dpbcb

I would like to build my first bike frame, and I am about to start my research. I had some questions, and I am hoping this forum could help me out. The bike will be a hybrid bike with disc brakes, belt drive and alfine 11. I would like to choose the parts and design to keep things as simple as possible. I am willing to make some sacrifices in order to get the difficulty level to low as possible.

Bottom bracket: Any recommendations? I would prefer to use a bottom bracket that is threadless, and does not require any recesses or lips. In other words, I want to choose a bottom bracket so that the shell is simply an aluminum tube. I cannot seem to find any simple documentation on a bottom bracket, and the associated width of shell, inner diameter, and outer diameter. Does anyone have that info for a Shimano BB 86? Any other contenders, and if so, what are the associated shell length, ID and OD?

Disc brakes: I would like the front and back rotors to be the same size, and preferably small as possible. Can I put 140 mm rotors in the front and back? If not, can I use 160 mm? I prefer dual action mechanical disc brakes. Any recommendations? What are the pros and cons for post vs ISO mounts? Do ISO mounts accommodate 140 or 160? The disc brake choice will also affect what type of sliding dropouts I choose, whether it be ISO compliant or post mount.


Headset: I wanted to use a Chris King Headset. I want to use a threadless headset, so that the tube is as simple as possible. I need to know the length, which I am assuming can be variable, and then I also need the inner and outer diameter. I couldn't tell if the headsets require some type of recessed lip, but I am definitely trying to avoid that.

Sliding dropouts: Since the bike will be Alfine 11 with belt drive, I was planning on using sliding dropouts. It seems that the hub is only compatible with 135 mm spacing, which I assume is the distance between the posts. So I assume I need to incorporate the width of the sliding drop out insert as well into the frame build, so that when inserted, the space is 135 mm.

unterhausen

if you don't have facing/reaming/tapping required to build a frame, it's not all that hard to find a bike shop that does. The simplest bb shell to deal with by far is a threaded shell. The smooth bore shells have to have tight tolerances post-weld and for most of us that means an expensive reamer. Similarly, most bike shops can ream and face a headtube. That takes care of the headset/head tube interface. There is no lip inside the head tube that is part of the interface with the headset.

There are post mount adapters for ISO brake mounts, so ISO might be your best bet. From what I can tell, all brakes that ship nowadays are post mount with ISO adapters. The only post mount sliders that I know of are the Paragon 140mm through axle version, so you are stuck with ISO in the back AFAIK.

135mm is how much space you need for an axle between whatever parts make up the dropouts.

My suggestion is to look at what other beginners have done and see what they used. You will quickly get a pretty good idea of what is easiest

dpbcb

Thank you so much. I am definitely going with ISO disc brakes in the front and rear.

In regards to the bottom bracket shell, my friend will be helping me with the build. He owns an oil and gas machine shop, complete with cnc machines and lathes. I am not worried about the tolerances, because of the equipment and his employees can give me a hand here or there. That being said, what BB should I use for a smooth bore application, and what would be the width, ID, and OD?

On the headset, I plan on having just a plane cylindrical tube as well. If I go with a threadless Chris King headset (1 and 1/8), then I assum the inner diameter needs to be 1 1/8, and the outside diameter does not matter? No lips or recesses needed?

Thanks again.