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I recently bought a women's Schwinn "Clear Creek" 18-speed mountain bike at a yard sale. The rear derailleur is broken, and the rear sprockets are rusty and don't turn easily against the wheel. I think I can replace the broken derailleur, but what should I do about the rear sprockets? I'm not so worried about the visible rust as I am about the fact the there is such resistance when I turn them freely against the wheel. Should I remove them and grease them somehow? Are there bearings in them that can be replaced?

  • All you can do is take it apart and see what's broken. – Daniel R Hicks Oct 24 '15 at 22:50
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    My guess is that an 18 speed mountain bike uses a freewheel, so if the problem is in the freewheel unit, you'd get a whole new freewheel. It is a BSO, so don't stick too much money in it. If its too much friction in the wheel itself, you can try repacking the bearings and or adjusting the hub. – Batman Oct 24 '15 at 23:19
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    Are you handy with tools? Are you prepared to get a bit dirty and invest some time? I think you need to get the rear wheel off, and remove the freewheel or cassette to see what its like. Worst case, you now own a parts donor bike. – Criggie Oct 25 '15 at 3:44
  • Note that one very likely cause of this is trash caught between the cluster and the hub. – Daniel R Hicks Oct 25 '15 at 11:18
  • Thanks, all, for your comments. I'm still learning the lingo, though. I just learned that when I said "sprockets" I really meant "cassette." Still don't know what BSO means... – Baodad Oct 26 '15 at 4:06
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Rusty sprockets aren't typically going to be an issue. As long as the teeth aren't too worn in, then the cogs themselves will be fine. However, if the cogset (likely a freewheel) itself is having difficulty rotating, it's likely the grease in the ratcheting mechanism has seized up, or the pawls are broken or faulty.

The internals of the freewheel might "wake up" if you try taking it for a spin, but it also might just be busted.

While servicing freewheels can be difficult, it is possible and the late Sheldon Brown could explain the process better than I could. The information is a little dated though, and might not be applicable to the part you have on hand.

Freewheels are a fairly inexpensive part, though there are some tools you'll need to remove the old one to put a new one on. If you don't have them and aren't willing to invest, your local bike shop would be able to mount it.

The busted derailleur is something you can probably handle, since that's usually just a couple of bolts to mount it. Watch out for the derailleur hanger though, since that's often damaged before, or with, the derailleur itself.

Something to keep in mind is that if your cogs are rusted, your cables might not be in great shape either. Look them over and pull on the brake levers. If they're unresponsive, stiff, or slow to retract, they'll likely need replacement. Gear cables will cause trouble with shifting.

Good luck and happy wrenching!

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