UNECE R90, covering key replacement components for brakes, is closely tied to UNECE R13/R13-H and R78 governing brake systems for commercial/passenger vehicles and motorcycles, respectively. The drum-brake lining provisions apply specifically to medium and heavy vehicles and trailers.

While this rule addresses situations specific to replacement brake linings, these products may alternatively be approved through UNECE R13/13-H or R78. Consequently, products approved under the above rules do not require subsequent reapproval under UNECE R90 for use in vehicle maintenance.

However, such brake components that have not been approved under UNECE R13 or R78 and which are intended for vehicles approved under those rules must comply with UNECE R90.