I have a flip flop hub and I'd like to convert the fixed side to be free wheel. Is this possible? If so how much might it cost?

My motivation for this is that:

  1. I never ride fixie
  2. I'm running a 46/16 and would like to have a lower gear ratio (46/17 or 46/18). It would be really nice if I could keep the 46/16 and just flip the hub to have a different gear ratio.

enter image description here

  • White Industries makes double freewheels (the Eno Dos), which you put on one side and get two ratios.
    – Batman
    Commented Sep 20, 2016 at 1:02
  • I too would be interested in something like this. My single gear bike is terrible for even the smallest hills. A lower gear would be nice.
    – npsantini
    Commented Sep 20, 2016 at 10:17
  • Does anyone know the thread sizes for freewheel and fixed? It seems like there should be a way to do this, but so far I have found nothing.
    – npsantini
    Commented Sep 20, 2016 at 15:13
  • you might apply carbon fiber and rethread. same as a bottom bracket repair? dunno, just thought of it.
    – brucie
    Commented Mar 6, 2019 at 16:01

2 Answers 2


You can just use the freewheel on the large thread on the fixed side. It's the same size, and just as durable as the freewheel side, for normal people.

So just unscrew the lockring and cog, and put on a standard freewheel of your choice. Did it as a bike messenger, and it still holds to this day.

Happy riding!

  • This is the answer, however, according to my LBS there is a downside to doing this. The bolt threading on the fixed wheel side is shorter than what the freewheel is designed for. This means that freewheel will be tight but only "half threaded" if you will. The LBS said they would do it if I wanted but that it greatly increases the likelihood of potentially catastrophic component failure.
    – LeviX
    Commented Sep 23, 2016 at 2:43
  • 1
    It might be half of available threads for freewheel, but it's still same amount of threads that is used with track cog and durable enough for track sprinters.
    – ojs
    Commented Oct 2, 2016 at 18:04
  • @ojs Good point hadn't thought of it that way. I guess I thought the teeth on a free wheel were a little further out from the wheel hub than on a track cog, thus not having as many threads would be an issue. However, I think it will be fine.
    – LeviX
    Commented Oct 2, 2016 at 21:21

As a follow up, I actually did put the freewheel on the fixed gear side (after some cleaning). As you can see from the pictures, the freewheel won't be all the way threaded (like my LBS said) but it feels secure enough.

As far as tools required:

enter image description here

enter image description here

  • Remember its a freewheel so you're not braking with this at all - there's no undo-torque applied by the chain. Could be a good project for a hobby machinist to turn a chunky spacer and thread the inside and the outside to tolerance.
    – Criggie
    Commented May 6, 2019 at 7:53

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