diff --git a/selfdrive/car/gm/interface.py b/selfdrive/car/gm/interface.py
index 1afa5c7d7..f7dbb40f5 100644
--- a/selfdrive/car/gm/interface.py
+++ b/selfdrive/car/gm/interface.py
@@ -254,8 +254,8 @@ class CarInterface(CarInterfaceBase):
       ret.lateralTuning.torque.ki = 1.07  # torque_ff_scale_neg
       ret.lateralTuning.torque.kd = 0.93  # torque_ki_mult
       ret.lateralTuning.torque.kfDEPRECATED = 0.02  # torque_deadzone_boost_neg (lat accel)
-      ret.lateralTuning.torque.latAccelFactor = 0.78
-      ret.lateralTuning.torque.friction = 0.155
+      # Silverado-only: reduce base friction for left bias 
+      ret.lateralTuning.torque.friction *= 0.93
 
     elif candidate in (CAR.CHEVROLET_EQUINOX, CAR.CHEVROLET_EQUINOX_CC):
       CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning)
diff --git a/selfdrive/car/gm/values.py b/selfdrive/car/gm/values.py
index e1ec173f8..eaac4d135 100644
--- a/selfdrive/car/gm/values.py
+++ b/selfdrive/car/gm/values.py
@@ -175,7 +175,7 @@ class CAR(Platforms):
       GMCarDocs("Chevrolet Silverado 1500 2020-21", "Safety Package II"),
       GMCarDocs("GMC Sierra 1500 2020-21", "Driver Alert Package II", video_link="https://youtu.be/5HbNoBLzRwE"),
     ],
-    GMCarSpecs(mass=2994, wheelbase=3.75, steerRatio=17.35, tireStiffnessFactor=1.0),
+    GMCarSpecs(mass=2994, wheelbase=3.75, steerRatio=16.3, tireStiffnessFactor=1.0),
   )
   CHEVROLET_EQUINOX = GMPlatformConfig(
     [GMCarDocs("Chevrolet Equinox 2019-22")],