diff --git a/lib/determine-basal/determine-basal.js b/lib/determine-basal/determine-basal.js
index a254cf8fc..0e6126380 100644
--- a/lib/determine-basal/determine-basal.js
+++ b/lib/determine-basal/determine-basal.js
@@ -417,11 +417,11 @@ var determine_basal = function determine_basal(glucose_status, currenttemp, iob_
             }
             UAMpredBG = UAMpredBGs[UAMpredBGs.length-1] + predBGI + Math.min(0, predDev) + predUCI;
             //console.error(predBGI, predCI, predUCI);
-            // truncate all BG predictions at 3.5 hours
-            if ( IOBpredBGs.length < 42) { IOBpredBGs.push(IOBpredBG); }
-            if ( COBpredBGs.length < 42) { COBpredBGs.push(COBpredBG); }
-            if ( aCOBpredBGs.length < 42) { aCOBpredBGs.push(aCOBpredBG); }
-            if ( UAMpredBGs.length < 42) { UAMpredBGs.push(UAMpredBG); }
+            // truncate all BG predictions at 4 hours
+            if ( IOBpredBGs.length < 48) { IOBpredBGs.push(IOBpredBG); }
+            if ( COBpredBGs.length < 48) { COBpredBGs.push(COBpredBG); }
+            if ( aCOBpredBGs.length < 48) { aCOBpredBGs.push(aCOBpredBG); }
+            if ( UAMpredBGs.length < 48) { UAMpredBGs.push(UAMpredBG); }
             // calculate minGuardBG without a wait from COB if available, or UAM, or IOB predBGs
             if ( (cid || remainingCIpeak > 0) && fractionCOBAbsorbed < 0.75 ) {
                 if ( COBpredBG < minGuardBG ) { minGuardBG = round(COBpredBG); }