Design a Freewheel Crankset for Direct Mount Crankests

[ScooterMan101]

Good Timely Find Luke,

Here is what I understand from Sram .

30 mm spindles are better for Strength and Light weight

24 mm spindles are better for durability ( regarding the BB bearings themself's , not the spindle or crank arms)

But How many people who ride e-bikes ride in the rain and mud where the 24mm outer bearing system is a little better ?
It looks like this new product from them is mainly to benefit the wet weather MTB riders.


I find the last paragraph informative ...
" SRAM will continue to support GXP and 30-millimeter-spindle cranks, so don't expect to be forced into this new concept before you're ready. And if you are ready but you've got a non-boost frame, you won't be forced out of it either. SRAM boasts that DUB is "backward and forward compatible." But forward compatibility is hard to predict. Look far enough forward, and maybe our bikes won't even have cranks. "

And I really like the last sentence ...
"But forward compatibility is hard to predict. Look far enough forward, and maybe our bikes won't even have cranks. "

Perhaps the Author has ridden an electric bike with a throttle ?

So funny just after reading this, I saw this:

https://www.bikemag.com/gear/components/drivetrain/sram-introduces-dub-crank-bottom-bracket-technology/

Going to 28.99mm from 30mm, because you know... lol

 

[PaulD]

The Cinch adaptor is a bit more complicated than anticipated, but possible. It needs to be two pieces - one that threads into where the lockring goes (pink), and one that holds the freewheel and engages the cinch spline (green).
Maaaybe we could get away without using the lock ring threads, and rely on the bearing pre-load force to keep the adaptor engaged with the spline (second picture).
With a 151mm spindle intended for an 83mm bb shell, and a 17mm thick freewheel, it just barely fits. So, no room to sandwich motor mounting plates under the BB cups, unless we accept a wider q-factor of a spindle for 100mm bb fatbike.

 

[PaulD]

3D printed a prototype of the version without lock ring to check fitment with the spline. Dare me to try to ride it around the block?