This is a remix of the original design by Phoenix125 over on Thingiverse, except now compatible with road bikes instead of mountain bikes.  This little thing works great if you are on a stationary and want your handlebars to be able to turn.  The skateboard bearing mechanism is very well done.  I also made a center plug for it as well, as I never liked the idea of all my tire's weight being on just the edges of it.  Now there can be pretty even pressure all the way through this mount and hopefully no damage to your tire/tube.  Despite not having bearings on the center part, it still rotates very well.

Print one each of these, then go to the original and print the parts you need there, all according to the original instructions.  For reference, my road bike (specialized tarmac) uses the 7 degree base.