diff --git a/segmentmodel.py b/segmentmodel.py
index 3ad950f64f068a5cb7c12e5813457d3693a18d85..6230eab8bdd0c8345d4a40fb3454e3249d7f3fb7 100644
--- a/segmentmodel.py
+++ b/segmentmodel.py
@@ -1622,7 +1622,7 @@ class SegmentModel(ArbdModel):
                 k = opt.leastsq( fitFun, x0=np.exp(-sep/Lp) )
                 k = k[0][0] * 2*kT*0.00030461742
                         
-                t0 = sep*(360.0/s1.twist_per_nt)
+                t0 = sep*s1.twist_per_nt # TODO weighted avg between s1 and s2
                 
                 # pdb.set_trace()
                 if A1.on_fwd_strand: t0 -= 120