I bought a Frankenbike off Craigslist.


It's a Specialized Rockhopper of unknown year, converted to a commuter, with shocks up front and V-brakes.

I love this weird little bike and want to put a Copenhagen wheel on it when they come out, to make it into the ultimate commuter frankenbike.

To install the wheel I'll need to know whether I'm dealing with a freewheel or a cassette. How can I find out without taking the bike apart or knowing the year it was built?

  • 1
    And why do you need to know if it is freewheel or cassette to install the wheel? The wheel installs the same and works the same.
    – paparazzo
    Commented Jun 13, 2014 at 0:43
  • Kibbee's advice of posting a close up for confirmation is a good one, but guessing the age of the bike based on the components and Specialized graphics I'm 90% sure you have a cassette.
    – vlieg
    Commented Jun 13, 2014 at 3:42
  • 1
    Yeah, A Specialized bike of that age would most likely have a cassette, but as the OP mentioned, it's a "frankenbike" which means many parts have been changed out. So it's probably worth verifying.
    – Kibbee
    Commented Jun 13, 2014 at 12:43
  • @Blam I read that if installing on a freewheel machine I would need to adjust the derailleurs (which for me would mean getting help instead of doing it myself).
    – hairboat
    Commented Jun 13, 2014 at 14:55
  • What age would you guys say the frame is, based on the graphics etc?
    – hairboat
    Commented Jun 13, 2014 at 14:56

1 Answer 1


If you take the back wheel off you should be able to examine the freewheel/cassette to determine which it is. Here is a picture of some common types. If yours doesn't look like one in the picture, post a close up and I'm sure someone here can identify it.

enter image description here

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