diff --git a/src/openrct2/ride/vehicle.h b/src/openrct2/ride/vehicle.h
index 0f96c0af91..f739990204 100644
--- a/src/openrct2/ride/vehicle.h
+++ b/src/openrct2/ride/vehicle.h
@@ -74,7 +74,7 @@ typedef struct rct_ride_entry_vehicle {
     uint8 car_visual;               // 0x5D , 0x77
     uint8 effect_visual;
     uint8 draw_order;
-    uint8 special_frames;           // 0x60 , 0x7A
+    uint8 special_frames;           // 0x60 , 0x7A, A custom number that can be used rather than letting RCT2 determine it. Needs the VEHICLE_ENTRY_FLAG_HAS_SPECIAL_FRAMES flag set.
     sint8* peep_loading_positions;  // 0x61 , 0x7B
 #ifdef NO_RCT2
     uint16 peep_loading_positions_count;