Hey! I built these Custom Beach Cruisers back in 2008! Had great memories riding up and down the coast Huntington Beach Calif. We are now in our 60's thinking of adding eBike Conversion Kits, 3 of the bikes are
"Phat frames" one custom made by me. They are like 7' 5" long 7 speed 24" wheels disc brakes. Any suggestions? I really like the Bafang kits
A couple of thoughts. Chainline? Should be no problem with the length from chainring to rear hub! Looks like my Long John Yuba cargo bike!
You mentioned the bikes have 7 speed drive trains. Looking at them I'm assuming they are internal geared hubs? Johhny N.O. did a great video on his own 5 speed igh build. Check it out @ https://youtu.be/VRoucNtcfDQ Watch till end.
My experience with an 8 speed Nexus IGH was great till I trusted it to a local bike shop who must've shifted under load when I brought it in for an unrelated issue. It grinded so badly on my way home I switched back to a freewheel and the Nexus hasn't returned to my Surly Troll bike. I had just 500 miles on it. You really, really need to be careful about not shifting under load with an IGH, as I'm sure you know. Thus a "gear shift sensor" is a must--not negotiable-- for a bafang build w/ an IGH . I also was using a Tong Sheng TSDZ2 which is a torque sensing motor (without a gear shift sensor) and was gentle enough --As Long As You Know How To Shift.
--I'd be hesitant to loan those bikes you're envisioning to IGH novices once you've got a motor on them!! Finally, I would strongly suggest booking a session via zoom, or whatever platform you can finangle w/Johnny Nerd Out. A 10 minute session as far as I know is still quite affordable, and might save you some serious money further down the line. And you'd be talking to a star.
By the way, cool looking bikes!!
Stylin'! Did you do the paint, too?
As for the motor install, (w/o a closer look at the BB), I don't see a problem. The battery might need a custom enclosure but these beauties deserve it.