cvin said:
The quest at least has a throttle but it stupidly sounds like it will not start working until 6mph, so why even have it...
Probably limited like that to comply with some EU rule that doesn't take disabilities or infirmities into account (like most rules).
I specifically have to keep throttles on the trike so I can even get started from 0MPH, when using torque sensor control via the CAv3 (though stupidly oddly if I use cadence-only control I can get started up under many conditions without the throttle, even though the cadence sensor is part of the torque sensor.

). I'd be keeping the throttles anyway for other reasons (primarily backup in case PAS fails or my legs hurt too much to move),
Would like to build one with a bbs02 but to do it with an igh and belt drive is probably going to take months to figure out and i want a bike to ride now
There are some threads for that,some of which are found in this search
https://endless-sphere.com/forums/search.php?keywords=bbs*+igh+belt&terms=all&author=&sc=1&sf=all&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
but Chalo (who does generally know about bicycle stuff

) said this
https://endless-sphere.com/forums/viewtopic.php?f=3&t=100373&p=1469205&hilit=bbs%2A+igh+belt#p1469194
Belt drives only work right when they have static tension on them. Internal gear hubs only work right when they don't have static tension on them. They can't be reconciled. Combining the two beats up one or both components.
Also, belts don't last significantly longer than chains (sometimes not nearly as long) and they're much more expensive to replace.
Though the first problem seems odd since there are a number of prebuilt pedal bikes that use belts on IGHs. I don't know what they did (if anything) to get around it.
In another thread that I forget which one it was, someone that built something like you want found that as long as there was a perfect beltline between front and rear it worked, but otherwise the belt had to be very highly tensioned.
This thread discusses various middrives and belt/igh
https://endless-sphere.com/forums/viewtopic.php?f=28&t=83911&hilit=bbs%2A+igh+belt
Annoying when there is not what you want to buy available....
Pretty much nothing I want to do has commercially-made stuff that just does that; I have to modify or build stuff to do it, or combine several different things never meant to work together, etc. :/
Some things are *sooo* close, but unmodifiable to do what I'm after....