Saale

Really interesting looking construction, so you basically stretched a Y-frame MTB and added a rack directly to the frame with the free swinging rear wheel underneath? Looks like both wheels remained 26", correct?

I understand your concern on a mechanical level, and you would have to tune the suspension for a full load instead of an empty one, leaving it very stiff when empty, but if a well tuned full suspension makes a loaded cargo bike more controllable then surely it's worth a consideration, costs notwithstanding.

That's kind of what I'm thinking. Well balanced when loaded, stiff when empty, but potentially preferable to stiff all the time.

By that logic a motorcycle tire is the suspension, but I wouldn't trust a motorcycle or even a scooter with welded springs with my life.

I mean, I'm aware that there's a great difference in weight between an empty cargo bike and a loaded cargo bike, and that you can't possibly tune the suspension for all scenarios, but by my understanding of physics and engineering a suspension adjusted for load would leave an empty cargo bike almost like a rigid bike, but improve loaded ride comfort and ride safety, wouldn't it? I'd allow reality to prove me wrong if I ever come across an occasion, but I'd be shocked because in my head the suspension pretty much makes sense.