elantra 2021: steering ratio correction (#21686)

* actual steering ratio measurement

* steer ratio same for non-hybrid

selfdrive/car/hyundai/interface.py

@@ -73,7 +73,7 @@ class CarInterface(CarInterfaceBase):
       ret.lateralTuning.pid.kf = 0.00005
       ret.mass = (2800. * CV.LB_TO_KG) + STD_CARGO_KG
       ret.wheelbase = 2.72
-      ret.steerRatio = 13.27 * 1.15   # 15% higher at the center seems reasonable
+      ret.steerRatio = 12.9
       tire_stiffness_factor = 0.65
       ret.lateralTuning.pid.kiBP, ret.lateralTuning.pid.kpBP = [[0.], [0.]]
       ret.lateralTuning.pid.kpV, ret.lateralTuning.pid.kiV = [[0.25], [0.05]]
@@ -81,7 +81,7 @@ class CarInterface(CarInterfaceBase):
       ret.lateralTuning.pid.kf = 0.00005
       ret.mass = (3017. * CV.LB_TO_KG) + STD_CARGO_KG
       ret.wheelbase = 2.72
-      ret.steerRatio = 13.27 * 1.15   # 15% higher at the center seems reasonable
+      ret.steerRatio = 12.9
       tire_stiffness_factor = 0.65
       ret.lateralTuning.pid.kiBP, ret.lateralTuning.pid.kpBP = [[0.], [0.]]
       ret.lateralTuning.pid.kpV, ret.lateralTuning.pid.kiV = [[0.25], [0.05]]