diff --git a/frc971/control_loops/drivetrain/drivetrain_config.h b/frc971/control_loops/drivetrain/drivetrain_config.h
index c4652be..88547d5 100644
--- a/frc971/control_loops/drivetrain/drivetrain_config.h
+++ b/frc971/control_loops/drivetrain/drivetrain_config.h
@@ -72,6 +72,10 @@
   Scalar high_gear_ratio;
   Scalar low_gear_ratio;
 
+  // Moment of inertia and mass.
+  Scalar J;
+  Scalar mass;
+
   // Hall effect constants. Unused if not applicable to shifter type.
   constants::ShifterHallEffect left_drive;
   constants::ShifterHallEffect right_drive;
diff --git a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
index 49022f6..e4d320e 100644
--- a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
+++ b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
@@ -54,6 +54,8 @@
 
       ::y2016::control_loops::drivetrain::kHighGearRatio,
       ::y2016::control_loops::drivetrain::kLowGearRatio,
+      ::y2016::control_loops::drivetrain::kJ,
+      ::y2016::control_loops::drivetrain::kMass,
       kThreeStateDriveShifter,
       kThreeStateDriveShifter,
       false,
diff --git a/frc971/control_loops/drivetrain/trajectory_test.cc b/frc971/control_loops/drivetrain/trajectory_test.cc
index 58f0a22..89b5ffb 100644
--- a/frc971/control_loops/drivetrain/trajectory_test.cc
+++ b/frc971/control_loops/drivetrain/trajectory_test.cc
@@ -60,6 +60,8 @@
 
       ::y2016::control_loops::drivetrain::kHighGearRatio,
       ::y2016::control_loops::drivetrain::kLowGearRatio,
+      ::y2016::control_loops::drivetrain::kJ,
+      ::y2016::control_loops::drivetrain::kMass,
       kThreeStateDriveShifter,
       kThreeStateDriveShifter,
       false,
diff --git a/motors/simple_receiver.cc b/motors/simple_receiver.cc
index 91e2229..a78f1e0 100644
--- a/motors/simple_receiver.cc
+++ b/motors/simple_receiver.cc
@@ -76,7 +76,10 @@
       ::motors::seems_reasonable::kWheelRadius, ::motors::seems_reasonable::kV,
 
       ::motors::seems_reasonable::kHighGearRatio,
-      ::motors::seems_reasonable::kLowGearRatio, kThreeStateDriveShifter,
+      ::motors::seems_reasonable::kLowGearRatio,
+      ::motors::seems_reasonable::kJ,
+      ::motors::seems_reasonable::kMass,
+      kThreeStateDriveShifter,
       kThreeStateDriveShifter, true /* default_high_gear */,
       0 /* down_offset if using constants use
                                    constants::GetValues().down_error */, 0.8 /* wheel_non_linearity */,
diff --git a/y2012/control_loops/drivetrain/drivetrain_base.cc b/y2012/control_loops/drivetrain/drivetrain_base.cc
index 4e5a87f..40f4d24 100644
--- a/y2012/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2012/control_loops/drivetrain/drivetrain_base.cc
@@ -41,6 +41,8 @@
 
       drivetrain::kHighGearRatio,
       drivetrain::kLowGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter,
       kThreeStateDriveShifter,
       true /* default_high_gear */,
diff --git a/y2014/control_loops/drivetrain/drivetrain_base.cc b/y2014/control_loops/drivetrain/drivetrain_base.cc
index 8859f16..be4f238 100644
--- a/y2014/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2014/control_loops/drivetrain/drivetrain_base.cc
@@ -37,6 +37,8 @@
 
       constants::GetValues().high_gear_ratio,
       constants::GetValues().low_gear_ratio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       constants::GetValues().left_drive.shifter_hall_effect,
       constants::GetValues().right_drive.shifter_hall_effect,
       true /* default_high_gear */,
diff --git a/y2014_bot3/control_loops/drivetrain/drivetrain_base.cc b/y2014_bot3/control_loops/drivetrain/drivetrain_base.cc
index 4d03eca..89cda1a 100644
--- a/y2014_bot3/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2014_bot3/control_loops/drivetrain/drivetrain_base.cc
@@ -37,7 +37,8 @@
           chrono::duration<double>(drivetrain::kDt)),
       drivetrain::kRobotRadius, drivetrain::kWheelRadius, drivetrain::kV,
 
