diff --git a/pkg/http/handler/timeout.go b/pkg/http/handler/timeout.go
index f864a07fb268..bc8b6d308bcc 100644
--- a/pkg/http/handler/timeout.go
+++ b/pkg/http/handler/timeout.go
@@ -127,9 +127,8 @@ func (h *timeoutHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 		case <-timeout.C():
 			timeoutDrained = true
-			if tw.tryTimeoutAndWriteError(h.body) {
-				return
-			}
+			tw.forceTimeoutAndWriteError(h.body)
+			return
 		case now := <-idleTimeoutCh:
 			timedOut, timeToNextTimeout := tw.tryIdleTimeoutAndWriteError(now, revIdleTimeout, h.body)
 			if timedOut {
@@ -214,22 +213,10 @@ func (tw *timeoutWriter) WriteHeader(code int) {
 	tw.w.WriteHeader(code)
 }
 
-// tryTimeoutAndWriteError writes an error to the responsewriter if
-// nothing has been written to the writer before. Returns whether
-// an error was written or not.
-//
-// If this writes an error, all subsequent calls to Write will
-// result in http.ErrHandlerTimeout.
-func (tw *timeoutWriter) tryTimeoutAndWriteError(msg string) bool {
+func (tw *timeoutWriter) forceTimeoutAndWriteError(msg string) {
 	tw.mu.Lock()
 	defer tw.mu.Unlock()
-
-	if tw.lastWriteTime.IsZero() {
-		tw.timeoutAndWriteError(msg)
-		return true
-	}
-
-	return false
+	tw.timeoutAndWriteError(msg)
 }
 
 // tryResponseStartTimeoutAndWriteError writes an error to the responsewriter if
diff --git a/pkg/http/handler/timeout_test.go b/pkg/http/handler/timeout_test.go
index b388e94d5ddd..aa0cbb2b4cce 100644
--- a/pkg/http/handler/timeout_test.go
+++ b/pkg/http/handler/timeout_test.go
@@ -34,8 +34,6 @@ func TestTimeoutWriterAllowsForAdditionalWritesBeforeTimeout(t *testing.T) {
 	clock := clock.RealClock{}
 	handler := &timeoutWriter{w: recorder, clock: clock}
 	handler.WriteHeader(http.StatusOK)
-	handler.tryTimeoutAndWriteError("error")
-	handler.tryResponseStartTimeoutAndWriteError("error")
 	handler.tryIdleTimeoutAndWriteError(clock.Now(), 10*time.Second, "error")
 	if _, err := io.WriteString(handler, "test"); err != nil {
 		t.Fatalf("handler.Write() = %v, want no error", err)
diff --git a/test/conformance/api/v1/revision_timeout_test.go b/test/conformance/api/v1/revision_timeout_test.go
index 6c8097559515..221c7ed020c8 100644
--- a/test/conformance/api/v1/revision_timeout_test.go
+++ b/test/conformance/api/v1/revision_timeout_test.go
@@ -37,7 +37,7 @@ import (
 
 // sendRequest send a request to "endpoint", returns error if unexpected response code, nil otherwise.
 func sendRequest(t *testing.T, clients *test.Clients, endpoint *url.URL,
-	initialSleep, sleep time.Duration, expectedResponseCode int) error {
+	initialSleep, sleep time.Duration, expectedResponseCode int, expectedBody string) error {
 	client, err := pkgtest.NewSpoofingClient(context.Background(), clients.KubeClient, t.Logf, endpoint.Hostname(), test.ServingFlags.ResolvableDomain, test.AddRootCAtoTransport(context.Background(), t.Logf, clients, test.ServingFlags.HTTPS))
 	if err != nil {
 		return fmt.Errorf("error creating Spoofing client: %w", err)
@@ -68,7 +68,12 @@ func sendRequest(t *testing.T, clients *test.Clients, endpoint *url.URL,
 	if expectedResponseCode != resp.StatusCode {
 		return fmt.Errorf("response status code = %v, want = %v, response = %v", resp.StatusCode, expectedResponseCode, resp)
 	}
-
+	if expectedBody != "" {
+		gotBody := string(resp.Body)
+		if expectedBody != gotBody {
+			return fmt.Errorf("response body = %v, want = %v, response = %v", gotBody, expectedBody, resp)
+		}
+	}
 	return nil
 }
 
@@ -99,6 +104,7 @@ func TestRevisionTimeout(t *testing.T) {
 		expectedStatus: http.StatusOK,
 		sleep:          15 * time.Second,
 		initialSleep:   0,
+		expectedBody:   "activator request timeout",
 	}}
 
 	for _, tc := range testCases {
@@ -136,7 +142,7 @@ func TestRevisionTimeout(t *testing.T) {
 				t.Fatalf("Error probing %s: %v", serviceURL, err)
 			}
 
-			if err := sendRequest(t, clients, serviceURL, tc.initialSleep, tc.sleep, tc.expectedStatus); err != nil {
+			if err := sendRequest(t, clients, serviceURL, tc.initialSleep, tc.sleep, tc.expectedStatus, tc.expectedBody); err != nil {
 				t.Errorf("Failed request with initialSleep %v, sleep %v, with revision timeout %ds, expecting status %v: %v",
 					tc.initialSleep, tc.sleep, tc.timeoutSeconds, tc.expectedStatus, err)
 			}