Tuned drivetrain.

Change-Id: I63b2d1ee22772dfde9317aacb0355506a4c3af00
diff --git a/bot3/control_loops/python/drivetrain.py b/bot3/control_loops/python/drivetrain.py
index c3144be..45c3387 100755
--- a/bot3/control_loops/python/drivetrain.py
+++ b/bot3/control_loops/python/drivetrain.py
@@ -63,7 +63,7 @@
     self.free_current = 2.7
     # Moment of inertia of the drivetrain in kg m^2
     # Just borrowed from last year.
-    self.J = 8
+    self.J = 10
     # Mass of the robot, in kg.
     self.m = 68
     # Radius of the robot, in meters (from last year).