A couple of years ago I have replaced the roller carriages for my glass sliding door with a pair of RollTrack rollers like the ones in the photo below. Today, the door has slowly gone back to being hard to slide open exactly as it used to be two years ago. When I have replaced the rollers, I levelled the rollers' height to the best I could do (hardly any gap between top and botttom less than 3mm). I am also having the same problem with sliding window rollers replaced with RollTrack ones around the same time.
Now, I don't suppose rollers needs replacing every couple of years, so I appreciate any pointers on what I could be missing , or recommendations for different brand rollers.
