diff --git a/speeduino/crankMaths.ino b/speeduino/crankMaths.ino
index c09c1261..00200400 100644
--- a/speeduino/crankMaths.ino
+++ b/speeduino/crankMaths.ino
@@ -41,9 +41,10 @@ unsigned long angleToTime(int16_t angle, byte method)
         {
           noInterrupts();
           unsigned long toothTime = (toothLastToothTime - toothLastMinusOneToothTime);
+          uint16_t tempTriggerToothAngle = triggerToothAngle; // triggerToothAngle is set by interrupts
           interrupts();
           
-          returnTime = ( (toothTime * angle) / triggerToothAngle );
+          returnTime = ( (toothTime * angle) / tempTriggerToothAngle );
         }
         else { returnTime = angleToTime(angle, CRANKMATH_METHOD_INTERVAL_REV); } //Safety check. This can occur if the last tooth seen was outside the normal pattern etc
     }
@@ -76,9 +77,10 @@ uint16_t timeToAngle(unsigned long time, byte method)
         {
           noInterrupts();
           unsigned long toothTime = (toothLastToothTime - toothLastMinusOneToothTime);
+          uint16_t tempTriggerToothAngle = triggerToothAngle; // triggerToothAngle is set by interrupts
           interrupts();
 
-          returnAngle = ( (unsigned long)(time * triggerToothAngle) / toothTime );
+          returnAngle = ( (unsigned long)(time * tempTriggerToothAngle) / toothTime );
         }
         else { returnAngle = timeToAngle(time, CRANKMATH_METHOD_INTERVAL_REV); } //Safety check. This can occur if the last tooth seen was outside the normal pattern etc
     }
diff --git a/speeduino/decoders.h b/speeduino/decoders.h
index c968b55b..8ce27001 100644
--- a/speeduino/decoders.h
+++ b/speeduino/decoders.h
@@ -233,7 +233,7 @@ extern volatile unsigned int secondaryToothCount; //Used for identifying the cur
 extern volatile unsigned long secondaryLastToothTime; //The time (micros()) that the last tooth was registered (Cam input)
 extern volatile unsigned long secondaryLastToothTime1; //The time (micros()) that the last tooth was registered (Cam input)
 
-extern volatile uint16_t triggerActualTeeth;
+extern uint16_t triggerActualTeeth;
 extern volatile unsigned long triggerFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering)
 extern volatile unsigned long triggerSecFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering) for the secondary input
 extern volatile bool validTrigger; //Is set true when the last trigger (Primary or secondary) was valid (ie passed filters)
diff --git a/speeduino/decoders.ino b/speeduino/decoders.ino
index c0d4bb6d..bf9c7569 100644
--- a/speeduino/decoders.ino
+++ b/speeduino/decoders.ino
@@ -76,7 +76,7 @@ volatile unsigned int secondaryToothCount; //Used for identifying the current se
 volatile unsigned long secondaryLastToothTime = 0; //The time (micros()) that the last tooth was registered (Cam input)
 volatile unsigned long secondaryLastToothTime1 = 0; //The time (micros()) that the last tooth was registered (Cam input)
 
-volatile uint16_t triggerActualTeeth;
+uint16_t triggerActualTeeth;
 volatile unsigned long triggerFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering)
 volatile unsigned long triggerSecFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering) for the secondary input
 volatile bool validTrigger; //Is set true when the last trigger (Primary or secondary) was valid (ie passed filters)