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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    Idea! Replace Parts on Cheap Bike with Shimano Deore etc?

    So my girlfriend has already bought a cheap Chinese bike (with saiguan derailleur, lol) without consulting me, and the changing of gears is just awful, the frame is not aloy, but it is ok. There is a guy who sells old, but good brands bikes, a few years old mostly for a cheap buck. I noticed there are some with deore derailleurs, quality forks, alex rims etc...

    What parts can I replace on the bike?
    1. Can I switch the chinese saiguan with shimano deore(or tourney or whatever) derailleur, at least the rear one?
    2. Can I install disk brakes with the pads on it?
    3. How about the fork, can I replace it?
    4. And most important the shifters, could I switch them with some better ones?

    If everything from the above can be achieved, what would require the most/least work?

    Now I haven't really had experience with bike repair, but I have solid problem solving skills so I'm thinking if it's doable then I'm most likely to accomplish it.

    Any advice on what to focus and what kind of parts to look for in the old bike would be greatly appreciated!

  2. #2
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    Take it apart and build it! It's fun, I'm doing the same thing right now after acquiring a Kona Five-O frame. I'm new at this but I figured taking apart a bike and putting it together is the best way to learn how it works. It will probably be costly, not only for the parts you're purchasing but also for the specialized tools you'll need to accomplish your build.

    What parts can I replace on the bike?
    1. Can I switch the chinese saiguan with shimano deore(or tourney or whatever) derailleur, at least the rear one?
    **Yes, but it has to match the cassette you have on your bike and the shifters, ie., 9 speed cassette w/ 9 speed derailleur and shifters. If you go with SRAM 1:1, it will only work with 1:1 shifters.

    2. Can I install disk brakes with the pads on it?
    You didn't mention if you have V brakes (caliper on the wheel). If so, no you can't - you need a special hub on the wheel than can take disk brake rotors. If not, then yes disk brakes and hydraulic brake rotors are compatible but might need adapters for diff. sizes.

    3. How about the fork, can I replace it?
    Typically yes, but depends on the headset size...my gf bought a walmart bike but the headset was made small so I couldn't replace the fork with the spare I had.

    4. And most important the shifters, could I switch them with some better ones?
    Of course, see #1 above.

    If everything from the above can be achieved, what would require the most/least work?
    Most likely the drivetrain (Derailleurs, shifters, cassette)....but if you decide on hydraulic brakes, learning how to bleed it might take more work.
    Last edited by adonis_abril; 07-18-2012 at 10:36 AM.

  3. #3
    Making due...
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    Regarding installing disc brakes.

    Along with what adonis_abril said, you will need the disc brake mounts on the rear of the frame to have rear discs. If you can replace the fork, then you'll need a fork with disc mounts. And no, v-brake pads will not work with disc brakes, but generally any set of brakes you get will come with pads anyway.

    The frame I'm building up doesn't have disc mounts in the rear so mine will be "mullet" style when I'm done (disc front, v-brake rear). I'd buy a rear disc adapter, but the adapter alone is half the cost of a whole new alloy frame with a rear disc mount.
    1991 Trek 830 Antelope (Commuter/Street/Paved Trail Duty)
    2006 Raleigh Mojave "Lager" Hardtail (XC Budget Build)

  4. #4
    no trees are safe
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    V brakes arent that awful you know... What kind of terrain does she want to ride?

  5. #5
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    Quote Originally Posted by adonis_abril View Post
    Take it apart and build it! It's fun, I'm doing the same thing right now after acquiring a Kona Five-O frame. I'm new at this but I figured taking apart a bike and putting it together is the best way to learn how it works. It will probably be costly, not only for the parts you're purchasing but also for the specialized tools you'll need to accomplish your build.

    What parts can I replace on the bike?
    1. Can I switch the chinese saiguan with shimano deore(or tourney or whatever) derailleur, at least the rear one?
    **Yes, but it has to match the cassette you have on your bike and the shifters, ie., 9 speed cassette w/ 9 speed derailleur and shifters. If you go with SRAM 1:1, it will only work with 1:1 shifters.

    2. Can I install disk brakes with the pads on it?
    You didn't mention if you have V brakes (caliper on the wheel). If so, no you can't - you need a special hub on the wheel than can take disk brake rotors. If not, then yes disk brakes and hydraulic brake rotors are compatible but might need adapters for diff. sizes.

    3. How about the fork, can I replace it?
    Typically yes, but depends on the headset size...my gf bought a walmart bike but the headset was made small so I couldn't replace the fork with the spare I had.

    4. And most important the shifters, could I switch them with some better ones?
    Of course, see #1 above.

    If everything from the above can be achieved, what would require the most/least work?
    Most likely the drivetrain (Derailleurs, shifters, cassette)....but if you decide on hydraulic brakes, learning how to bleed it might take more work.
    Thanks for all the precise answers. Same situation here. She bought a cheap walmart-type brand hardtail bike. If I cannot find some old/crashed bike with healthy shifters/derailleurs, I will be ordering shimano tourney new set and see what I can do. Any pointers on the required tools?

    How about if I only change the rear derailleur/shifters and leave the current cassettes (front and rear) and maybe leave the current front derailleur. Can it work?

    Quote Originally Posted by DuManchu View Post
    Regarding installing disc brakes.

    Along with what adonis_abril said, you will need the disc brake mounts on the rear of the frame to have rear discs. If you can replace the fork, then you'll need a fork with disc mounts. And no, v-brake pads will not work with disc brakes, but generally any set of brakes you get will come with pads anyway.

    The frame I'm building up doesn't have disc mounts in the rear so mine will be "mullet" style when I'm done (disc front, v-brake rear). I'd buy a rear disc adapter, but the adapter alone is half the cost of a whole new alloy frame with a rear disc mount.
    How to check if such rear disc brake mounts exist? Oh, got it, I'll check my bike

    I guess I will be doing "mullet" too, don't believe this cheap frame has any disc mounts, but I'll still check.

    Quote Originally Posted by Millfox View Post
    V brakes arent that awful you know... What kind of terrain does she want to ride?
    Well, this current model is hardtail, but she will be riding it mostly on asphalt, and some off-road, but not too aggressive . I'd like to convince her to ride more off-road with me in future, and that's why it'll be good if her bike is at least capable to hold some light vibrations.

  6. #6
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    Quote Originally Posted by spiritfly View Post
    Thanks for all the precise answers. Same situation here. She bought a cheap walmart-type brand hardtail bike. If I cannot find some old/crashed bike with healthy shifters/derailleurs, I will be ordering shimano tourney new set and see what I can do. Any pointers on the required tools?

    How about if I only change the rear derailleur/shifters and leave the current cassettes (front and rear) and maybe leave the current front derailleur. Can it work?

    You can leave the front derailleur...but again, they have to be compatible because of the chain width...ie, 10 spd chain only work on 10 speed cassette because the spacing between each chainring determines the width of the chain. Check the cassette and count the chainrings, this will tell you the speed and then purchase the derailleur at that speed.

    You will likely need a chain tool to break the chain when changing derailleur unless the chain has a master link that will allow you to detach ends...but you still may need the tool for adjusting chain length depending on the derailleur's cage length(short, medium, long).

    Having tools like THESE are always handy. Here's the chain tool I have. You'll need other tools if you start playing around with the crank.

    Here's my bookmarked/collection of youtube vids that will help you with what you're doing.
    Last edited by adonis_abril; 07-18-2012 at 01:03 PM.

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