An Engineering Problem

[Technochicken]

http://img684.imageshack.us/img684/5554/p6110250.jpg

As most of you will notice, this is a bicycle wheel. A very old and very nice one at that.

This is a picture of the wheel's hub:

http://img121.imageshack.us/img121/4605/p6110251.jpg

And two more. Note the threads on the hub:

http://img294.imageshack.us/img294/8473/p6110252.jpg
http://img695.imageshack.us/img695/5522/p6110253.jpg

This is a lockring that happens to fit the threads:

http://img30.imageshack.us/img30/9863/p6110256.jpg

Threaded on:

http://img687.imageshack.us/img687/6194/p6110257.jpg
http://img88.imageshack.us/img88/9282/p6110258.jpg

And here is the problem:

The threads on the hub are right handed: when you spin the lockring right it tightens, left it loosens. What I need to do is somehow fix the lockring so that it will stay in place no matter what direction it is turned. When it is locked, the wheel must be able to spin freely around the bearings. Also, as the hub is nearly 40 years old, in great condition, and made by one of the best hub makers ever, I would rather not fix it in place using glue, thread locker, welding, or anything else that would be permanent or damage the hub. Eventually I will be using a cog instead of a lockring, but as of now that is the only thing I have that threads onto the hub.

I purposefully did not use the exact terminology for these parts I am using, so that you guys don't just look the problem up on Google. Believe me, I have done that, and now it is very hard for me to think of anything else but what I have read on the internet.

Thanks for any help!

-Technochicken

[x88x]

If you can get another lockring and tighten the two against each other, that'll hold them in place.

[Airbozo]

If you can get another lockring and tighten the two against each other, that'll hold them in place.

Ditto.

[Diamon]

Another solution might be to somehow get your hands on a lockring with rubber in it, dunno really what it's called. Anyways they're really hard to turn so it won't loosen, or tighten easily. But using two lockrings as x88x said is probably a better solution.

[Technochicken]

I have thought about that, but there are a few problems with using a lockring and a cog on the hub. First of all, there is not always space for both on the threads- I can probably get thinner cogs though- and secondly, there will be a LOT of force against it while spinning the opposite direction. I am trying to convert the wheel to a fixed gear, and with those you can slow down with your legs. This can easily put more force on the cog than accelerating can, so I'm not sure that just having a cog plus a lockring would hold against that much force. I'll see if i can get my hands on another lockring and try that, but I'm doubtful it would work safely.

[SXRguyinMA]

if you can get a small hex-head set screw, drill and tap the lockring so when it's tight, you tighten the set screw :D

http://www.mcmaster.com/#screw-sets/=7hntmg

[Technochicken]

if you can get a small hex-head set screw, drill and tap the lockring so when it's tight, you tighten the set screw :D

http://www.mcmaster.com/#screw-sets/=7hntmg

I'm not exactly sure what you mean. Do you mean set the screw parallel to the edge of the ring, so it can compress the lockring, i.e. reduce it's diameter by tightening it? If there is space for that it might actually work.

[dr.walrus]

if you can get a small hex-head set screw, drill and tap the lockring so when it's tight, you tighten the set screw :D

http://www.mcmaster.com/#screw-sets/=7hntmg


Screw the nut into the bolt using a secondary fixing?

GENIUS. DO THIS.

Might need some new tools! And some new fixings!

[dr.walrus]

I have thought about that, but there are a few problems with using a lockring and a cog on the hub. First of all, there is not always space for both on the threads- I can probably get thinner cogs though- and secondly, there will be a LOT of force against it while spinning the opposite direction. I am trying to convert the wheel to a fixed gear, and with those you can slow down with your legs. This can easily put more force on the cog than accelerating can, so I'm not sure that just having a cog plus a lockring would hold against that much force. I'll see if i can get my hands on another lockring and try that, but I'm doubtful it would work safely.

would be fine with nylocks on both. Probably. Maybe.

[Technochicken]

would be fine with nylocks on both. Probably. Maybe.

Maybe. It's a lot of force though. Also, I'm not sure one would even fit along with a cog, given the relatively small amount of thread on the hub. But this screw idea seems interesting, although I don't fully understand it.

[SXRguyinMA]

drill in from the notched side to the threaded side, and use a small set screw. you tighten the screw and it puts pressure against the threads on the hub to secure it. along the idea of this:

http://www.climaxmetal.com/images/C-2H_170.jpg

as long as there's enough thickness in the ring to be able to do it that is

:EDIT: hell, even find one of those collars the right size! thread on the ring and tighten it, then slip on that collar and tighten the set screws, that will keep the ring from loosening!

