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I bought a commercial grade spin bike (Niuweite F800 from China) for exercising at home during quarantine. I wanted to upgrade the pedals to Shimano pedals since I used to join spinning classes pre-COVID.

However, when I got the pedals, the Shimano pedals have a 9/16" screw size while my spin bike apparently has a much bigger 3/4" socket.

I attempted to buy pedal adapters buy these only go up to 1/2".

Any ideas on what I can do to make my Shimano pedals fit the spin bike? Thanks in advance!

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  • send pics (edit)
    – Swifty
    Nov 1, 2020 at 9:28
  • After some googling, I can't find this brand, let alone this model. Do you have any further information about it ?
    – Criggie
    Nov 1, 2020 at 13:30
  • Did you ever come up with a solution for this? I have the same issue today and this thread is literally the only thing on the entire Internet about this issue. Feb 19, 2021 at 6:38

1 Answer 1

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I've never heard of a 3/4" thread on a pedal on a bicycle. It sounds like they intend for you to buy pedals from the maker of your exercise bike.

However if you are handy, it may be possible to make a pair of adapter bushings from metal.

  • The pedal threads will be 9/16" with 20 TPI (which is not the more common 18TPI) Sadly 20TPI is unique to bicycle pedals, so you're not going to be able to use plumbing parts for this.
  • One has to be left-hand thread for the left pedal's shaft
  • And the outside will have to match the 3/4" and whatever thread pitch is in your bike's cranks. This may be 16 TPI for UNF thread, or 10 TPI for UNC, or something weirder.
  • Also its not guaranteed that your 3/4" threads are opposite-handed.

Given your bike is Chinese, its probably metric for the most part, so there's a chance your pedals have an M18 or an M20 thread, 3/4" is about 19mm so right in the middle of those options. None of them are pedal threads I've heard of though.

This would be a simple job for an engineering firm to fab up from a couple of small disks of steel or maybe aluminium. It would help if you could give them both cranks and both pedals for test-fitting too.


There was a short lived thread of 1 inch, called Shimano Dyna drive. Adapters from that down to 9/16" look like this. Notice the inner is completely within the outer, because there's enough metal to make this possible.

enter image description here

The other option is to stagger them a little as in this 9/16 to 1/2 inch adapter set. Downside of these is they increase your "q-factor" which means your pedals are further apart.

enter image description here

Images are for description of the adaptor required, not a specific product recommendation. Pictured products have the wrong threads for OP's need.

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    The problem with the lower adaptors can be that due to the thickness of the metal you may not be able to tighten your pedals to the adaptor using a hex key and you are out of luck if the pedals do not also have he old-style pedal flats. I do not know if Shimano still makes them, but Crankbrothers do not and so I cannot use my pedal axle extenders I bought. With a larger crank thread diameter it might be possible anyway. Nov 1, 2020 at 8:27
  • @VladimirF Excellent point - I doubt the black ones are hollow through. The point of showin both styles is that the 1/2-9/16 only leaves 1/16th of an inch of material, so not enough meat for nesting. If OP's are 3/4" that's 12/16ths leaving 3/16ths which might be sufficient, but my gut says no.
    – Criggie
    Nov 1, 2020 at 13:28
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    additional option, changing the cranks?
    – Swifty
    Nov 1, 2020 at 15:31
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    My head hurts from all these fractions but the common bushings used to repair stripped crank threads (e. g. parktool.com/blog/repair-help/…) adapt from 10/16" to 9/16". So going from 12/16" (chinese bike) to 9/16" (regular pedal) should be possible. Of course, these are meant to be glued in permanently, so they don't need to accept a wrench.
    – wrtlprnft
    Nov 1, 2020 at 19:00
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    That comment was not in any way meant as criticism of anyone here, sorry if it came across that way. My main point was that it should in principle be possible to make a bushing-type adapter. Whether it's easy or worth it to get the specialized tooling for this (I guess a CNC lathe could do it without special tools), is another matter, of course.
    – wrtlprnft
    Nov 2, 2020 at 5:48

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