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  1. #1
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    hypothetically speaking

    Could you take an old 7,8,9 speed cog dremel off the rest of the gears and use that? I mean you might have to cut some off the left and right side then use a spacer to make it line up correctly. But wouldn't it work?

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    Quote Originally Posted by gigatech
    Could you take an old 7,8,9 speed cog dremel off the rest of the gears and use that? I mean you might have to cut some off the left and right side then use a spacer to make it line up correctly. But wouldn't it work?
    You don't need to use a dremmel. Cheaper cassettes (ones with individual rings stuck together, as opposed to ones with a spider) can usually be taken apart with an allen wrench. They're an alternating series of cogs and spacers. You can use any of the cogs, and then use the spacers to get it in the right place. You will need the spacers from more than one casette though.

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    Quote Originally Posted by Hardtails Are Better
    Cheaper cassettes (ones with individual rings stuck together, as opposed to ones with a spider) can usually be taken apart with an allen wrench.
    It's also a good idea to flip the cog so it's on backwards to help keep the chain from trying to shift off. You can make it fit by using your dremel and grinding just a wee bit off one side of the widest spline on the cog. If this doesn't make sense to you it probably will when you try to mount it backwards.

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    Quote Originally Posted by rocky rode
    It's also a good idea to flip the cog so it's on backwards to help keep the chain from trying to shift off. You can make it fit by using your dremel and grinding just a wee bit off one side of the widest spline on the cog. If this doesn't make sense to you it probably will when you try to mount it backwards.
    I don't see why that would help. All it would do is make the chain try to shift off to the opposite side. It also seems that the profile of the teeth would lead to more chain slippage with the cog on backwards.

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    Quote Originally Posted by Hardtails Are Better
    I don't see why that would help. All it would do is make the chain try to shift off to the opposite side. It also seems that the profile of the teeth would lead to more chain slippage with the cog on backwards.
    The chain will be pulling on the opposite side of the cog teeth thereby making the ramps ineffective. I've had no issues with slippage with the reversed cog, I believe this is a fairly common modification if you are using a cassette cog for SS. It has eliminated chain derailment for me anyway.

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    Quote Originally Posted by gigatech
    Could you take an old 7,8,9 speed cog dremel off the rest of the gears and use that? I mean you might have to cut some off the left and right side then use a spacer to make it line up correctly. But wouldn't it work?
    It should be mentioned that aside from the better solution of taking the cassette apart, that there are quite a few different cassette types which may disassemble differently. Check out Sheldon's page on casettes to see what you need to take apart a particular cassette:

    http://sheldonbrown.com/k7.html
    http://www.sheldonbrown.com/freewheels.html

    Note that cassettes with cogs that are "pinned" together fall apart easily by hammering out the pins.
    Last edited by pahearn; 02-26-2007 at 10:48 AM.
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    i'd been looking at this very thing for a while - I have a 7 speed cog and it looks a bit like this one - I cant figure how to get the individual cogs off - they look like they're screwed on or something??? I can get the freewheel off with my chain whip but didn't know if it was possible to dismantle it further. any suggestions?
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    Quote Originally Posted by Pudgerboy
    i'd been looking at this very thing for a while - I have a 7 speed cog and it looks a bit like this one - I cant figure how to get the individual cogs off - they look like they're screwed on or something??? I can get the freewheel off with my chain whip but didn't know if it was possible to dismantle it further. any suggestions?
    All casettes look "a bit like that one", so check out the links I posted above and match your cassette up to see what you're dealing with. The smallest cog is likely right-hand threaded (right tight left loose). Remove the small cog and the rest will slide out (possibily riveted together, which you can punch out). To remove the cog you either need two chainwhips, or a workbench vise to clamp the small cog into while you twist the whole wheel IN THE PROPER DIRECTION. You get awesome leverage this way. Just always triple check that you're turning things in the proper direction.

    http://sheldonbrown.com/k7.html
    http://www.sheldonbrown.com/freewheels.html
    Last edited by pahearn; 02-26-2007 at 11:00 AM.
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    Heh heh yes that was rather vague of me, my apologies. Thanks for the input, i'll give it a try. So once the small cog has been removed the others should theoretically be a bunch of cogs and spacers?

