SHIMANO TIAGRA - Bottom Bracket - Threaded - HOLLOWTECH II - 68/70 mm shell width The SHIMANO TIAGRA bottom bracket uses a new seal construction for long-lasting performance. MODEL NO BB-RS500 SERIES SORA R3000 Series Average weight 92 HOLLOWTECH II bottom bracket_Threaded bottom bracket type ✔ Threaded bottom bracket shell width (mm)_68 ✔ Threaded bottom bracket shell width (mm)_70 ✔