diff --git a/pkgs/racket-test-core/tests/racket/sync.rktl b/pkgs/racket-test-core/tests/racket/sync.rktl
index c7d1220aef..51e27d4ab5 100644
--- a/pkgs/racket-test-core/tests/racket/sync.rktl
+++ b/pkgs/racket-test-core/tests/racket/sync.rktl
@@ -234,12 +234,16 @@
 	    (wrap-evt
 	     (alarm-evt (+ (current-inexact-milliseconds) (* 1000 amt)))
 	     (lambda (v) amt)))))])
-  (test #f sync/timeout 0.1 (make-delay 0.15) (make-delay 0.2))
-  (test 0.15 sync/timeout 18 (make-delay 0.15) (make-delay 0.2))
-  (test 0.15 sync/timeout 18 (make-delay 0.2) (make-delay 0.15))
-  (test 0.15 sync/timeout 0.18 (make-delay 0.15) (make-delay 0.2))
-  (test 0.15 sync/timeout 18 
-	(choice-evt (make-delay 0.2) (make-delay 0.15))))
+  (define fast SYNC-SLEEP-DELAY)
+  (define slow1 (* 100 SYNC-SLEEP-DELAY))
+  (define slow2 (* 99 SYNC-SLEEP-DELAY))
+  (test #f sync/timeout fast (make-delay slow1) (make-delay slow1))
+  (test fast sync/timeout slow1 (make-delay fast) (make-delay slow2))
+  (test fast sync/timeout slow1 (make-delay slow2) (make-delay fast))
+  (test fast sync/timeout slow2 (make-delay fast) (make-delay slow1))
+  (test fast sync/timeout slow2 (make-delay slow1) (make-delay fast))
+  (test fast sync/timeout slow2
+	(choice-evt (make-delay slow1) (make-delay fast))))
 
 ;;check flattening of choice evts returned by a guard:
 (let ()