[dr.walrus]

whilst this represents a massive over-simplication, I think this might be what was suggested.

http://img809.imageshack.us/img809/7566/65106546.jpg (http://img809.imageshack.us/i/65106546.jpg/)

Screw it on, tighten it up, drill and tap, put in a screw.

[dr.walrus]

drill in from the notched side to the threaded side, and use a small set screw. you tighten the screw and it puts pressure against the threads on the hub to secure it. along the idea of this:

http://www.climaxmetal.com/images/C-2H_170.jpg


as long as there's enough thickness in the ring to be able to do it that is

Yeah. Like that. But you could make your own to suit you situation or to tighten directly into the thread or hub itself, if you're worried about stripping the threads

[Technochicken]

drill in from the notched side to the threaded side, and use a small set screw. you tighten the screw and it puts pressure against the threads on the hub to secure it. along the idea of this:

http://www.climaxmetal.com/images/C-2H_170.jpg

as long as there's enough thickness in the ring to be able to do it that is

:EDIT: hell, even find one of those collars the right size! thread on the ring and tighten it, then slip on that collar and tighten the set screws, that will keep the ring from loosening!


That's a good idea, but would that damage the threads on the hub?

[SXRguyinMA]

thats not a bad idea either walrus. Although next time you remove/reinstall it those two holes may not line up, and there may not be enough material on the hub to drill into :?

[SXRguyinMA]

That's a good idea, but would that damage the threads on the hub?

not with a setup like that. with 2 screws you only need a small amount of pressure on each, not enough to mess up the threads unless you put the screws in with an air impact gun lol

[dr.walrus]

thats not a bad idea either walrus. Although next time you remove/reinstall it those two holes may not line up, and there may not be enough material on the hub to drill into :?

they should line up, but the 'enough material' is a valid issue and depends utterly on the setup itself.

Grub screws would do the job but I wouldn't be 100% on relying on them

[Technochicken]

If I were to put a screw through the cog (because the lockring was just as an example), there is a problem because there is a lip on one side of the cog. This means you can't screw it flush with the flanges on the hub.

example:
http://www.burkescycles.co.nz/mm5/graphics/s/surly_track_cog_large.jpg

[dr.walrus]

If I were to put a screw through the cog (because the lockring was just as an example), there is a problem because there is a lip on one side of the cog. This means you can't screw it flush with the flanges on the hub.

example:
http://www.burkescycles.co.nz/mm5/graphics/s/surly_track_cog_large.jpg


doesn't need to be flush. Could use a long one and washers. Or get one with a big lip and screw through that?

These solutions may not work, but i'm just throwing ideas round

[mofo]

I'm not as familar with older hubs, so some questions.

Did the original cassette screw on to those threads then the lockring to the outside of the cassette?

If it does, can't the spider be internally spot welded to prevent the freehub from back pedaling. Then mount a single cog to the modified spider. This would mainly require modifying the spider, little damage to your hub, and the hub damage is on a replacable gear in the freehub.

[mDust]

Perhaps I'm wrong, but that's the 'right side' of the wheel right? So if you're pedaling forward, the chain is going to be pulling the cog tighter on the threads. Bicycles don't have reverse, so no major force is going to be 'loosening' it. I would assume if the manufacturer was respectable they wouldn't have threaded it to loosen in the same direction that it's going to be spinning for 99% of its life.
Perhaps I'm missing something else?

[x88x]

I think the problem is that since he's fitting it with a fixed gear (ie, not ratcheting like normal), when he's slowing down, force will be put on the cog in the opposite direction.

[mDust]

I think the problem is that since he's fitting it with a fixed gear (ie, not ratcheting like normal), when he's slowing down, force will be put on the cog in the opposite direction.

Ah, I see now. Well, I vote for the cog-backed-by-that-lockring (or whatever will fit) idea. That should work and would be the easiest to implement.

[Technochicken]

I'm not as familar with older hubs, so some questions.

Did the original cassette screw on to those threads then the lockring to the outside of the cassette?

If it does, can't the spider be internally spot welded to prevent the freehub from back pedaling. Then mount a single cog to the modified spider. This would mainly require modifying the spider, little damage to your hub, and the hub damage is on a replacable gear in the freehub.

This type of hub and ratchet mechanism are called a "freewheel," as opposed to a "cassette" like modern hubs use. The gear cluster is normally only held on by the threads: when you pedal, the cluster is tightened to the threads. No lockring is necessary. If I just welded the ratcheting mechanism in the freewheel together, it would still just unscrew with back force.

Here's an article showing the difference:
http://www.sheldonbrown.com/freewheels.html