diff --git a/protocol/esta/rdm/message.cpp b/protocol/esta/rdm/message.cpp
index 99bb056..3d31830 100644
--- a/protocol/esta/rdm/message.cpp
+++ b/protocol/esta/rdm/message.cpp
@@ -170,10 +170,10 @@ void Message::write(std::vector<uint8_t> &buffer) const
       mdb.pid == DISC_UNIQUE_BRANCH.pid)
     return writeDiscBranch(buffer);
 
-  buffer.reserve(buffer.size() + 26 + mdb.pdl());    // pre-allocate necessary memory
+  buffer.reserve(buffer.size()+MESSAGE_MINIMUM_LENGTH+mdb.pdl()+2);    // pre-allocate necessary memory
   buffer.push_back(SC_RDM);
   buffer.push_back(SC_SUB_MESSAGE);
-  buffer.push_back(24 + mdb.pdl());
+  buffer.push_back(MESSAGE_MINIMUM_LENGTH+mdb.pdl());
   writeType(buffer, destination.manufacturer);
   writeType(buffer, destination.device);
   writeType(buffer, source.manufacturer);
@@ -205,7 +205,7 @@ void Message::writeDiscBranch(std::vector<uint8_t> &buffer) const
       mdb.pid != DISC_UNIQUE_BRANCH.pid)
     return write(buffer);
 
-  buffer.reserve(buffer.size() + 24);    // pre-allocate necessary memory
+  buffer.reserve(buffer.size() + MESSAGE_MINIMUM_LENGTH);    // pre-allocate necessary memory
 
   for (int i = 0; i < 7; i++)
     buffer.push_back(0xfe);     //!< Response Preamble bytes