Wooden Frame Build

[Daniel_Y]

Here is some good information:

How to choose BB shell width?

I love BB standards (sarcasm) I wrote up some standards a while back: Are you building a steel or titanium bike? The first question to ask is, do you need a T47bb? [DSC02939] For a steel bike, these are the reasons to use T47: If you want to run the cable housings internally through the BB more space for 30mm spindles (this is mostly for fancy machined cranksets) If you find yourself using 38mm and larger downtubes (mountain bikes). Having a larger BB shell gives a better surface to wel…

Lets talk road/gravel standards:

BSA

BSA BB shells for road/gravel bikes are 68mm with external bearings. Carbon bikes needed more space on the BB, so they invented the BB86 (86mm wide pressfit) bottom bracket which moves the bearings inside the shell.

BB86

PF30

PF30 is larger diameter compared to BB86 and narrower 68mm) because it has external bearings

T47

T47 came along, and you have two options, external (68mm wide) and internal bearings (85.5mm wide). The industry also decided to make T47 85.5mm wide to make the wrench splines thicker:

I think the industry converged on internal bearings (85.5mm) for road and gravel bikes.

TLDR:

I think T47x85.5 will give you the most space to build your chainstays and downtube around. Paragon makes an aluminium BB shell specifically for bonding, but its only for 68mm wide: BB4039 - Aluminum T47 Bottom Bracket Shell 1.937" OD x 68 mm Wide x M47 x 1 Thread

From an engineering standpoint, I think BB86 would be the best standard for your bike. The BB shell is wide and only 1.5in diameter. This gives you the most flexibility to build around the BB shell. However, no one believes in this standard except for Canyon!