Do you have Shimano tourney A070 50/34T 8 speed crankset.
I got this fixed to replace my bike's microshift cassette. The hyperglide machining on the Shimano cassette makes the shifting smoother than before since the microshift cassette did not have the hyperglide type of machining. Also changed the chain to a Shimano 8 speed chain and both the products are well worth the money spent with no 'jumping' of gears during shifting now as compared to earlier on my bike.
Ordered this as it had the original ratio of my RC 120 which was 11 - 34. Shifts are smooth and precise and one does not have to take off all pressure on the pedal to change gear while downshifting. Upshifting is a breeze.