Belt drives mainly bridge large distances between crankshaft(s) and camshaft(s). To prevent the chain from oscillating at drive level, it is guided along rails in the areas between the shafts. The chain tensioner transfers its force to the chain via the moving tensioner blade. The other guides (chain guides) are, in contrast, fixed to the engine. This allows the chain to slide across a plastic sliding layer with minimum friction and wear.
Both the available space and the load on the guide are critical in selecting the material for the guide's supporting substructure. The available options are:
Finite-element calculations and similar analyses help to achieve maximum rigidity at minimum cost and with minimum space. The method of securing the tensioner blades and chain guides to the engine is adjusted to suit individual conditions.