Roller housings can differ even where doors look alike. Provide the door maker or part reference if known and photograph accessible identification. Do not remove a heavy panel just to obtain a measurement; safe access to the assembly must be planned first.
Some adjustment screws sit behind caps or are obstructed by surrounding finishes. Photograph what is safely visible without dismantling the door. Blocked access can alter the work plan; a damaged adjuster should not be forced to compensate for a worn or incompatible roller.
The wheel shape and diameter must suit the running rail. A visually similar wheel is not enough to establish compatibility. Ordering from an approximate photograph can leave the door unsupported or incorrectly aligned, so confirm the part information before committing to a replacement.
Replace accessible compatible roller assemblies on an accepted panel, set the height and check ordinary travel and stops. Scope limits: Ordinary non-powered safely handled panels only. No heavy specialist lifting, glazing work, powered operators, structural changes or access-control integration.