diff --git a/metricflow/time/time_granularity_solver.py b/metricflow/time/time_granularity_solver.py
index 1cbfcff8c4..528edce977 100644
--- a/metricflow/time/time_granularity_solver.py
+++ b/metricflow/time/time_granularity_solver.py
@@ -71,7 +71,9 @@ def __init__(  # noqa: D
         read_nodes: Sequence[ReadSqlSourceNode],
     ) -> None:
         self._semantic_manifest_lookup = semantic_manifest_lookup
-        self._time_dimension_names_to_supported_granularities: Dict[str, Set[TimeGranularity]] = defaultdict(set)
+        self._time_dimensions_to_supported_granularities: Dict[
+            TimeDimensionReference, Set[TimeGranularity]
+        ] = defaultdict(set)
         for read_node in read_nodes:
             output_data_set = node_output_resolver.get_output_data_set(read_node)
             for time_dimension_instance in output_data_set.instance_set.time_dimension_instances:
@@ -80,10 +82,10 @@ def __init__(  # noqa: D
                 granularity_free_qualified_name = StructuredLinkableSpecName.from_name(
                     time_dimension_instance.spec.qualified_name
                 ).granularity_free_qualified_name
-                self._time_dimension_names_to_supported_granularities[granularity_free_qualified_name].add(
-                    time_dimension_instance.spec.time_granularity
-                )
-        self._time_dimension_names_to_supported_granularities[DataSet.metric_time_dimension_name()] = {
+                self._time_dimensions_to_supported_granularities[
+                    TimeDimensionReference(granularity_free_qualified_name)
+                ].add(time_dimension_instance.spec.time_granularity)
+        self._time_dimensions_to_supported_granularities[DataSet.metric_time_dimension_reference()] = {
             granularity
             for granularity in TimeGranularity
             if granularity.to_int() >= semantic_manifest_lookup.time_spine_source.time_column_granularity.to_int()
@@ -169,23 +171,20 @@ def find_minimum_granularity_for_partial_time_dimension_spec(
                     f"{pformat_big_objects([spec.qualified_name for spec in valid_group_by_elements.as_spec_set.as_tuple])}"
                 )
         else:
-            granularity_free_qualified_name = StructuredLinkableSpecName(
-                entity_link_names=tuple(
-                    [entity_link.element_name for entity_link in partial_time_dimension_spec.entity_links]
-                ),
-                element_name=partial_time_dimension_spec.element_name,
-            ).granularity_free_qualified_name
-
-            supported_granularities = self._time_dimension_names_to_supported_granularities.get(
-                granularity_free_qualified_name
+            time_dim_reference = TimeDimensionReference(
+                StructuredLinkableSpecName(
+                    entity_link_names=tuple(
+                        [entity_link.element_name for entity_link in partial_time_dimension_spec.entity_links]
+                    ),
+                    element_name=partial_time_dimension_spec.element_name,
+                ).granularity_free_qualified_name
             )
+            supported_granularities = self._time_dimensions_to_supported_granularities.get(time_dim_reference)
             if not supported_granularities:
                 raise RequestTimeGranularityException(
                     f"Unable to resolve the time dimension spec for {partial_time_dimension_spec}. "
                 )
-            minimum_time_granularity = min(
-                self._time_dimension_names_to_supported_granularities[granularity_free_qualified_name]
-            )
+            minimum_time_granularity = min(self._time_dimensions_to_supported_granularities[time_dim_reference])
 
         return minimum_time_granularity