diff --git a/tracy/tracy/src/soleillib.cc b/tracy/tracy/src/soleillib.cc
index 726f4f6f6827e78471849ca7c0217ea86e9a3136..14eaf31444b22e10578769989dce6263ed9e941a 100644
--- a/tracy/tracy/src/soleillib.cc
+++ b/tracy/tracy/src/soleillib.cc
@@ -729,7 +729,7 @@ void TunesShiftWithAmplitude(const char *NudxFile, const char *NudzFile, long Nb
 
     xstep = xmax/Nbx*2.0;
     x0 = 1e-6 - xmax;
-    z0 = 1e-3;
+    z0 = 1e-5;
 
     for (i = 0; i <= Nbx; i++) {
       x  = x0 + i*xstep ;
@@ -770,7 +770,7 @@ void TunesShiftWithAmplitude(const char *NudxFile, const char *NudzFile, long Nb
     fprintf(outf,"#    x[mm]         z[mm]          fx            fy \n");
 
     zstep = ymax/Nby*2.0;
-    x0 = 1e-3;
+    x0 = 1e-5;
     z0 = 1e-6 - ymax;
     for (i = 0; i <= Nby; i++) {
       x  = x0 ;