diff --git a/src/sexp-simple-string.cpp b/src/sexp-simple-string.cpp
index fae1d4a..3029850 100644
--- a/src/sexp-simple-string.cpp
+++ b/src/sexp-simple-string.cpp
@@ -43,8 +43,9 @@ sexp_simple_string_t::sexp_simple_string_t(const octet_t *dt) : std::vector<octe
  * sexp_simple_string_t::sexp_simple_string_t(const octet_t *bt, size_t ln)
  */
 sexp_simple_string_t::sexp_simple_string_t(const octet_t *bt, size_t ln)
-    : std::vector<octet_t>(ln)
+    : std::vector<octet_t>()
 {
+    reserve(ln);
     for (size_t s = 0; s < ln; ++bt, ++s)
         push_back(*bt);
 }
diff --git a/tests/src/primitives-tests.cpp b/tests/src/primitives-tests.cpp
index 1813b73..c73a0b9 100644
--- a/tests/src/primitives-tests.cpp
+++ b/tests/src/primitives-tests.cpp
@@ -392,4 +392,15 @@ TEST_F(PrimitivesTests, EnsureHexTest)
     EXPECT_EQ(oss.str(), "(#610963#)");
 }
 
+TEST_F(PrimitivesTests, SimpleStringConstructors)
+{
+    const char* tss = "test simple string";
+
+    sexp_simple_string_t sss1 (reinterpret_cast<const octet_t *>(tss));
+    EXPECT_TRUE(sss1 == tss);
+
+    sexp_simple_string_t sss2 (reinterpret_cast<const octet_t *>(tss), 4);
+    EXPECT_TRUE(sss2 == "test");
+}
+
 } // namespace