diff --git a/src/engine/surface_collision.c b/src/engine/surface_collision.c
index b695902dc..01f0a3c11 100644
--- a/src/engine/surface_collision.c
+++ b/src/engine/surface_collision.c
@@ -43,7 +43,6 @@ static s32 find_wall_collisions_from_list(struct SurfaceNode *surfaceNode, struc
     register f32 d00, d01, d11, d20, d21;
     register f32 invDenom;
     register f32 v, w;
-    register f32 margin_radius = radius - 1.0f;
     register TerrainData type = SURFACE_DEFAULT;
     s32 numCols = 0;
 
@@ -52,6 +51,8 @@ static s32 find_wall_collisions_from_list(struct SurfaceNode *surfaceNode, struc
         radius = 200;
     }
 
+    f32 margin_radius = radius - 1.0f;
+
     // Stay in this loop until out of walls.
     while (surfaceNode != NULL) {
         surf        = surfaceNode->surface;