Garage door bar
 

I am curious as to the one piece torsion tube on my garage door.
It has a single torsion spring on the left with two cable drums on each end.
It was making a clunk sound when near to all the way close.
I disconnected the door from the opener and couldn't find any problems.
I lubed the rollers, spring and the torsion tube where it travels through the cable drums and has seemed to resolved the problem for now.
Anyway, the torsion tube travels about an inch to the right when open and back to the left when closed. These directions of travel are from inside the garage facing towards the road.
I've never really noticed this before and was wondering if this is normal or an indication of something about to go wrong.

Just guessing but if you only have one spring, as it gets tighter it wants to get shorter and pull the rod sideways. If you had two they would be pulling against each other and wouldn't move. Pulleys must be locked to the rod or the spring wouldn't help so someone likely installed them with an extra 1" in there.

As the link Neal provided says there should be no gap between the bearings and the cable drum. The clunk you were hearing may have been the torsion bar slipping from side to side. By lubricating everything it may be moving more freely now and so not clunking. The article talks about stretching the spring before setting the torsion load. That is a new one on me. I have put up several single spring torsion systems and have never heard of that so can't be much help there. Make sure if you decide to release any of the components of the door under pressure from the torsion spring you know how to safely unwind the spring first. You don't want a spring or cable hanging out where your ear used to be.

Found this at this site. https://diygaragerepaircom.uservoice.com/knowledgebase/articles/106918-how-to-wind-your-torsion-springs

Professionals always stretch torsion springs after winding them because the shaft floats horizontally between the flexible end bearing plates as the door operates. Although this may be as little as 1/4", the binding of the coils as the garage door closes oftentimes keeps the door from closing completely, especially when the torsion springs and bearings are dry.