Disc Hub Adapter

Discussion in 'Frame Mounted Engines' started by Bogaurd, May 27, 2008.

  1. Bogaurd

    Bogaurd Member

    I thought I might share this with other Happy Time users.

    If you have a disc hub on the rear wheel of your bike, you can fashion an adapter plate to allow you to bolt your drive sprocket up to the disc hub - which gives you a very stroke mount point, perfectly centered sprocket & distributes the force to both sides of the wheel evenly.

    The adapter plate sits something like this:

    The green in the picture is the drive sprocket, the pink is the adapter plate. The white represents some sort of spacer.

    My adapter plate was made out of 3mm steel, it turned out like this:

    The hole in the centre of the rear drive sprocket was bored out to 53mm to allow clearance over the disc hub. The adapter plate is just a 120mm disc with a 33mm hole bored in the centre, and the appropriate hole patterns for your disc hub & sprocket drilled in it.

    Attached Files:

    Last edited by a moderator: May 27, 2008

  2. turkeyssr

    turkeyssr Guest

    This is also relevant for Titan users. I would certainly have consider this option versus the custom sproket assuming the price point is lower for this version. I think this version would also have helped me in left side clearance issues.

    How did you make this? What was the cost?

    Thanks! - John
    Last edited by a moderator: May 28, 2008
  3. Bogaurd

    Bogaurd Member

    Hi John,
    I drew up some designs for this, and had it made at an engineering firm nearby.

    The cost was 30 Australian dollars including the drilling of all holes & enlarging of the center hole in the drive sprocket.

  4. MasterLink

    MasterLink Member


    could you ship that ? to the usa ?
  5. ocscully

    ocscully Member


    You can pick up essenitally the same thing at Your Local Bike Shop or any dealer that sells Bicycle disc Brake Rotors. Member AzBill used a 6in disc brake rotor and mounted the sprocket to it. You can add spacers to get what ever chain line you need. See his photos over in the Photo gallery the Thread is called My Jag

  6. Bogaurd

    Bogaurd Member

    Indeed! :smile:

    The only reason I didn't go this way is that the frame I have was not designed for use with disc brakes, and there is insufficient clearance for a disc rotor in the rear stays (I tried!)

    Either way, you'll probably need to increase the size of the center hole of your sprocket - mine came with a ~30mm hole, I had it bored out to around 55mm to clear the disc hub.
  7. MasterLink

    MasterLink Member

    ok thanks man i will have a look
  8. loquin

    loquin Active Member

    BTW. Located this hole pattern for disk brake mounts.

    The standard today is the 44 mm center-to-center spacing with M5 tapped holes.

    Occasionally, you may also come across one with a 48 mm center-to-center spacing, with 4 mm countersunk holes.

    Attached Files: