diff --git a/lib/Sub/Rate/NoMaxRate.pm b/lib/Sub/Rate/NoMaxRate.pm
index 7db3939..40333f4 100644
--- a/lib/Sub/Rate/NoMaxRate.pm
+++ b/lib/Sub/Rate/NoMaxRate.pm
@@ -7,6 +7,15 @@ use List::Util 'sum';
 
 extends 'Sub::Rate';
 
+before add => sub {
+    my ($self, $rate) = @_;
+
+    my $max_rate = sum map { $_->[0] } @{ $self->_func };
+    $max_rate += $rate;
+    $self->max_rate($max_rate);
+};
+
+
 before generate => sub {
     my ($self) = @_;
 
diff --git a/t/nomaxrate.t b/t/nomaxrate.t
index 2f374d9..6473124 100644
--- a/t/nomaxrate.t
+++ b/t/nomaxrate.t
@@ -22,4 +22,9 @@ is $loop_count, $r1 + $r2, 'loop count same as $r1 + $r2';
 
 ok 2.0*0.95 <= $r2 / $r1 && $r2 / $r1 <= 2.0*1.05, '$r2/$1 about 20/10 ok';
 
+$sub->clear;
+
+eval { $sub->add(1000 => sub {}) };
+ok !$@, 'no error ok (over default max_rate)';
+
 done_testing;