diff --git a/cluster/gce/config-default.sh b/cluster/gce/config-default.sh
index d014395921b..c9175ffd607 100755
--- a/cluster/gce/config-default.sh
+++ b/cluster/gce/config-default.sh
@@ -483,7 +483,7 @@ ROTATE_CERTIFICATES="${ROTATE_CERTIFICATES:-}"
 
 # The number of services that are allowed to sync concurrently. Will be passed
 # into kube-controller-manager via `--concurrent-service-syncs`
-CONCURRENT_SERVICE_SYNCS="${CONCURRENT_SERVICE_SYNCS:-}"
+CONCURRENT_SERVICE_SYNCS="${CONCURRENT_SERVICE_SYNCS:-5}"
 
 export SERVICEACCOUNT_ISSUER="https://kubernetes.io/${CLUSTER_NAME}"
 
diff --git a/cluster/gce/config-test.sh b/cluster/gce/config-test.sh
index 8a862d22578..6c8b84e5b16 100755
--- a/cluster/gce/config-test.sh
+++ b/cluster/gce/config-test.sh
@@ -539,7 +539,7 @@ ROTATE_CERTIFICATES=${ROTATE_CERTIFICATES:-}
 
 # The number of services that are allowed to sync concurrently. Will be passed
 # into kube-controller-manager via `--concurrent-service-syncs`
-CONCURRENT_SERVICE_SYNCS=${CONCURRENT_SERVICE_SYNCS:-}
+CONCURRENT_SERVICE_SYNCS=${CONCURRENT_SERVICE_SYNCS:-5}
 
 # The value kubernetes.default.svc.cluster.local is only usable for full
 # OIDC discovery flows in Pods in the same cluster. For some providers