On Thursday, May 14, 2020 at 5:11:10 PM UTC+1, wrote:
My KUMA Montrose is either PF30 or BSA (bottom bracket shell is removable). I recently got a PF30 BB on my KUMA Grava... then I started thinking... (not on purpose).

Heh-heh. Should be streng verboten.

I like single speeds, then if I install an EBB, I can make the KUMA Montrose a true single speed bike. If I want to make it a fixed gear bike with 700x38, all I need to do is flip the wheel, and replace the brake rotor with a cog. I did that before with a Trek Sawyer and worked perfectly fine.

Anyone using an EBB on their PF30 enabled bicycle?

Though I've ridden only hub gear bikes for twenty years, I have zero personal experience of eccentric bottom brackets. But, because it is a civilised forum with a lot of Rohloff expertise, even though I have a German bike with sliding axle hangers designed by Herr Rohloff himself, I'm on the forum of a British manufacturer who fits EBB to hub gear bikes, so I get to read quite a bit about EBB from people who do high mileages a long way from civilisation -- it's a forum for mainly touring bikes. One thing that has struck me about the discussion there is that an EBB, generally made of aluminium, gets dented so badly by the holding screws over a period of time that the dents form channels and then the EBB rotates at the most awkard times. So I consider the EBB a poor solution, in fact a consumable which has to be replaced every so often. A better soolution is a bottom bracket shell with two facing flat lips on the outside, drilled for two bolts that clamp it around the EBB, but that has to be integrated into the design from the drawing board forward unless you're a genius brazer or welder. If the 30 in the component you mention is for 30mm, you should establish first of all that you can get both an EBB to fit the BB shell, and a BB to fit the EBB; these things come in a limited range of diameters.

Andre Jute
There's design and then there's German design