EDGE DISTANCE

Edge distance is the lateral gap between the outer edge of the belt and any vertical structure on either side — the skirtboard rubber at the loading chute, the sidewall plates of a covered conveyor, or simply the stringer of an open gallery. Adequate edge distance is essential because belts mistrack to some degree on every run, and a belt that runs against a hard structure abrades its edge, damages its carcass, and ultimately tears. Adequate edge distance also leaves a 'load reserve' so that a belt running slightly off-centre still keeps the material heap within the belt width rather than spilling it over the trough rim.

Standard edge-distance guidance: at the loading chute skirts, leave 50–75 mm clear of the belt edge on each side; through the carry run, 75–100 mm to fixed structure; at any covered or partially enclosed gallery, 100 mm minimum to the cover wall. Edge distance should be added to material-loaded width when sizing the belt — a belt sized only to the calculated material width will spill at every transient mistracking event.

On belts that run with [sidewalls](/products/sidewall-belts) (corrugated sidewall design), 'edge distance' instead refers to the unused belt width outside the sidewall foot — typically 30–50 mm — used as the pulley contact band, since the corrugated wall cannot itself wrap around a pulley. Selecting the right edge distance is one of the first checks during conveyor commissioning; insufficient clearance is a leading cause of accelerated belt-edge failure.