Having registration issues when a lead is barred

[paperhat]

We have a double wide press with color towers. When the sheet has a full bar or a dinky bar, our side to side registration gets much worse. We can get one half of the lead to fit fine, but the cyan and magenta on the barred half needs to be let out a mile but we have no more adjustment on our bustle wheels. It is almost like the opposite of fan-out. We have put on new blankets and torqued them and this has not helped at all. Any ideas? I do not understand how using angle bars would affect registration in the unit.

[gordo]

Is the misregistration consistent? If so it can be compensated for in prepress.