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geo8rge 05-10-07 09:27 AM

Cheap BMX flip flop to fixed gear conversion
I sort of retracted this post please see:
For an explanation.

If you have a typical BMX flip flop hub with freewheel threads on both sides I think you can convert it to fixed gear.

New! Surly Dingle Two-speed Fixed-gear Sprockets!

The treading works on the freewheel, not fixed, threading.

I bought the Harris Cyclery store brand hub, which is threaded fixed/freewheel but could have just found a used BMX wheel.

senseamp 05-11-07 07:23 AM

You are wrong surely? I have a BMX flip flop hub. I originally got exicited as I thought that meant I could use a fixed-gear sprocket. But what it really is, is two different diameters of freewheel thread, the smaller diameter allows a smaller sprocket. So I got a 13 tooth freewheel sprocket for my Raleigh Twenty build. I'll look into a fixed wheel hub later.

The thing that makes a fixed gear hub is the presence of a slightly small lockring thread on the outside of the hub, with a thread that goes in the opposite direction. You can always use a fixed spocket on a normal freewheel hub, but you won't have a lockring - which is dangerous.


LittlePixel 05-14-07 07:08 AM

bmx flip flops and track flipflops aren't quite the same thing; the threading is a different size so you won't be able to use the same sprockets, nor lock the cog on with a lock ring. However, you could try it out by making a 'suicide hub' which basically entails gluing the cog on with metal glue and then tightening at as tight as is humanly possible using your chain using the 'rotafix' method. I did this on my first foray into fixed gear and it was a reasonable hack though the notion of the glue failing is always in the back of your mind and somewhat unnerving. If you try it and like it I strongly recommend getting a proper track hub and building (or getting your local bike shop / wheel expert) a proper fixed wheel around it. See my Twenty in the sig.

geo8rge 05-14-07 01:25 PM

For the record I bought a Harris Cyclery FF hub. It is threaded for fixed and freewheel on both sides. The Surly Dingle screws on normally, clockwise, on the larger threads used for the freewheel. The lockring I bought, thinking I really needed it, screws onto the smaller diameter thread counter clockwise.

Note if you do not like the unique dingle dual sprocket there are no splines to insert a key to get it off. As you ride you will tighten it. I doubt there is an easy way to get it off. Can you hit a chain wip handle with a hammer?

If you doubt it, pay the $20 to Harris, try it, if it does not thread on return it/exchange it. I think they will take it back 100% unused.

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