Stumbled across this old thread via a Google search on the Envoy. I put a BBSHD on one in 2019... Actually I pretty much just bought the bike for its frame and fork and replaced everything. A proper, capable full on e-cargo bike with a kickass motor is usually well past $4k+ range and I wanted to build something in steps to be gentler on the wallet.
As new products go vs. finding a gem used. I think the Envoy is maybe the best choice as a budget donor you can buy. No need to go apeshit like I did. The bike comes with some pretty decent sized bags to start with. The wheels are pretty strong on their own. I have one of the first USA models and those hubs are solid. I never screwed them up, although I did do custom wheels. I used MTX39s for rims, the DT 350 Hybrid on the back and a Shimano Deore on the front. DT Alpines+brass nipples for spokes. The bike has handled 400+ lb loads no problem, and the wider MTX39's let me put on 2.8" tires which make the ride pillow-soft and up the load capacity of the bike.
The 24T ratchet mech on the 350 Hybrid is not noticeably quicker to engage than the stock 18T, but its solid, and stronger than the 36T you can upgrade to. I do have 36T ratchets on some other builds using that hub and they are nice, and work fine behind my 30a BBSHDs - so far.
Thats a skateboard deck on the back. Extra long means I can throw more stuff up there. The Envoy has all those M5 bosses built in so I put them to use. The risers underneath give me just enough room to use hooks to attach a net without any bother fitting them on.
Also you can fit a front rack on with a little fiddling. Reinforced the wideloaders at 4 points on each side. They are only held on with 4 bolts from factory. Rear rack was tested by Mongoose to carry 90 lbs. Its more now but not sure how much. More than I am willing to try and carry I think.
Made 77L (each) panniers for it. Used cheap but sturdy Rothco parachute bags and they came out almost as big - and just as capable - as the 80L Yuba go-getter bags but a fraction of the cost. Here's a link to how I did it, but if you want to do your own, look for the Bags 2.0 link on this page and see the dowel-and-loop attachment method I did there. Light years better than the hooks I used originally.
There is another post that shows later improvements to these bags. Here is another one that covers a hole I left in this article below. Great Big Bags 2.0 uses a better attachment method. I h…
talesontwowheels.com
There's a series of posts on the various bits of the Envoy build there, too.