Originally Posted by
cyccommute
Is the play in a Tourney derailleur normal? Yes. Should it have that much play? No but Shimano built it that way.
Do yourself a favor and get an Alivio or Acera or Altus rear derailleur. All of them are stiffer…and work better…than a Tourney.
Thank you bike riding scientist. Good info. Appreciate it. I am going to look at upgrading it. I don't want to change the Shimano gear cassette or shifter, so compatibility is key. I could buy another RD-TY21 and see if it's tighter. If not Amazon free return. The derailleur has to be Shimano SiS Index capable. I am hesitant to mix and match brands. Good news these derailleurs are not too expensive.
I am just blown away with how loose the derailleur and integral hanger connection is. I have to admit it works well, quiet, sifts fast and solid. Hummmm if it ain't broke don't fix it comes to mind. At least I know I have options. This may go with the Shimano Uni-glide twisted teeth on the gear set. That is weird as well, but have to admit it shifts better than other bikes I have or had. The question is how long will it last. What ever I do I will need a spare, this derailleur is hanging way out and low on this folding bike. It will eventually get wacked riding it or handling it. Thanks again.