There are a few things you will continue to fight with the methods you have employed.
1. The fact the values are EXACTLY the same to four is still not accurate enough. Pro/E is accurate to about 14 places in some instances. Mirroring geometry and goofing with the accuracy will reduce it however...but on the bad side.You may have a graphically exact "match" between the features but it isn't exact. You simply will have no end of trouble with the geometry at this point.
2. The torroidal bend is a "normalizing" feature, I beleive. In other words, the thickness has a normal cross section across its thickness. The system is trying to resolve the intersecting areas and can't quite get there. The geometry is falling outside the reasonable mathematicalparameters and accuracywhich is why you are getting the "no more geometry" possible error. To answer your question...yes the torroidial bend is limiting. You should limit it use unless it give you EXACTLY waht you need. It has its place. It was developed for tireengineering so it sounds like it's warranted here.
I think I can help you get to the goal. Try the following:
I assume you need to see the tread in a flat configuration at some point. The trick here is to remove the link between the carcass and the torroid to avoid failure, but have the torroid and carcass mergedlater...which is a definite reference.This is where it get's tricky and sneaky.
You may need to redo a few things but it can be done. You are in WF2 so the redefinition steps should be minor.You should redefine the tread component as a surface model with the treads merged in after the first surface. Create the torroid. Create the surfaces that will "complete" the part and then create a protrusion by merging the features up to and including the torroid with the merged features after the torroid. Create instances that has the final solid as the generic and one with features up to the torroid regenerated. In other words,theinstance islike being in insert mode just after the torroid. That part is done.
Create an assembly. Add instance of the torroid part FIRST. Assemble the carcass component and redefine the revolve as a surface and align your sectionto the edge of the surface of the torroid. I don't know how much you have built past the revolve of the carcass but hopefully its not too much. It's just busy work getting things back into place. As a check, create an assembly feature that merges the torroid and carcass. If it works then you are on the right track. Delete the assembly merge.If not will need to redo the carcass partas a sweep that "uses the edge" of the torroid in side view instead of profile. You could rebuild the carcass pretty easily I assume if you had to. If the assembly merge worked then go to the carcass part and "complete" the model like the torroid. Create an instance with the generic being the completed solid. Go back to the assembly and re-assemble the carcass instance with the torroid surfaces. You can merge the parts together as surfaces and then create an assembly featrure that makes it a solid.
You could create a new part too if you wanted and merge in the surfs from the assembly. However your designs, should follow what the manufacturing process steps are. You don't want to create irrelevant assemblies or parts that have to be tracked for years.
I know I threw a ton at you. If you need some further assistance contact me.