Shimano Rear Derailleur 7-Speed RD-A070 ADPT with Mounting Bracket Black -H
£11.29
This derailleur is generally compatible with Total capacity = (large chainring - small chainring) + (large rear cog - small rear cog). 50/34T front with 11-28T rear (gives 50-34 = 16 + 28-11 = 17 → 16+17 = 33T → maxing out capacity).
