Chain Rider Set Product Type Chain Rider Set For Chain Number 50 For Number of Strands Single For Chain Pitch 5/8 in Chain Rider Width 63 mm Idler Bolt Thread Size M10 Idler Hole System of Measurement Metric Length through Bore 55 mm Number of Chain Riders 1 Standards ANSI DIN 8187 ISO 10 B-1 Bearing Closure Double Shielded Bore Diameter 10 1/2 mm Chain Number 50 Compatible with Brand Rosta Compatible with Series 18-27