I know derailleur hangers are specific to their frames, and since there are numerous brands with numerous models, I would need to know which one mine is before I can start searching for it, right?

What I know about the bike:

  • Brand: Giant
  • Model: Boulder
  • Frame: Size L, 6061 ALUXX Butted Aluminum

What I need to know:

  • The year this one was brought to market
  • Info on how to search for a derailleur/mech hanger (I fiugre the above will be relevant to that)

I have found this, but how can I be sure it's the right one?

Picture of the bike

Frame size and type

Picture of the derailleur hanger

Any help would be much appreciated!

  • 1
    I've generally found that the best way to find a part is to clean the broken one, and take it to the LBS. For hangers, they probably have a wall chart showing 60+ different sorts of hanger, and you can pick it out of there. Note down what it was, so next time you don't have to guess.
    – Criggie
    Commented Dec 16, 2016 at 19:49

1 Answer 1


It looks like you need this one (Wheels Mfg 21, which they list for Giant Boulders of all years).

If you took the bike to your bike shop, they'd compare the derailleur hanger visually to other ones used by Giant and see there is nothing else like it. Or pull up a chart from Wheels Mfg and look up what bike it is and which ones could fit.

So it looks like the one you have found on eBay is the right one.

  • That answers the biggest part of the question (man, I love this site) Any idea on what year this bike is from?
    – KJdev
    Commented Dec 16, 2016 at 16:38
  • 1
    @DaJF - The Giant Boulder went front suspension in 2004+ in the US (I have a 2003 one). I'd check bikepedia.com's color schemes for the Boulder and Boulder SE to see if you can find something that matches. I'm guessing you're either not in the US or its a Boulder SE (which uses the same derailleur hanger), since the Boulder was steel for all years in the US while the SE went aluminum in 2004 or 2005. But then again, aluminum is spelled correctly, so I don't know.
    – Batman
    Commented Dec 16, 2016 at 16:52
  • Your guess is correct, I'm from Europe (Belgium specifically). So it could be an SE without it being mentioned on the frame? I've compared all color schemes for all Boulders (both regular and SE), and none of them even come close. Does bikepedia.com only have US data, or do I have a special edition or something? Thanks for the effort btw!
    – KJdev
    Commented Dec 16, 2016 at 17:10
  • I think bikepedia is primarily data from the US market -- you could check old Giant Europe (maybe they have a Belgium division?) catalogues. The bikes are sometimes spec'd quite differently in different markets. But my guess is that the only original thing on this bike is the frame, and someone upgraded everything else -- a lot of it looks too high end to be on a Boulder by default.
    – Batman
    Commented Dec 16, 2016 at 17:21

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