I have bowing of my rods when I have a small width warp on a much wider width loom. ie. 12"- 16" warp on 36" loom. Jane seems to do smaller width warps to accommodate the looms of the many guild weavers. (No small feat!) All the torque is at the center, so after tying on I remove the farthest bar ties loosening the tension to do so. Problem solved. I only keep rod ties involved with warp or closest to it. Wooden rods and/ or bars can also warp over time if not used properly. Bowing is a good indicator to pay attention. You must also make adjustments taking into consideration your particular loom & how the apron bar/ rods are spaced & attached. I also remove unnecessary apron cords or straps when lashing since lashing takes even care of warped area. Also, Jane has answered this question before with a different response as I recall but I cannot find it. When I do find it, I will post it for you, If your weaving is uneven, have you checked that the tension is equal on all your bouts? Some may need to be tightened or loosened a bit.