diff --git a/selfdrive/car/chrysler/interface.py b/selfdrive/car/chrysler/interface.py
index 34df32762d..eb40bc6f6e 100755
--- a/selfdrive/car/chrysler/interface.py
+++ b/selfdrive/car/chrysler/interface.py
@@ -58,9 +58,6 @@ class CarInterface(CarInterfaceBase):
 
     elif candidate == CAR.RAM_HD:
       ret.steerActuatorDelay = 0.2
-      ret.wheelbase = 3.785
-      ret.steerRatio = 15.61
-      ret.mass = 3405.
       CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning, 1.0, False)
 
     else:
diff --git a/selfdrive/car/chrysler/values.py b/selfdrive/car/chrysler/values.py
index a94512608a..1cc51753d4 100644
--- a/selfdrive/car/chrysler/values.py
+++ b/selfdrive/car/chrysler/values.py
@@ -19,12 +19,12 @@ class ChryslerCarInfo(CarInfo):
   car_parts: CarParts = field(default_factory=CarParts.common([CarHarness.fca]))
 
 
-@dataclass
+@dataclass(frozen=True)
 class ChryslerPlatformConfig(PlatformConfig):
   dbc_dict: DbcDict = field(default_factory=lambda: dbc_dict('chrysler_pacifica_2017_hybrid_generated', None))
 
 
-@dataclass
+@dataclass(frozen=True)
 class ChryslerCarSpecs(CarSpecs):
   minSteerSpeed: float = 3.8  # m/s