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Replacing a 7-speed gear cluster - what is it?

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Replacing a 7-speed gear cluster - what is it?

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Old 01-21-08, 02:43 PM
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Katzenjammer
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Replacing a 7-speed gear cluster - what is it?

I have a mid-range off-road bike with a 3x7 setup (1995 model, but I'd be surprized if any of the parts involved are original) The teeth on the smallest gears are quite worn, as I discovered after having the chain start skipping under load. So I imagine it's time to replace them. But I've no idea what it is, apart from something made by Shimano. Is there any way to tell whether it's a freewheel or a cassette or a pneumothorax without taking it apart?
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Old 01-21-08, 03:20 PM
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Post a pic of it here. Wheel out of the frame and shot straight on the hub end, or pretty close to it.
And model number off of it may be enough, if you can find it.
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Old 01-21-08, 04:30 PM
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Originally Posted by Katzenjammer View Post
I have a mid-range off-road bike with a 3x7 setup (1995 model, but I'd be surprized if any of the parts involved are original) The teeth on the smallest gears are quite worn, as I discovered after having the chain start skipping under load. So I imagine it's time to replace them. But I've no idea what it is, apart from something made by Shimano. Is there any way to tell whether it's a freewheel or a cassette or a pneumothorax without taking it apart?
Yes, I have made a specific Web page for exactly this question: http://sheldonbrown.com/free-k7

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Old 01-24-08, 08:22 AM
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Thanks, Sheldon. Unfortunately, mine doesn't look completely like any of the photos you posted. I'd provide a photo of mine as Bob suggested, but my camera is momentarily hors de service.

Mine one looks least unlike the one on the right (cassette with lockring). Mine says "hyperglide-c" on it (it looks like a 'c' anyhow), and it shows a US Patent of 4889521 if that helps. I also see what looks to be a spliny edge as per your photo, but otherwise the resemblance is more in the fact that it looks even less like any of the others.
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Old 01-24-08, 09:06 AM
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Well, methinks from Sheldon's pretty, hi-res photos that you probably do in fact have the hyperglide with cassette. I only say this because, upon maximizing Sheldon's picture, it says Hyperglide and has the same patent number on it.
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Old 01-24-08, 09:15 AM
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Originally Posted by Katzenjammer View Post
Thanks, Sheldon. Unfortunately, mine doesn't look completely like any of the photos you posted. I'd provide a photo of mine as Bob suggested, but my camera is momentarily hors de service.

Mine one looks least unlike the one on the right (cassette with lockring). Mine says "hyperglide-c" on it (it looks like a 'c' anyhow), and it shows a US Patent of 4889521 if that helps. I also see what looks to be a spliny edge as per your photo, but otherwise the resemblance is more in the fact that it looks even less like any of the others.
My mid-90's 3X7 Mountain Bike has a cassette, of course that doesn't help you too much.

Any chance you could take your wheel into a bike shop and ask?

I can't remember if later shimano freewheels and lock rings take the same removal tool or not. As long as you can return the tool if it's the wrong one, it might be worth just trying. If it's a cassette, the whole thing will just spin backwards without coming off, - you'll need a chain whip.

If it's a freewheel, it won't turn at all without a whole lot of leverage.
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