diff --git a/src/fix_shear_history.cpp b/src/fix_shear_history.cpp
index 21942d753f..17e78830f4 100644
--- a/src/fix_shear_history.cpp
+++ b/src/fix_shear_history.cpp
@@ -389,7 +389,7 @@ void FixShearHistory::pre_exchange_newton()
 
   maxtouch = 0;
   for (i = 0; i < nlocal_neigh; i++) maxtouch = MAX(maxtouch,npartner[i]);
-  comm->maxexchange_fix = MAX(comm->maxexchange_fix,4*maxtouch+1);
+  comm->maxexchange_fix = MAX(comm->maxexchange_fix,(dnum+1)*maxtouch+1);
 
   // zero npartner values from previous nlocal_neigh to current nlocal
 
@@ -590,7 +590,7 @@ int FixShearHistory::pack_reverse_comm_size(int n, int first)
   last = first + n;
 
   for (i = first; i < last; i++)
-    m += 1 + 4*npartner[i];
+    m += 1 + (dnum+1)*npartner[i];
 
   return m;
 }