The Steering Neck And Other Questions
by Trevor Bradshaw
I have just started planning the building of a bobber frame from your drawing I bought from you, this is my first frame build although I have a professional sheet metal workshop as part of my company, I have some confusion with the steering neck / tube and what fits in it, I am wanting to use springer forks. What head tube would be needed were can I get one to fit the forks I chose, obviously this needs to accommodate the head bearing.
Am I right in thinking most of the kit used is Harley based?
Is the bobber frame based on a standard fork length? Loads of question but as a mechanical engineer I need to know all the ins and outs.
Kind regards, Trevor Bradshaw C.Eng.
Here Is Your Answer
As a fellow mechanical engineer, I completely understand where you are coming from and all of your questions are welcome. The steering tube was designed as a standard tube with an OD of 2 1/8" with a wall thickness of .25". ID is approximately 1.88". You will need to make sure that the bearings that you get will fit this tube diameter correctly. There are a lot of forks and assemblies available all over the internet which you can easily find with a google search. Harley also sells them and you should be able to find the correct part from their dealership or parts counter. The length of the tube is 8". This is pretty standard length for the steering neck on a frame. You can obviously lengthen or shorten this as needed for your custom application. Also keep in mind that if you are going to adjust your rake angle, then it may be necessary to shorten or lengthen the steering neck to give you the right "look". Custom choppers / bobbers are all different and unique and based on your style and what you prefer. Always remember that there is no wrong way to do it as long as it works and it looks aesthetically pleasing to you.
I've attached a photo showing the steering head assembly. It should give you a good idea of how the bearing assembly fits and how the fork should assemble to it. Feel free to email us with additional questions or concerns.