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  1. #1
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    Repairing the Wife's Bike- Tourney TY-30 Crankset Question

    First off thank you to the owners and posters here for the website. I spent weeks combing through the wealth of information in the reviews as I shopped for my new/ used bike on Craig's List. I've learned when you don't know go to people who do and educate yourself.

    I'm pretty mechanical (replace most of my own truck parts and turn wrenches on a few race cars when i can) but don't have any real bicycle experience. The second (center) crank gear on my wife's 1999 Diamondback Wildwood is bent and broken. Its decent old bike but she hasn't riden it in a couple years and wants to get it fixed so she can.Rather than dropping it off at the LBS I decided to use the opportunity to fix it myself and learn something. I bought a bicycle tool kit today and pulled the crank and gear off my old off my junked Mongoose to swap the gear set out. I learned lesson #1- the gear set and crank arm are made together and apparently don't come apart.

    I go online and Bikipedia says its hers is a Shimano Ty-30 w/ 170mm crank arms and that appears correct. I shopped a few minutes and several sites say it's unavailable. Amazon doesn't list it.

    So I suppose my questions are 1. Does the gear set come apart from the crank arm and I'm missing something? 2. If it doesn't what is a replacement that will bolt up for a decent old bike that doesn't get much riding so I don't want to spend much on it? Thanks and I look forward to the conversation and will try to contribute around here where I can.

  2. #2
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    Reputation: Aresab's Avatar
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    On very cheap cranks, the chainrings are riveted and when shot, you replace the whole assembly. If I recall, the TY-30 is a square taper (bottom bracket bearings/shaft) so cranks of this type will work, you just need to look at the chainring setup and match that so you don't have to change front derailleur or chain length. Examples are, 24/32/42 or 28/38/48 and refer to the number of teeth per ring. The link below has 24/32/42 cranks that should work fine, they also have other version if you look around the site.
    Shimano Tourney FC-M131 Crankset 170mm - AAWYEAH Bikes and Bicycle Parts

  3. #3
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    Thanks RSabarese for the reply. I have one on the way.

  4. #4
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    I'm just wondering what bent/broken means. On the center chainring there are teeth that will appear to be bent and/or clipped out. They are supposed to be that way in order to enable better front shifting.

  5. #5
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    Quote Originally Posted by epic View Post
    I'm just wondering what bent/broken means. On the center chainring there are teeth that will appear to be bent and/or clipped out. They are supposed to be that way in order to enable better front shifting.

    Its bent for sure. I'm not having any luck uploading the picture to the forum here though. There are four different cracks in the teeth of the gear. Is that normal?

  6. #6
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    nm

    Repairing the Wife's Bike- Tourney TY-30 Crankset Question-img_20130530_100930-copy.jpg



    Is it suposed to look like this? Maybe it is.


    Repairing the Wife's Bike- Tourney TY-30 Crankset Question-img_20130530_100946.jpg

  7. #7
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    Reputation: rockyuphill's Avatar
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    No, that is a dead crankset, it shouldn't look like that.
    I'm a member of NSMBA and IMBA Canada

  8. #8
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    The bend is no good, the cracks are on purpose.

  9. #9
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    On purpose? I know some cheap cranks have problems similar to that right out of the box, but that is wrong. A rock or something must of got it.

  10. #10
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    Quote Originally Posted by epic View Post
    The bend is no good, the cracks are on purpose.
    Quote Originally Posted by aBicycle View Post
    On purpose? I know some cheap cranks have problems similar to that right out of the box, but that is wrong. A rock or something must of got it.
    epic is correct. I've you've ever seen one of the really cheap Shimano cranksets, where the chainrings are are stamped steel, the shifting "ramps" actually end as hangnail like sections of chainring that appear to be broken. Back in my shop days, lots of folks thought that their new bikes had defective parts, but in typical Shimano fashion, they actually shift pretty well when new. In the picture above, rust has caused the paint to lift, which makes it look even worse. As rock mentioned, that crank is toast.

    -D

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