1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
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  1. #1
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    Changing my rear Cassette

    I recently dug out my old college bike (2000 Giant Boulder SE) and started riding it to work. It's about ten miles, and I recently upgraded to clipless pedals, which I've been happy with. That said, there are times going downhill when I feel I could go faster if I had a different gear ratio (or if I pedaled crazy-fast.) Since I'm already approaching my limit of financial expenditure, I purchased an inexpensive new cassette (Shimano CS-HG30-7) on Ebay. Looking at my bike however, it appears that my hub is larger than the smallest gear, and the existing nut appears to thread from the inside instead of the outside.

    I'm planning to head over to a bike shop this evening and see if it's possible to use this cassette on my bike, or practical to convert my hub if it won't fit as is. That said, It's still several hours until I leave work, and I'd like to understand what the possibilities are so I don't sound uninformed when I get there.

    What do people here think (If I've provided enough information.) Anyone care to help educate the ignorant?

    (attached is a picture of the new cassette, I can probably take a picture of my hub as well if that would help.)
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  2. #2
    g3h6o3
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    The cassette on your boulder was probably a 8 speed. You bought a 7 speed so there's gonna be some place left on your freewheel. Use a spacer and it hould be alright.

    That said, I think both your cassettes will have an 11T small cog so swaping them will be useless.
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  3. #3
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    Do you have any idea how many teeth you have on the biggest and smallest cog? Depending on what tooth numbers you have in back, it might be that you instead need to change the size of your chainrings up front.

  4. #4
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    Quote Originally Posted by PissedOffCil
    The cassette on your boulder was probably a 8 speed. You bought a 7 speed so there's gonna be some place left on your freewheel. Use a spacer and it hould be alright.

    That said, I think both your cassettes will have an 11T small cog so swaping them will be useless.

    The old cassette is a 7 speed, that much I'm sure of. It's a 21 speed bike with three on the front crank.

    Answering the other question, the old cassette is 28-14 teeth.

  5. #5
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    Quote Originally Posted by Call_me_Al
    Do you have any idea how many teeth you have on the biggest and smallest cog? Depending on what tooth numbers you have in back, it might be that you instead need to change the size of your chainrings up front.
    The front ones are 28/38/48, the rear are 14-28

  6. #6
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    your old hub has a thread on freewheel most likely. that cassette you bought will not fit on. please brief yourself on freewheels and cassettes here http://www.sheldonbrown.com/free-k7.html

  7. #7
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    Quote Originally Posted by reptilezs
    your old hub has a thread on freewheel most likely. that cassette you bought will not fit on. please brief yourself on freewheels and cassettes here http://www.sheldonbrown.com/free-k7.html
    Thanks, that page is very informative. Mine looks almost exactly like the one here: http://www.sheldonbrown.com/free-k7/...wl-shimano.jpg
    So it looks like your guess is correct. Is it possible to convert or replace the hub, or am I better off replacing the wheel? Any idea what any of these options might cost? (keeping in mind that I'm just looking for basic parts at this point, nothing fancy.)

  8. #8
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    Ok, think I'm figuring this out now

    Ok, with some more reading, this is making more sense to me. It sounds like I'll need to change the hub out. Before I spend more money, does this hub look like it will take my 11 tooth cassette?

    I'll take it to a bike shop to have it laced, are there any other things I should be aware or concerned of before I buy? I realize that this is a cheap part and probably not the best quality, but as long as it will get me to work and back and not be any worse than the stock part I have now, I'll be happy.

    Edit: It looks like the forum took my ebay link out. The part I was looking at was a shimano rm-40
    Last edited by KeithKris; 06-30-2008 at 12:06 PM.

  9. #9
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    Wow, honestly I wouldn't bother paying to have that relatively low-end hub laced to your 8-year-old wheels. Rebuilding a crappy set of wheels isn't worth the money. Just pick up a fresh pair of wheels.

    Here are some Rhynolites laced to XT hubs (much nicer than the rm-40's) for $150 AND they're disc compatable, so if you decide to upgrade to disc brakes later on, you've already taken care of the wheel upgrade.

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