diff --git a/gtsam/navigation/PreintegrationBase.cpp b/gtsam/navigation/PreintegrationBase.cpp
index c3c73e9d8..ed4ed583e 100644
--- a/gtsam/navigation/PreintegrationBase.cpp
+++ b/gtsam/navigation/PreintegrationBase.cpp
@@ -144,8 +144,9 @@ Vector9 PreintegrationBase::UpdateEstimate(const Vector3& a_body,
       velocity + a_nav* dt;                   // velocity
 
   if (A) {
-#define USE_NUMERICAL_DERIVATIVE
 #ifdef USE_NUMERICAL_DERIVATIVE
+    // The use of this yields much more accurate derivatives, but it's slow!
+    // TODO(frank): find a cheap closed form solution (look at Iserles)
     auto f = [w_body](const Vector3& theta) {
       return Rot3::ExpmapDerivative(theta).inverse() * w_body;
     };
@@ -153,7 +154,6 @@ Vector9 PreintegrationBase::UpdateEstimate(const Vector3& a_body,
         numericalDerivative11<Vector3, Vector3>(f, theta);
 #else
     // First order (small angle) approximation of derivative of invH*w:
-    // TODO(frank): find a cheap closed form solution (look at Iserles)
     // NOTE(frank): Rot3::ExpmapDerivative(w_body) is a less accurate approximation
     const Matrix3 invHw_H_theta = skewSymmetric(-0.5 * w_body);
 #endif
diff --git a/gtsam/navigation/tests/testCombinedImuFactor.cpp b/gtsam/navigation/tests/testCombinedImuFactor.cpp
index 06ceef994..036afcdb9 100644
--- a/gtsam/navigation/tests/testCombinedImuFactor.cpp
+++ b/gtsam/navigation/tests/testCombinedImuFactor.cpp
@@ -139,7 +139,7 @@ TEST(CombinedImuFactor, FirstOrderPreIntegratedMeasurements) {
   EXPECT(assert_equal(numericalDerivative21(zeta, Z_3x1, Z_3x1),
                       pim.zeta_H_biasAcc()));
   EXPECT(assert_equal(numericalDerivative22(zeta, Z_3x1, Z_3x1),
-                      pim.zeta_H_biasOmega(), 1e-7));
+                      pim.zeta_H_biasOmega(), 1e-3));
 }
 
 /* ************************************************************************* */
diff --git a/gtsam/navigation/tests/testImuFactor.cpp b/gtsam/navigation/tests/testImuFactor.cpp
index c02b49fbf..78e9c5ddd 100644
--- a/gtsam/navigation/tests/testImuFactor.cpp
+++ b/gtsam/navigation/tests/testImuFactor.cpp
@@ -453,7 +453,7 @@ TEST(ImuFactor, FirstOrderPreIntegratedMeasurements) {
   EXPECT(assert_equal(numericalDerivative21(zeta, Z_3x1, Z_3x1),
                       pim.zeta_H_biasAcc()));
   EXPECT(assert_equal(numericalDerivative22(zeta, Z_3x1, Z_3x1),
-                      pim.zeta_H_biasOmega(), 1e-7));
+                      pim.zeta_H_biasOmega(), 1e-3));
 }
 
 /* ************************************************************************* */