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    Quote Originally Posted by Pudgerboy
    Heh heh yes that was rather vague of me, my apologies. Thanks for the input, i'll give it a try. So once the small cog has been removed the others should theoretically be a bunch of cogs and spacers?


    Yeah -- and like someone said you'll obviously need more spacers than you can yield in just taking that one cassette apart, so either take apart another or use some PVC piping in combination with some of the spacers you yeild to get a good chainline.

    With the cassette you have you should be able to see from the back-end of it (looking at the back of the largest cog) whether or not they're all riveted together (you'll see 3-4 rivets). if they are, then once you remove the small cog, the whole thing will slide out, and then use a hammer and punch (or crappy phillips screwdriver, whatever) to tap them out. They come out super easy. But that's the easy part, those small cogs can be a ***** to remove, good luck...
    pete

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    cheers feller! I have a small phillips ready for the pin punching, and a sledgehammer ready for when i fail to get the small cog off.

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    Quote Originally Posted by Pudgerboy
    i'd been looking at this very thing for a while - I have a 7 speed cog and it looks a bit like this one - I cant figure how to get the individual cogs off - they look like they're screwed on or something??? I can get the freewheel off with my chain whip but didn't know if it was possible to dismantle it further. any suggestions?
    That's a freewheel. If you actually have a casette, which it sounds like you do, that'll work. A freewheel, like the one pictured, won't. You can often take the cogs off, but they don't fit on your hub once you've done so.

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    Hi Hardtails,

    Thanks for your reply. with regards to my old wheel, it's a 5 speed freewheel, not a cassette made up of individual cogs.its off a real old steel MTb that i use as a local runabout.There is no splined hub on the wheel to put cogs onto, only a thread to attach the freewheel to. Its an old bike but it rides real nice.

    I came to the conclusion when i was looking at it at the time that I couldn't see how it could be streamlined into one cog on this freewheel body and I had reserved myself that i'd just use my MTB wheelset from my other bike when i upgraded that.

    I will check and get a photo so that i can be a bit less vague about the whole thing.

    My other question thats been niggling me about freewheel hubs is this - Don't you have less ability to tweak your chainline with a freewheel? i know you can put spacers on external BBs (in 2.5mm increments), and swap to the midlle ring on the crank etc but you dont have the whole range of spacing options that you do on a splined freehub. I guess its just an aesthetic thing again?

    Thanks!

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    if you have a freewheel you just unscrew the whole works and thread a singlespeed freewheel on.

    but then you get into probably having to adjust the chainline...

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    Hi max-a-mill,

    I thought that the chainline would have been out far too much to correct - as the freewheel hub on the wheel is for a five speed, it's not as wide as a dedicated singlespeed wheel.

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    Quote Originally Posted by Pudgerboy
    Hi max-a-mill,

    I thought that the chainline would have been out far too much to correct - as the freewheel hub on the wheel is for a five speed, it's not as wide as a dedicated singlespeed wheel.
    yeah at that point you could respace the hub to bring it over to the right line. then you'd need to redish your wheel to bring it back to center... all in all a lot of work.

    you ever try to just run the chain to the cog it fits on and run it superghetto syle??? i am betting you 5spd cassette has no shifty ramps so just line it up to a cog with good chainline, get the chain aprropriately short, tension her up, and hope the gear stays put and works for your purposes...

  17. #17
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    That's exactly what i'm doing Max. I had no idea i was superghetto style!

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    ok - this is the freewheel i've got. Here's a crazy idea - Couldnt you use a holesaw or something and drill off the larger cogs from the back, leaving the body and single 14T cog on the end? would it lose strength that way? although you can see that the cogs look like they are threaded on the body somehow so it might be possible to undo this and add spacers, keeping the hub spacing and thus removing the need to center and re-dish the wheel? I could be way off here, but its been something that has been bothering me for a while.....
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    OK, here's what I'd do. Run it SS on that freewheel, and just ignore the 4 cogs you aren't using. It'll look a little silly, but it'll work just fine, and won't hardly be any effort to put together at all.

  20. #20
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    Sure thing - its what i've been running on it for six months anyway! Its just that I CAN'T...STOP...TINKERING

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