diff --git a/src/main/scala/coreplex/RocketTiles.scala b/src/main/scala/coreplex/RocketTiles.scala
index 60ceb4f3..31f39ba6 100644
--- a/src/main/scala/coreplex/RocketTiles.scala
+++ b/src/main/scala/coreplex/RocketTiles.scala
@@ -73,7 +73,7 @@ trait HasRocketTiles extends CoreplexRISCVPlatform {
       }
       case Rational => {
         val wrapper = LazyModule(new RationalRocketTile(c)(pWithExtra))
-        val sink = LazyModule(new TLRationalCrossingSink)
+        val sink = LazyModule(new TLRationalCrossingSink(util.FastToSlow))
         val source = LazyModule(new TLRationalCrossingSource)
         sink.node :=* wrapper.masterNode
         l1tol2.node :=* sink.node
diff --git a/src/main/scala/rocket/Tile.scala b/src/main/scala/rocket/Tile.scala
index 026564e1..23f726ff 100644
--- a/src/main/scala/rocket/Tile.scala
+++ b/src/main/scala/rocket/Tile.scala
@@ -103,7 +103,7 @@ class RationalRocketTile(rtp: RocketTileParams)(implicit p: Parameters) extends
   masterNode :=* source.node
 
   val slaveNode = TLRationalInputNode()
-  val sink = LazyModule(new TLRationalCrossingSink)
+  val sink = LazyModule(new TLRationalCrossingSink(util.SlowToFast))
   rocket.slaveNode :*= sink.node
   sink.node :*= slaveNode