diff --git a/src/dihedral_zero.cpp b/src/dihedral_zero.cpp
index 63ac52a224..ab4c12c226 100644
--- a/src/dihedral_zero.cpp
+++ b/src/dihedral_zero.cpp
@@ -27,7 +27,10 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-DihedralZero::DihedralZero(LAMMPS *lmp) : Dihedral(lmp), coeffflag(1) {}
+DihedralZero::DihedralZero(LAMMPS *lmp) : Dihedral(lmp), coeffflag(1)
+{
+  writedata = 1;
+}
 
 /* ---------------------------------------------------------------------- */
 
diff --git a/src/improper_zero.cpp b/src/improper_zero.cpp
index d9f36b8398..f177ff10d2 100644
--- a/src/improper_zero.cpp
+++ b/src/improper_zero.cpp
@@ -27,7 +27,10 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-ImproperZero::ImproperZero(LAMMPS *lmp) : Improper(lmp), coeffflag(1) {}
+ImproperZero::ImproperZero(LAMMPS *lmp) : Improper(lmp), coeffflag(1)
+{
+  writedata = 1;
+}
 
 /* ---------------------------------------------------------------------- */