diff --git a/src/main/java/com/team766/hal/PIDSlotHelper.java b/src/main/java/com/team766/hal/PIDSlotHelper.java
index ec3d7b87f..adb953ee8 100644
--- a/src/main/java/com/team766/hal/PIDSlotHelper.java
+++ b/src/main/java/com/team766/hal/PIDSlotHelper.java
@@ -18,16 +18,16 @@ private Slot(int slot) {
             this.slot = slot;
             this.pGain =
                     new ObserveValue<Double>(
-                            ObserveValue.whenPresent((p) -> motor.setP(p, this.slot)));
+                            ObserveValue.whenPresent((p) -> motor.setP_Impl(p, this.slot)));
             this.iGain =
                     new ObserveValue<Double>(
-                            ObserveValue.whenPresent((i) -> motor.setI(i, this.slot)));
+                            ObserveValue.whenPresent((i) -> motor.setI_Impl(i, this.slot)));
             this.dGain =
                     new ObserveValue<Double>(
-                            ObserveValue.whenPresent((d) -> motor.setD(d, this.slot)));
+                            ObserveValue.whenPresent((d) -> motor.setD_Impl(d, this.slot)));
             this.ffGain =
                     new ObserveValue<Double>(
-                            ObserveValue.whenPresent((ff) -> motor.setFF(ff, this.slot)));
+                            ObserveValue.whenPresent((ff) -> motor.setFF_Impl(ff, this.slot)));
             this.outputMin =
                     new ObserveValue<Double>(ObserveValue.whenPresent((__) -> updateOutputRange()));
             this.outputMax =
@@ -35,17 +35,39 @@ private Slot(int slot) {
         }
 
         private void updateOutputRange() {
-            motor.setOutputRange(
+            motor.setOutputRange_Impl(
                     outputMin.getValueProvider().valueOr(-1.0),
                     outputMax.getValueProvider().valueOr(1.0),
                     slot);
         }
     }
 
-    private final MotorController motor;
+    /**
+     * The methods of this interface match the semantics of the similarly-named methods in
+     * {@link MotorController}, but it's important these set_Impl methods remain separate from the
+     * MotorController methods, otherwise PIDSlotHelper will not work properly.
+     * All of the MotorController methods should call PIDSlotHelper (rather than updating the motor
+     * device directly) otherwise PIDSlotHelper's ObserveValues will not be updated, and they will
+     * stay subscribed to the old ValueProvider.
+     */
+    public static interface MotorCallbacks {
+        int numPIDSlots();
+
+        void setP_Impl(double value, int slot);
+
+        void setI_Impl(double value, int slot);
+
+        void setD_Impl(double value, int slot);
+
+        void setFF_Impl(double value, int slot);
+
+        void setOutputRange_Impl(double minOutput, double maxOutput, int slot);
+    }
+
+    private final MotorCallbacks motor;
     private final Slot[] slots;
 
-    public PIDSlotHelper(MotorController motor) {
+    public PIDSlotHelper(MotorCallbacks motor) {
         this.motor = motor;
         final int size = motor.numPIDSlots();
         this.slots = new Slot[size];
diff --git a/src/main/java/com/team766/hal/wpilib/CANSparkMaxMotorController.java b/src/main/java/com/team766/hal/wpilib/CANSparkMaxMotorController.java
index 4a99e8089..0c2078c57 100644
--- a/src/main/java/com/team766/hal/wpilib/CANSparkMaxMotorController.java
+++ b/src/main/java/com/team766/hal/wpilib/CANSparkMaxMotorController.java
@@ -14,7 +14,8 @@
 import java.util.function.Function;
 import java.util.function.Supplier;
 
-public class CANSparkMaxMotorController extends CANSparkMax implements MotorController {
+public class CANSparkMaxMotorController extends CANSparkMax
+        implements MotorController, PIDSlotHelper.MotorCallbacks {
 
     private static final int NUM_PID_SLOTS = 2; // should be 4, only exposing 2 at this time.
 
@@ -155,7 +156,7 @@ public void setP(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setP(final double value, int slot) {
+    public void setP_Impl(final double value, int slot) {
         revErrorToException(ExceptionTarget.LOG, getPIDController().setP(value, slot));
     }
 
@@ -165,7 +166,7 @@ public void setI(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setI(final double value, int slot) {
+    public void setI_Impl(final double value, int slot) {
         revErrorToException(ExceptionTarget.LOG, getPIDController().setI(value, slot));
     }
 
@@ -175,7 +176,7 @@ public void setD(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setD(final double value, int slot) {
+    public void setD_Impl(final double value, int slot) {
         revErrorToException(ExceptionTarget.LOG, getPIDController().setD(value, slot));
     }
 
@@ -185,7 +186,7 @@ public void setFF(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setFF(final double value, int slot) {
+    public void setFF_Impl(final double value, int slot) {
         revErrorToException(ExceptionTarget.LOG, getPIDController().setFF(value, slot));
     }
 
@@ -282,7 +283,7 @@ public void setOutputRange(
     }
 
     @Override
-    public void setOutputRange(final double minOutput, final double maxOutput, int slot) {
+    public void setOutputRange_Impl(final double minOutput, final double maxOutput, int slot) {
         revErrorToException(
                 ExceptionTarget.LOG, getPIDController().setOutputRange(minOutput, maxOutput, slot));
     }
diff --git a/src/main/java/com/team766/hal/wpilib/CANTalonFxMotorController.java b/src/main/java/com/team766/hal/wpilib/CANTalonFxMotorController.java
index 06d2d8d10..5ac780cd6 100644
--- a/src/main/java/com/team766/hal/wpilib/CANTalonFxMotorController.java
+++ b/src/main/java/com/team766/hal/wpilib/CANTalonFxMotorController.java
@@ -27,7 +27,8 @@
 import com.team766.logging.LoggerExceptionUtils;
 import com.team766.logging.Severity;
 
