What derailleurs (brand and model) are you using? I've used virtually only SunTours since 1973 and haven't seen that issue if cables, housing were in good order and the pivots in good shape. Granted, I have tended to smaller FWs and have yet to go bigger than 28 teeth. Had a housemate with a SunTour RD'd bike and the Shimano FW with the huge jump to the enormous cog and it did the shift with little effort.