes)
     old_count = count;
     Serial.println("count =");
     Serial.println(count);