diff --git a/web/ons-demo/js/iperf.js b/web/ons-demo/js/iperf.js
index b1f964c..54c87ea 100644
--- a/web/ons-demo/js/iperf.js
+++ b/web/ons-demo/js/iperf.js
@@ -49,9 +49,9 @@
 					continue;
 				}
 
-				var y = 28 * sample.value/1000000;
-				if (y > 28) {
-					y = 28;
+				var y = 24 * sample.value/1000000;
+				if (y > 24) {
+					y = 24;
 				}
 				if (i == iperfData.samples.length - 1) {
 					d = 'M' + x + ',30';