diff --git a/relay/kusama/src/lib.rs b/relay/kusama/src/lib.rs
index 10403965a2..1b28716d4b 100644
--- a/relay/kusama/src/lib.rs
+++ b/relay/kusama/src/lib.rs
@@ -1307,8 +1307,8 @@ impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
 	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (
-		// Prepare for 128KiB pages and leave space for a header:
-		1 << 17 - 16,
+		// Prepare for 64KiB pages and leave space for a header:
+		(1 << 16) - 16,
 		10 * 1024,
 	);
 	pub const HrmpChannelSizeAndCapacityWithSystemRatio: Percent = Percent::from_percent(100);
diff --git a/relay/polkadot/src/lib.rs b/relay/polkadot/src/lib.rs
index 13c31beb1b..b9f095d1e1 100644
--- a/relay/polkadot/src/lib.rs
+++ b/relay/polkadot/src/lib.rs
@@ -1406,7 +1406,7 @@ impl parachains_dmp::Config for Runtime {}
 parameter_types! {
 	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (
 		// Prepare for 64KiB pages and leave space for a header:
-		1 << 16 - 16,
+		(1 << 16) - 16,
 		1024,
 	);
 	pub const HrmpChannelSizeAndCapacityWithSystemRatio: Percent = Percent::from_percent(100);