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Options for fixing / replacing cassette
#1
Just bought.a Schwinn road bike and found d that when I shift into 12th.gear my chain wants to jump off. Looks like my cassette is very worn as no amount.of adjustments can get chain to stop jumping. The guy who sold it to me says I have impossible to find sun tour cassette. I do not know what to even look for as far as replacing these gears. Can anyone help this new ?? Pics Included
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#2
A few things:
- By "jumping" do you mean that the chain jumps over the teeth on the cogs and the pedals slip under pressure? (And not that the chain is jumping off to the outside of the cog set - this is a derailleur adjustment issue) If so, then yes, you likely need new cogs and a chain.

- Suntour did make cassettes and they are hard to find, though I think you can still get them online. But the cassette is pretty rare. Suntour stuff is usually a freewheel. I can't tell for sure, but from the shape of the teeth, I suspect you have a freewheel. The easiest way to be sure is to see if the cogs have two notches cut out on the outside like in this picture: http://farm4.static.flickr.com/3200/2694859898_f45d0e9262.jpg (Note that I mean the two longer slots on either side of the axle, not the two round holes a little farther out.) If it has these two notches, you have a freewheel and can replace it with any 6 (or maybe 7) speed freewheel.

- If it is a cassette (and you can't find a replacement at a reasonable price), you would have to get a new hub or a new wheel. A new wheel is likely cheaper once you include the cost of rebuilding a new hub into the old rim. At that point, you'd have a few options of which way to go. But figure out what you have first.
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#3
This should help. I see Shimano via II on.the rear hub..I think it safe to disregard what the seller told me as everything seems to be.shimano. I think he made up a lie about the parts being impossible to find to cover the fact that he should have fixed this issue or at least informed me about it.
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#4
Yup, freewheel. If it is skipping under load, you should just need a new freewheel (and should probably replace the chain at the same time though it looks fairly new.) It looks like you have friction shifting so you can use any brand freewheel. You can probably go up to 7 speed if you want (there should be enough room to fit a 7, though can't guarantee) or stick with a 6.

You can buy the tool to remove the old freewheel, or just stop in to a shop to have them pop it off for you (5 minute job). You don't need any tools to install new freewheel.
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#5
Thanks for the help !! Yes the chain skips under load. It is fine until load is put on it. So basically the seller was lying when he told me I have a sun tour setup which is impossible to find and that he would have had to replace the entire wheel to fix ??

I am going to remove the back wheel when I get home and take some more pics , because I could swear I saw the splines vs having the two indents on the inside of the cog.. if this was the case then I would have a frrehub cassette , right.???

Totally new to this , bear with me on the dumb questions
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#6
It occurs to me that what you might have is an early 6 speed Shimano "uniglide" cassette. If so, you're probably back to having to replace the hub/wheel. The slight twist on the teeth is typical of Shimano stuff, not Suntour.

http://sheldonbrown.com/k7.html
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#7
Here is a better pic. I do not.see the two notches. Are we certain.this is a freewheel ??
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#8
Looks like a shimano uniglide cassette to me. They are available on ebay, though not cheap.
Note that the slipping could be due either to worn cogs or to a worn interior ratchet in the freehub. In which case, new cogs won't help at all. Just warning you...

Seller was right, just had the wrong brand.
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#9
Teeth count is 13-29 if that helps. Also I can clearly see "Shimano products " stamped on the freewheel or cassette in question
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#10
(01-21-2013, 09:52 PM)jwpowell19 Wrote:  ... stamped on the freewheel or cassette in question
My initial thought was wrong. It is a cassette. You could try replacing the cogs, though I can't say for sure that it would solve the skipping.
I'd get a new wheel or hub, but that's me.
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#11
It is slipping off the sprocket , I can see the.chain jump if I look down as I am pedaling. Derailer is properly adjusted. This only happens in 12th gear. So essentially , assuming.I can.do work.myself that doesn't require proprietary tools , what is my most affordable way to get my 6th and 12th gear working again ??
So would this work ??

http://pages.ebay.com/link/?nav=item.view&id=271134785049

How much am.I.looking.at to replace the entire.hub ?
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#12
(01-21-2013, 10:01 PM)jwpowell19 Wrote:  So would this work ??


How much am.I.looking.at to replace the entire.hub ?

Nope. If it is the outermost cog that is slipping, you need a new cog that has threads on the inside, not the splined inner ones.

This is the cheapest thing I see: http://www.ebay.com/itm/Shimano-Uniglide-Cassette-7-speed-13-24-/170978109751?pt=Cycling_Parts_Accessories&hash=item27cf16e937, but it is used. On ebay at least, don't see any individual cogs of the right type.

Price on a new wheel and gear set could range from $70 to hundreds depending on what you want to do. (6 speed, 7 speed, higher, freewheel, modern cassette, rim type, wheel quality, etc.) Generally it is cheaper to buy pre-built wheel than to have a new hub laced into an existing wheel. Handbuilt wheels tend to be more durable, depending on the quality of the parts of course.
(01-21-2013, 10:01 PM)jwpowell19 Wrote:  assuming.I can.do work.myself that doesn't require proprietary tools
Removing the cassette requires two "chain whips", or a shop could do it for you quick. No tools required to install a new one.
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#13
Looking at the cassette teeth, they look ok not too worn out. So I do not think your problem is in the cassette. (BTW Freewheel usually has a wider hub at the gear end). I see lots of grease so looks like there was some service there. If the chain is jumping and not staying on the largest inner gear I'd suspect misalignment in chain line and the derailer. If you are trying to shift from the large front chain ring to the large rear gear that's too much cross over, you should not shift much more than half gears and than go to the inner front gear and continue shifting. Does the chain jump when you use the smaller front chainring with the large rear gear?
AS per PO do not be so ready to jump on him, the bike looks ok, perhaps he just did not know what he had, that's not unusual with most owners.
Never Give Up!!!
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#14
OOps I meant to say most freehub cassetes have a thicker hub on gear end.

As per your link you show the smallest rear cog, If thats where the chain jumps off does it do it when you use the large front chain ring too? The chain look worn have you cleaned and lubed it , does it bend easy , no stiff links?
Your gear does not look all that different from the new one you show on ebay. Worn cogs get wide valleys and pointed teeth.

So I think your problem is likely in the adjustment or sticky derailleur.

From the downtube shifters your bike looks 80's here is a link to Schwinn info.

http://www.trfindley.com/flschwinn_1981_1990/index.html
Never Give Up!!!
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