Just took my old 1983 12 speed out of mothballs. put on 94 miles this month very hilly here. My question is:

can I upgrade my freewheel with Shimano MF-TZ31 Tourney Freewheel (14-34T Mega 7 Speed)?

Would I also have to upgrade my chain, derrailer, and front gears? currently have Shimano on it. It was not a fancy bike no quick release on rear (just to give you an idea of cost of bike).

I can do my own maintenance but I would need detailed part info not sure what goes with what. any help would be appreciated.

  • 2
    If you don't know anything about the current setup, photos could help.
    – ojs
    Jul 22, 2017 at 17:50
  • You should probably post some photos.
    – Batman
    Jul 23, 2017 at 23:44

1 Answer 1


It is do-able at a reasonable cost if you do the work yourself. Your current derailleur likely does not have the tooth capacity for a 14-34t freewheel. The mount on a new derailleur wont mount to your bike if it uses the older style that is held by the axle nuts. Luckily there is an adapter available for about $5. Your chain will also be too short and too wide for for the new rear cog . The narrower 7 speed chain should work with your current crank. You will also need an appropriate freewheel tool and chain whip to remove the freewheel. A local bike shop may do this task for less than the cost of buying the tools. If you are using friction (non index) shifters they will also work. Based on average EBay prices of less than $20 each for a derailleur, chain and freewheel you will invest less than $100. The plus is when you are done you will know how to install and adjust the derailleur, shorten the chain some basic tuning.

  • Thanks Mike I found the chain and freewheel on Ebay like you said the derailleur though I am confused should it say 34t on it? would like to stay with Shimano but I don't quite understand the lingo
    – daveg
    Jul 22, 2017 at 21:03
  • Either Shimano Altus or Acera (RD M360) will be affordable. This is the low end of Shimano's line, but still fully functional. They come with a long cage meaning they will work with your freewheel. The description may also include MegaRange in the description.
    – mikes
    Jul 22, 2017 at 21:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.