-public class CANTalonFxMotorController extends TalonFX implements MotorController {
+public class CANTalonFxMotorController extends TalonFX
+        implements MotorController, PIDSlotHelper.MotorCallbacks {
 
     private static final int NUM_PID_SLOTS = 2;
 
@@ -194,7 +195,7 @@ public void setFF(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setFF(final double value, int slot) {
+    public void setFF_Impl(final double value, int slot) {
         refreshConfig();
         switch (slot) {
             case 0:
@@ -215,7 +216,7 @@ public void setP(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setP(final double value, int slot) {
+    public void setP_Impl(final double value, int slot) {
         refreshConfig();
         switch (slot) {
             case 0:
@@ -236,7 +237,7 @@ public void setI(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setI(final double value, int slot) {
+    public void setI_Impl(final double value, int slot) {
         refreshConfig();
         switch (slot) {
             case 0:
@@ -257,7 +258,7 @@ public void setD(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setD(final double value, int slot) {
+    public void setD_Impl(final double value, int slot) {
         refreshConfig();
         switch (slot) {
             case 0:
@@ -313,7 +314,7 @@ public void setOutputRange(
     }
 
     @Override
-    public void setOutputRange(final double minOutput, final double maxOutput, int slot) {
+    public void setOutputRange_Impl(final double minOutput, final double maxOutput, int slot) {
         if (slot != 0) {
             Logger.get(Category.HAL)
                     .logRaw(
diff --git a/src/main/java/com/team766/hal/wpilib/CANTalonMotorController.java b/src/main/java/com/team766/hal/wpilib/CANTalonMotorController.java
index 8c916680a..3072462c3 100644
--- a/src/main/java/com/team766/hal/wpilib/CANTalonMotorController.java
+++ b/src/main/java/com/team766/hal/wpilib/CANTalonMotorController.java
@@ -13,7 +13,8 @@
 import com.team766.logging.LoggerExceptionUtils;
 import com.team766.logging.Severity;
 
-public class CANTalonMotorController extends BaseCTREMotorController implements MotorController {
+public class CANTalonMotorController extends BaseCTREMotorController
+        implements MotorController, PIDSlotHelper.MotorCallbacks {
     private static final int NUM_PID_SLOTS = 2;
 
     private WPI_TalonSRX m_device;
@@ -139,22 +140,22 @@ public void setD(ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setFF(final double value, int slot) {
+    public void setFF_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kF(slot, value, TIMEOUT_MS));
     }
 
     @Override
-    public void setP(final double value, int slot) {
+    public void setP_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kP(slot, value));
     }
 
     @Override
-    public void setI(final double value, int slot) {
+    public void setI_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kI(slot, value));
     }
 
     @Override
-    public void setD(final double value, int slot) {
+    public void setD_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kD(slot, value));
     }
 
@@ -176,7 +177,7 @@ public void setOutputRange(
     }
 
     @Override
-    public void setOutputRange(final double minOutput, final double maxOutput, int slot) {
+    public void setOutputRange_Impl(final double minOutput, final double maxOutput, int slot) {
         if (slot != 0) {
             Logger.get(Category.HAL)
                     .logRaw(
diff --git a/src/main/java/com/team766/hal/wpilib/CANVictorMotorController.java b/src/main/java/com/team766/hal/wpilib/CANVictorMotorController.java
index 8292afb36..6b35b6643 100644
--- a/src/main/java/com/team766/hal/wpilib/CANVictorMotorController.java
+++ b/src/main/java/com/team766/hal/wpilib/CANVictorMotorController.java
@@ -13,7 +13,8 @@
 import com.team766.logging.LoggerExceptionUtils;
 import com.team766.logging.Severity;
 
-public class CANVictorMotorController extends BaseCTREMotorController implements MotorController {
+public class CANVictorMotorController extends BaseCTREMotorController
+        implements MotorController, PIDSlotHelper.MotorCallbacks {
     private static final int NUM_PID_SLOTS = 2;
 
     private final WPI_VictorSPX m_device;
@@ -121,7 +122,7 @@ public void setFF(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setFF(final double value, int slot) {
+    public void setFF_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kF(slot, value, TIMEOUT_MS));
     }
 
@@ -161,7 +162,7 @@ public void setP(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setP(final double value, int slot) {
+    public void setP_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kP(slot, value, TIMEOUT_MS));
     }
 
@@ -171,7 +172,7 @@ public void setI(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setI(final double value, int slot) {
+    public void setI_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kI(slot, value, TIMEOUT_MS));
     }
 
@@ -181,7 +182,7 @@ public void setD(final ValueProvider<Double> value, int slot) {
     }
 
     @Override
-    public void setD(final double value, int slot) {
+    public void setD_Impl(final double value, int slot) {
         errorCodeToException(ExceptionTarget.LOG, m_device.config_kD(slot, value, TIMEOUT_MS));
     }
 
@@ -203,7 +204,7 @@ public void setOutputRange(
     }
 
     @Override
-    public void setOutputRange(final double minOutput, final double maxOutput, int slot) {
+    public void setOutputRange_Impl(final double minOutput, final double maxOutput, int slot) {
         if (slot != 0) {
             Logger.get(Category.HAL)
                     .logRaw(