Where fragile or easily marked products are being conveyed on a roller conveyor, it's possible to have plastic rollers fitted. That's fine if the product is light weight, but sometimes that's not the case.
Where the product is heavy or the situation demands that the rollers are wider than normal, plastic roller conveyors may not be strong enough to support the weight. The plastic rollers may cope for a while but over time start to bow, or they may bow right away. If this takes place, the rollers will not run true. But there is a solution. Steel rollers which have the right weight capacity to support the product can be PVC or rubber coated. It's a straightforward process but once done you get the strength of steel roller conveyors with the abrasion resistant properties of plastic or rubber coating.