diff --git a/src/core/include/units/magnitude.h b/src/core/include/units/magnitude.h
index fbe93316..5f01a0fa 100644
--- a/src/core/include/units/magnitude.h
+++ b/src/core/include/units/magnitude.h
@@ -33,7 +33,7 @@ namespace units {
 namespace detail
 {
 // Higher numbers use fewer trial divisions, at the price of more storage space.
-using Factorizer = WheelFactorizer<6>;
+using Factorizer = WheelFactorizer<4>;
 } // namespace detail
 
 /**
diff --git a/test/unit_test/static/prime_test.cpp b/test/unit_test/static/prime_test.cpp
index cfb57273..ab852974 100644
--- a/test/unit_test/static/prime_test.cpp
+++ b/test/unit_test/static/prime_test.cpp
@@ -50,7 +50,6 @@ static_assert(WheelFactorizer<2>::coprimes_in_first_wheel.size() == 2);
 static_assert(WheelFactorizer<3>::coprimes_in_first_wheel.size() == 8);
 static_assert(WheelFactorizer<4>::coprimes_in_first_wheel.size() == 48);
 static_assert(WheelFactorizer<5>::coprimes_in_first_wheel.size() == 480);
-static_assert(WheelFactorizer<6>::coprimes_in_first_wheel.size() == 5760);
 
 static_assert(WheelFactorizer<3>::coprimes_in_first_wheel[0] == 1);
 static_assert(WheelFactorizer<3>::coprimes_in_first_wheel[1] == 7);