Indoor sliding doors getting harder to open/close

Question

We renovated our house ~2 years ago and had some big full-height indoor sliding doors installed. Hardware for doors is:

• A track recessed into ceiling, from which door is hanging (see photo, top half)
• A track recessed into top of door (see photo, bottom half)
• A track recessed into bottom of door
• Peg in floor + plastic sheathing, fit into bottom track of door.

Problem: The door moves smoothly through most of its path, but as it gets close (~3 inches) to being closed, it is exceedingly difficult to move. I am concerned about someone getting stuck in a room. Seems like an obvious fire hazard, in addition to be annoying. The exact same problem has happened to two of the doors.

I've tried my best to figure out what's going on, but I'm stuck (just like the doors). Notes:

• I was able to see that, even while at the very tight area, the wheel in the upper track is still turning when the door is moving.
• Because these are big, full-height doors, I'm not comfortable removing them from their tracks. I guess if it comes to that, I'll have to get someone to come help.
• I was considering using some WD40 or similar, but I fear that it would attract dirt and make the problem worse. Since I can't take the door of the track to clean things, I assume that this would be a bad idea?

Here is what the upper tracks/wheel look like:

Thank you!

Answer 1

I may have led astray with my photo as the upper track was unrelated to the issue.

It turns out that the peg+plastic sheathing was very tight when at one side of the lower track. Why? The only possibility that I can make sense of is that the door/track itself has contracted on that side. Putting a touch of lubricant just here helped an enormous amount.

Thanks all.