Narrow bottom bracket

Earlier I introduced you a narrowed ISIS spindle, but now here is a narrow bottom bracket construction which uses that spindle. While narrowing spindle just about 2 centimeters, I was able to lower my Q-value down to 115mm in my crank setup i introduced some time ago.

Why narrow? The width and the height of the streamliner fairing is mostly determined by the pedal box, which is cranks, BB, and your shoes rotating in a path of your pedal stroke. If we shorten cranks and narrow our BB the pedal box comes smaller and it fits into smaller space and we can make the front section smaller in our fairing.
When narrow is good, it has its own disadvantages. If the pedals are too close to eachothers, ther's very little space for steering, and taking corners has to be with big radius, otherways you may end up rubbing your cranks with your front wheel. So again, it's a balance between the shape and the usableness.

Why ISIS? ISIS-standard is a double edge sword, it's strong, and its weak. I would't blame the priciple itself, the spindle and the overall design is good with 10 tapered grooves, but the weakness lies in old shell standard which defines the space where bearings must fit in. That standard is probably 100 years old bottom bracket shell standard which is too small in diameter to fully cover modern requirements where everything must be strong and reliable. Designs and requirements have changed in these years, but the standard stays, which seems to be very odd in these modern days.
So if you wish to apply a strong thick axel, the drawback comes from the bearings. In order to fit bearings inside the shell, they need to be with very small balls, and smaller they get, weaker they are.

In this design, I did not have to go with the old bottom bracket standards, and I was able to adjust the shell size where ever i wished, thantway I maintained two different advantages: ISIS spindle, which is even thicker than the regular ISIS on it's center, and the free shell size which gives me an opportunity to use any bearing size I need.

There are many other standars for BB out there, the newest is BB30 which is a very good design with thick hollow axel and big bearings and the shell is with no threads, so the design is very simple, but for homebuilder they are problematic. If you wish to use BB30 standard in your design and narrow the spindle, you have a heavy task to modify the cranksetup because BB30 crank comes with the integrated axel and it's not removable, so you actually need to machine your crank, and what if something goes wrong..?

This design is probably the narrowest I can imagine to be usable, probably too narrow for the design..