EN 14766:2005 - 64_e_stf - Baltik vairas

EN 14766:2005 (E)Dimension in millimetresD 2 ≥ D 1 +10Key1 Chain-wheel discFigure 52 — Chain-wheel disc4.16.2 Chain-wheel disc diameterA chain-wheel disc shall exceed the diameter of the outer chain-wheel, when measured across the tips of the teeth,by not less than 10 mm (see Figure 52).NOTE Where the design is such that the pedal-crank and chain-wheel are too close together to accommodate a full disc, apartial disc may be fitted which closely abuts the pedal-crank.4.16.3 Chain protective deviceA protective device shall, as a minimum, shield the side-plates and top surface of the chain and the chain-wheel fora distance of at least 25 mm rearwards along the chain from the point where the chain-wheel teeth first passbetween the side-plates of the chain and forwards round the outer chain-wheel to a horizontal line passing throughthe bottom-bracket axle centre (see Figure 53).4.16.4 Combined front gear-change guideA combined front gear-change guide and protective device shall, as a minimum, shield the outside face of theupper junction of the chain and outer chain-wheel for a distance of at least 25 mm rearwards along the chain fromthe point where the chain-wheel first passes between the side-plates of the chain (see Figure 53).79