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Old 01-19-07, 09:47 AM   #1
zoeglassjd
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Cassette Disassembly

I need a bit of help with an old Shimano cassette disassembly for a SS mtb conversion.

It is of a pre-90's panasonic MTB. It does not seem to have a lock ring- I think it is just the small cog is a lock ring... I have tried using a chain whip to crank this smallest cog off, but it won't budge.

I have checked Sheldon Brown's site on conversions and need a bit more. Is there any tricks to this or is it just uber-tight as it has not been taken apart before... I am tempted to start wailing on it, but I want to use spacers and one of the cogs on the assembly to make the bike.

I have tried a couple of combos of cassette tool/chain whip- I do not have the shimano spline tool- although it seems like this is not necessary for this application/

anyhelp?

I have done some searches to find this on here to no avail- but if you know a thread I would welcome a nod in that direction

thanks
zgjd
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Old 01-19-07, 10:17 AM   #2
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Originally Posted by zoeglassjd
I need a bit of help with an old Shimano cassette disassembly for a SS mtb conversion.

It is of a pre-90's panasonic MTB. It does not seem to have a lock ring- I think it is just the small cog is a lock ring... I have tried using a chain whip to crank this smallest cog off, but it won't budge.

I have checked Sheldon Brown's site on conversions and need a bit more. Is there any tricks to this or is it just uber-tight as it has not been taken apart before... I am tempted to start wailing on it, but I want to use spacers and one of the cogs on the assembly to make the bike.

I have tried a couple of combos of cassette tool/chain whip- I do not have the shimano spline tool- although it seems like this is not necessary for this application/
If it's a Uniglide cassette, (no splined lockring) the smallest sprocket is, indeed what holds it all together. You need _two_ chain whips to remove a Uniglide cassette. One goes on the smallest sprocket to unscrew it, the other goes on one of the other sprockets to keep the cassette from spinning backwards.

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Old 01-19-07, 10:23 AM   #3
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Simple solution. This cassette is even easier to remove than hyperglide. You are correct that the smallest cog is the lockring. You have a Uniglide - Shimano's earlier generation cassette. What you must have is a 2nd chain whip. While turning the first chain whip counterclockwise on the lockring cog, the thing would just freewheel on the freehub body. What you need is a second chain whip oriented in the opposite direction that you can grab onto to stop this backward rotation. Get the 2 chainwhips oriented correctly with the handles about 90 degrees opposed from each other and squeeze til the lockring cog starts to unthread itself. Remove the chainwhips, turn the cog the rest of the way by hand and you're done!
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Old 01-19-07, 11:28 AM   #4
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thanks guys! although I was hoping i was going to do this without a second chain whip...

and naturally- thanks sheldon for all your great resources!!
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Old 01-19-07, 01:40 PM   #5
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ok, sounds simple enough. I've been cranking on this thing with two chain whips like mad and I can't get the outside cog to budge... any suggestions on getting it to come off? i think it is just really tight from age and abuse
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Old 01-19-07, 01:47 PM   #6
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I've did a rough and ready removal by screwing the big cog to a benchtop which was bolted to the wall, a screw in every second depression and then reefing on the lockcog with a chain whip.
Perhaps an application of penetrating oil and some time for it to soak in will help.
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Old 01-19-07, 04:39 PM   #7
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Originally Posted by zoeglassjd
ok, sounds simple enough. I've been cranking on this thing with two chain whips like mad and I can't get the outside cog to budge... any suggestions on getting it to come off? i think it is just really tight from age and abuse
Remember what I said about orienting the chainwhips so that they are opposite of each other and the handles are like 90 degrees from each other? Well there's a reason for that and it has to to with mechanical advantage. Its a little hard to explain but you're cranking counterclockwise on the lockring cog and holding the other one stationary on one of the bigger cogs, its flipped with the chain going the opposite direction. you want to be able to squeeze the handles of both chain whips simultaneously, all you need to do is to get that lockring cog to turn counterclockwise. I know this may not sound clear but once you've successfully done it, even the tightest locking cog will be no match for you. What kind of chain whips are you using?
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Old 01-19-07, 04:56 PM   #8
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masi-

one is a sette and the other is an offbrand from the lbs- but looks just like sette (and park for that matter)- if I am picturing what you are saying: the handles of the two whips should cross over one another and form an X sortof (like at the bottom of this Park page: http://www.parktool.com/repair/readhowto.asp?id=48) ... I wasn't doing that. I simply had them each on and at a ninety. I will try this tomorrow.

thanks for your help.
zgjd
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