Greetings from Classic and Vintage! I recently put together a Free Spirit 10-speed (horizontal dropouts, freewheel hub, etc.) and decided I don't like it, so I'm going to turn it into either a fixed gear or a single-speed. I've read over all the links, but I still have a few (possibly stupid) questions:

Is there a difference between single speed freewheels? (BMX, single speed, "track," etc.)

Will different freewheel thicknesses make much of a difference in how much I have to dish the wheel?

Are "track" freewheels threaded like track cogs or are these intended for the other side of a flip-flop hub? In other words, if I screw one on my 10-speed hub will it only go in reverse?

Is something that is compatible with 1/2 and 3/32" really just 3/32"?

Is there any reason to get a new chain when swapping out gears if the one that's on there is fairly new?

How dangerous is a "suicide hub" fixie, really? Am I going to have problems if I add an English BB lock ring? If I do, do I still need to hose everything down in Lock-tite?
(And why wouldn't you spring for a $3 lockring?)

Sheldon Brown mentioned that some cheap track gears aren't fully threaded. Are there any I should be aware of?

Will using fixed gear put a lot more torque on the crank? Should I consider converting from 1-piece to cotterless if I go this route?

What should I use for a spacer on my axle? I've seen a few builds with what looks like a single anodized spacer, but I haven't been able to find anything like that for sale.

There is a stickied thread about this.

1. Freewheel threading. Singlespeed freewheels with 16t or more are ISO/British thread and 15t and less are Metric. Fixed gear flip flop hubs have ISO threadings on both sides but the "fixed" side have threads for a lockring.

2. I don't think the difference will have too much effect on how much or less you need to re-dish the wheel.

3. A freewheel hub with ISO threading will accept a track cog and a singlespeed freewheel with no problems.

4. Not sure what you mean. Cog/chainring thickness? Chain thickness? Pitch? Please elaborate.

5. Suicide hubs can be safe if it is done properly and have two brakes on. Loc-tite and bb lockring are recommended.

6. Cite the Sheldon source please, not quite sure what you're referring to.

7. I'm no physicist, but I don't think the amount of torque will change just because you are riding fixed gear.

8. Axle spacers should be available at your LBS or bike co-op.

I'm too lazy to look it up now, but I'm pretty sure he's wondering why someone would choose not to add an English thread BB lockring to their "suicide" hub. The reason is that most hubs (the ones I've seen) don't have enough threads for a cog and lockring. So once the cog is on there won't be any threads left for the lockring. IMO, threading a cog onto your hub is the way to go if you want that bike to be fixed gear. It's not worth spending $100+ on a new wheelset. I've done this on conversions before and never had a problem. Once you're certain on your cog selection you can JB Weld it on. If you do it right, it will never come off.

This is very constructive.

3. I had read this and Sheldon referred to "recent" freewheels being ISO, which could mean about anything. Thanks for clearing that up.

4. Disregard that. I had misread a part description showing that a couple freewheels had a wider threaded area, moving the cog outward slightly.

7. Better question: Am I in danger of unthreading the left side cone nut on a 1-piece crank when braking or backpedaling on a fixie?

That makes a lot more sense. From the way he wrote it it sounded like the cog didn't have enough threads and the rest was left blank, potentially stripping the hub if it was screwed on too far. Source is from his fixed gear conversion article.

Also, I was thinking that track hubs were reverse thread compared to a freewheel, hence the question about track freewheel hubs moving in reverse. I didn't realize this was just an issue of having or not having a lock ring.

Man, don't convert it. Build a track bike. Keep that as your road bike. Believe me, you'll end up doing it down the road anyway.

I wasn't trying to be a dick either, just speaking from experience.

I have a 3-speed as my regular ride, and it's much better suited to the roads around here. I was going to sell or give away the 10-speed until I realized how easy converting it would be.

And if I find I need a road bike again, it's just an excuse to buy another bike.

I think OP is referring to using a bb lockring (righty tighty) instead of a normal one (lefty tighty). I would advise against, especially since lockrings are $5.

And if OP isn't, mah bad.

I think the OP is referring to threading a cog onto freewheel hub, and track lefty tighty lockring would not fit on a freewheel hub. Hence the bb lockring.

And if OP is not, my bad as well.

That's exactly what I was referring to. I knew about using the BB lockring on freewheel hubs, but all I'd seen in reference to safety were hubs with no lockring, maybe hosed down in some Loctite or J.B. Weld.

This means track hubs are reverse thread as I thought originally. That would mean a track gear might be ISO thread, but in the wrong direction for my freewheel hub. I could put one on with the outside facing in, right?

Track lockrings are smaller in diameter and there thread pitch is also different from a bb lockring. Only the lockring part of the threads are reverse threaded, the cog part is the regular righty tighty.

So, to sum up:

A track cog is right-hand ISO thread.

A track lock nut is left-hand ISO thread, but it's smaller diameter than the track threads which means the pitch is also a little different.

A BB lockring on a freewheel hub won't hold like a track lockring because it's threaded the same direction as the cog, but its better than nothing.

Cheap track cogs have more threads which means a BB lockring may not fit.

Any freewheel above 15t is ISO and will work on my hub regardless of what it's called.

Regular axle spacers can be used, even though the lack of a freewheel leaves a lot of open space.


I think I'm going to go the single speed route; later on I can switch to fixed. I've got the bike apart and I'll do the conversion after I repaint the frame.

lulz....


@sillygolem.

You got it, that's pretty much the general idea.

I am not sure rather or not if 16t metric BMX freewheel exists though. The most common sizes for metric BMX freewheel are 14 and 15, even some 13. Though, none of them will fit on an ISO/English threaded hub.

Just stay away from metric and you'll be fine.

This seems to be the dividing line: I haven't seen anything 15t or less that is ISO and I haven't seen any 16t metric hubs. I'm going to go with a 17t freewheel and I'll reuse the smaller cog on the crank. This is roughly equivalent to 4th gear with the original freehub.