diff --git a/src/modules/uxrce_dds_client/dds_topics.h.em b/src/modules/uxrce_dds_client/dds_topics.h.em
index dc79e0fabd..bcbc908d3a 100644
--- a/src/modules/uxrce_dds_client/dds_topics.h.em
+++ b/src/modules/uxrce_dds_client/dds_topics.h.em
@@ -105,7 +105,7 @@ static void on_topic_update(uxrSession *session, uxrObjectId object_id, uint16_t
 
 	switch (object_id.id) {
 @[    for idx, sub in enumerate(subscriptions)]@
-	case @(idx)+1000: {
+	case @(idx)+ (65535U / 32U) + 1: {
 			@(sub['simple_base_type'])_s data;
 
 			if (ucdr_deserialize_@(sub['simple_base_type'])(*ub, data, time_offset_us)) {
diff --git a/src/modules/uxrce_dds_client/utilities.hpp b/src/modules/uxrce_dds_client/utilities.hpp
index f20ae1d428..5c7fb2e9dc 100644
--- a/src/modules/uxrce_dds_client/utilities.hpp
+++ b/src/modules/uxrce_dds_client/utilities.hpp
@@ -10,17 +10,13 @@
 
 uxrObjectId topic_id_from_orb(ORB_ID orb_id, uint8_t instance = 0)
 {
-	// Note that the uxrObjectId.id is a uint16_t so we need to cap the ID.
-	// orb_id_size_t is currently uint16_t (MAX = 65535) and a max # of instances as either 4 or 10.
-	// We want to use half of the available id's for writers and half for readers,
-	// so this works as long as orb_id < 3276.
-	// Unfortunately, limits does not appear to be available. So hard-coding for uint16_t.
-	if (orb_id != ORB_ID::INVALID &&
-	    //(orb_id_size_t) orb_id < (std::numeric_limits<orb_id_size_t> / (2*ORB_MULTI_MAX_INSTANCES) )
-	    (orb_id_size_t) orb_id < (65535U / (2U * (uint16_t)ORB_MULTI_MAX_INSTANCES))
-	   ) {
-		uint16_t id = static_cast<orb_id_size_t>(orb_id) + (instance * ORB_TOPICS_COUNT);
-		uxrObjectId topic_id = uxr_object_id(id, UXR_TOPIC_ID);
+	// Note that the uxrObjectId.id is a uint16_t so we need to cap the ID,
+	// and urx does not allow us to use the upper 4 bits.
+	const unsigned max_id = 65535U / 32U;
+	const unsigned id = static_cast<unsigned>(orb_id) + (instance * ORB_TOPICS_COUNT);
+
+	if (orb_id != ORB_ID::INVALID && id < max_id) {
+		uxrObjectId topic_id = uxr_object_id(static_cast<uint16_t>(id), UXR_TOPIC_ID);
 		return topic_id;
 	}
 
@@ -103,8 +99,8 @@ static bool create_data_reader(uxrSession *session, uxrStreamId reliable_out_str
 	}
 
 	// Use the second half of the available ID space.
-	// Add 1 so that we get a nice hex starting number: 0x8000 instead of 0x7fff.
-	uint16_t id = index + (65535U / 2U) + 1;
+	// Add 1 so that we get a nice hex starting number: 0x800 instead of 0x7ff.
+	uint16_t id = index + (65535U / 32U) + 1;
 
 	uxrObjectId topic_id = uxr_object_id(id, UXR_TOPIC_ID);
 	uint16_t topic_req = uxr_buffer_create_topic_bin(session, reliable_out_stream_id, topic_id, participant_id, topic_name,