3/4" Round Shower Door Wheel

I don't see any marking. The wheel is 3/4" diameter. The doors are older and heavy. Should I replace the entire system, or do you have replacement parts for this?

I'm trying to find 2 replacement parts to a shower door. The shower door is from a company called Royal Guard Bath

Please refer to pictures attached. The most critical measure is the distance between the bolt center that goes through the glass and the inner bottom (if you invert the picture) of the "U" shape that hugs the top of the glass door - that is a bit more than 3/4" (13/16" to 7/8"); I guess this distanc ... (cont.)

Looking to replace these, our shower doors are old but still in good shape besides these rollers

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