-      drivetrain::kHighGearRatio, drivetrain::kLowGearRatio,
+      drivetrain::kHighGearRatio, drivetrain::kLowGearRatio, drivetrain::kJ,
+      drivetrain::kMass,
 
       // No shifter sensors, so we could put anything for the things below.
       kThreeStateDriveShifter, kThreeStateDriveShifter,
diff --git a/y2016/control_loops/drivetrain/drivetrain_base.cc b/y2016/control_loops/drivetrain/drivetrain_base.cc
index 3a3f3c8..1be12ca 100644
--- a/y2016/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2016/control_loops/drivetrain/drivetrain_base.cc
@@ -42,6 +42,8 @@
 
       drivetrain::kHighGearRatio,
       drivetrain::kLowGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter,
       kThreeStateDriveShifter,
       true /* default_high_gear */,
diff --git a/y2017/control_loops/drivetrain/drivetrain_base.cc b/y2017/control_loops/drivetrain/drivetrain_base.cc
index 6cc7822..ea985d7 100644
--- a/y2017/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2017/control_loops/drivetrain/drivetrain_base.cc
@@ -42,6 +42,8 @@
 
       drivetrain::kHighGearRatio,
       drivetrain::kHighGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter,
       kThreeStateDriveShifter,
       true /* default_high_gear */,
diff --git a/y2017_bot3/control_loops/drivetrain/drivetrain_base.cc b/y2017_bot3/control_loops/drivetrain/drivetrain_base.cc
index 97b5ed4..da4aafb 100644
--- a/y2017_bot3/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2017_bot3/control_loops/drivetrain/drivetrain_base.cc
@@ -38,6 +38,8 @@
       drivetrain::kRobotRadius, drivetrain::kWheelRadius, drivetrain::kV,
 
       drivetrain::kHighGearRatio, drivetrain::kHighGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter, kThreeStateDriveShifter,
       // TODO(Neil): Find out whigh position is default in pneumatics for the
       // gearing
diff --git a/y2018/control_loops/drivetrain/drivetrain_base.cc b/y2018/control_loops/drivetrain/drivetrain_base.cc
index bfd1a48..cfb8a9a 100644
--- a/y2018/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2018/control_loops/drivetrain/drivetrain_base.cc
@@ -38,6 +38,8 @@
       drivetrain::kRobotRadius, drivetrain::kWheelRadius, drivetrain::kV,
 
       drivetrain::kHighGearRatio, drivetrain::kLowGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter, kThreeStateDriveShifter,
       true /* default_high_gear */, 0 /* down_offset if using constants use
                                    constants::GetValues().down_error */,
diff --git a/y2018_bot3/control_loops/drivetrain/drivetrain_base.cc b/y2018_bot3/control_loops/drivetrain/drivetrain_base.cc
index 4945947..23b0705 100644
--- a/y2018_bot3/control_loops/drivetrain/drivetrain_base.cc
+++ b/y2018_bot3/control_loops/drivetrain/drivetrain_base.cc
@@ -39,6 +39,8 @@
       drivetrain::kRobotRadius, drivetrain::kWheelRadius, drivetrain::kV,
 
       drivetrain::kHighGearRatio, drivetrain::kHighGearRatio,
+      drivetrain::kJ,
+      drivetrain::kMass,
       kThreeStateDriveShifter, kThreeStateDriveShifter,
       // TODO(sabina): confirm once robot is built
       true /* default_high_gear */, 0 /* down_offset */,