How do you know what fits?

Discussion in 'General Bike Discussion' started by Keith, Aug 14, 2009.

  1. Keith

    Keith New Member

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    I see so often people talking about swapping out hubs, forks, etc. etc. into their bike ala modifying it from stock.

    How do you know what fits for what bikes made by different companies? Do you just read forums on others that have done it, is it all based on the size, or how does one know what fits what.
     
  2. glens2422

    glens2422 New Member

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    For many components its the diamenter that determines if parts are interchangeable. Most newer bikes are pretty compatible, however campy parts won't interchange with most shimano parts but Sram will interchange with Shimano. Forks and headsets are based on diameter, mostly 1 1/8". Bottom brackets will vary in size also. Is there something specific you are trying accomplish ? If not then the best way to find out these types of things is to become friendly with the mechanic at your local bike shop (LBS).
     

  3. tajcrews

    tajcrews New Member

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    I think glens2422 sums it pretty well. Your LBS can give you a lot advice or you can always come here and ask as i am pretty sure we can definitely help you out. Is there something specific you are inquiring about?
     
  4. hophead

    hophead New Member Tavern Member

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    I get info from books, forums, friends, websites like the Park Tools & Harris Cyclery, my LBS etc.

    What fits what really depends on what specific area of the bike your working on. Many things are standard for instance, most modern mtn bikes use a 1-1/8" threadless headset so to swap out a fork, all that really maters is that the fork has a 1-1/8" steerer and the steerer must be at least as long as the fork it is replacing. If it's longer, you can cut it down or use spacers to make up the difference. You also have to make sure that you are using the same type of brakes, disc or rim. If it's disc, you also have to make sure that you have the proper mounting hardware for the fork. Some forks use the standard post mount and others have a tab mount.

    Mtn bike handlebars used to be 25.4mm (diameter at stem), but now many mtn bikes have gone to 31.8mm. So to swap out a handlebar that's the only dimension that you have to match to your stem.

    Hubs get a little more complicated. To replace a hub you must match the hole count with the rim. Get the correct spoke length and decide what type of spoke to use (straight gauge, double butted, tripple butted, black, silver, etc...) Brass or alloy nipples? Disc or rim brakes? Front or rear? Size? If it's a rear, what type of gears, cassette or singlespeed?

    So, some upgrades can be simple and others can be rather complicate--Just like Jeeps!
    With one exception. You can't use Sram rear shifters with Shimano rear derailleurs and vice versa.
     
  5. bantam700

    bantam700 New Member

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    Are shimano front derailleurs and sram shifters compatible?
     
  6. hophead

    hophead New Member Tavern Member

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    Yup.
     
  7. Industry_Hack

    Industry_Hack Total noob (& forum admin) Admin Staff Tavern Member

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    New bikes, old bikes, road bikes, mountain bikes. Within each class and price range, the parts are all fairly interchangeable, but there's not much in the way of standards. For instance, seat tube diameters and thickness vary so widely from steel and titanium frames to OS aluminum frames, that there are multiple sizes of front derailleurs and a sizeable variety of seatposts.

    As someone mentioned, headsets are pretty constant, with the 1-1/8" threadless replacing the 1" threaded, but look for the 1.5" to become more popular. There's a huge advantage in stiffness with a negligble weight penalty.

    If you have a specific component in mind, I'm sure folks will chime in.