Chain sprockets 85 Chain sprockets 820-831 B 1.89/48 2.09/53 0.59/15 OD PD S B 1.89/48 2.09/53 0.59/15 OD PD S Split idler sprocket, molded Part Article-Nr. Z- Bore in PD in-mm OD in-mm S in-mm 542 54251Y 21 1 5.09/129,3 5.08/129,0 2.67/67,8 542 54252Y 1¹⁄₄ 542 54253Y 1⁷⁄₁₆ 542 54254Y 1¹⁄₂ 543 54351Y 23 1 5.56/141,2 5.60/142,0 2.90/73,8 543 54352Y 1¹⁄₄ 543 54353Y 1⁷⁄₁₆ 543 54354Y 1¹⁄₂ 544 54451Y 25 1 6.03/153,2 6.06/154,0 3.14/79,8 544 54452Y 1¹⁄₄ 544 54453Y 1⁷⁄₁₆ 544 54454Y 1¹⁄₂ Material: Reinforced polyamide Screws: Stainless steel Nuts: Zinc plated steel 820-831 Split drive sprocket, molded Part Article-Nr. Z- Bore in PD in-mm OD in-mm S in-mm 542 54201Y 21 1 5.09/129,3 5.08/129,0 2.67/67,8 542 54202Y 1¹⁄₄ 542 54203Y 1⁷⁄₁₆ 542 54204Y 1¹⁄₂ 543 54301Y 23 1 5.56/141,2 5.60/142,0 2.90/73,8 543 54302Y 1¹⁄₄ 543 54303Y 1⁷⁄₁₆ 543 54304Y 1¹⁄₂ 544 54401Y 25 1 6.03/153,2 6.06/154,0 3.14/79,8 544 54402Y 1¹⁄₄ 544 54403Y 1⁷⁄₁₆ 544 54404Y 1¹⁄₂ Improved Design and Performance Improved Design and Performance