diff --git a/collects/tests/typed-scheme/unit-tests/typecheck-tests.rkt b/collects/tests/typed-scheme/unit-tests/typecheck-tests.rkt
index 6c82cc3c..7f2efe54 100644
--- a/collects/tests/typed-scheme/unit-tests/typecheck-tests.rkt
+++ b/collects/tests/typed-scheme/unit-tests/typecheck-tests.rkt
@@ -148,10 +148,10 @@
         (tc-e/t 3 -PositiveFixnum)
         (tc-e/t 100 -PositiveFixnum)
         (tc-e/t -100 -NegativeFixnum)
-        (tc-e/t 2147483647 -PositiveFixnum)
-        (tc-e/t -2147483647 -NegativeFixnum)
-        (tc-e/t 2147483648 -Pos)
-        (tc-e/t -2147483648 -Integer)
+        (tc-e/t 1073741823 -PositiveFixnum)
+        (tc-e/t -1073741824 -NegativeFixnum)
+        (tc-e/t 1073741824 -Pos)
+        (tc-e/t -1073741825 -Integer)
         (tc-e/t "foo" -String)
         (tc-e (+ 3 4) -Pos)
         [tc-e/t (lambda: () 3) (t:-> -PositiveFixnum : -true-lfilter)]
diff --git a/collects/typed-scheme/typecheck/tc-expr-unit.rkt b/collects/typed-scheme/typecheck/tc-expr-unit.rkt
index e09a06d9..1ede210e 100644
--- a/collects/typed-scheme/typecheck/tc-expr-unit.rkt
+++ b/collects/typed-scheme/typecheck/tc-expr-unit.rkt
@@ -27,8 +27,8 @@
 ;; `fixnum?' to avoid creating platform-dependent .zo files.
 (define (portable-fixnum? n)
   (and (exact-integer? n)
-       (< n (expt 2 31))
-       (> n (- (expt 2 31)))))
+       (< n (expt 2 30))
+       (>= n (- (expt 2 30)))))
 
 ;; return the type of a literal value
 ;; scheme-value -> type