diff --git a/cortex/dataset/view2D.py b/cortex/dataset/view2D.py
index 6a41792ac..341c7c50a 100644
--- a/cortex/dataset/view2D.py
+++ b/cortex/dataset/view2D.py
@@ -57,8 +57,10 @@ def to_json(self, simple=False):
         d1js = self.dim1.to_json()
         d2js = self.dim2.to_json()
         sdict.update(dict(
-            vmin = [[self.vmin or d1js['vmin'][0], self.vmin2 or d2js['vmin'][0]]],
-            vmax = [[self.vmax or d1js['vmax'][0], self.vmax2 or d2js['vmax'][0]]],
+            vmin = [[d1js['vmin'][0] if self.vmin is None else self.vmin,
+                     d2js['vmin'][0] if self.vmin2 is None else self.vmin2]],
+            vmax = [[d1js['vmax'][0] if self.vmax is None else self.vmax,
+                     d2js['vmax'][0] if self.vmax2 is None else self.vmax2]],
             ))
 
         if "xfm" in d1js:
diff --git a/cortex/tests/test_dataset.py b/cortex/tests/test_dataset.py
index d3224bd4f..0e3d03691 100644
--- a/cortex/tests/test_dataset.py
+++ b/cortex/tests/test_dataset.py
@@ -154,6 +154,36 @@ def test_2D():
     twod.to_json()
 
 
+def test_2D_to_json_keeps_explicit_zero_limits():
+    """to_json must keep an explicitly requested limit of 0 for all four bounds.
+
+    0 is falsy, so a fallback written with ``or`` silently replaces it with the
+    data range taken from the underlying dim.
+    """
+    d1 = cortex.Volume.random(subj, xfmname)
+    d2 = cortex.Volume.random(subj, xfmname)
+
+    # Control: nonzero limits are already passed through untouched.
+    control = cortex.Volume2D(d1, d2, vmin=1, vmax=3, vmin2=2, vmax2=4)
+    assert control.to_json()["vmin"] == [[1, 2]]
+    assert control.to_json()["vmax"] == [[3, 4]]
+
+    view = cortex.Volume2D(d1, d2, vmin=0, vmax=0, vmin2=0, vmax2=0)
+    assert view.to_json()["vmin"] == [[0, 0]]
+    assert view.to_json()["vmax"] == [[0, 0]]
+
+    v1 = cortex.Vertex.random(subj)
+    v2 = cortex.Vertex.random(subj)
+
+    control = cortex.Vertex2D(v1, v2, vmin=1, vmax=3, vmin2=2, vmax2=4)
+    assert control.to_json()["vmin"] == [[1, 2]]
+    assert control.to_json()["vmax"] == [[3, 4]]
+
+    view = cortex.Vertex2D(v1, v2, vmin=0, vmax=0, vmin2=0, vmax2=0)
+    assert view.to_json()["vmin"] == [[0, 0]]
+    assert view.to_json()["vmax"] == [[0, 0]]
+
+
 def test_braindata_hash():
     d = cortex.Volume.random(subj, xfmname)
     hash(d)