Folding mid drive conversion options?

Or some kind of low, super narrow 20" BMX frame that can support a long telescoping? Seatpost without cracking, and long handlebars that either fold or have that vertically folding stem to stack it all together along with folding pedals. Seems like this would be the absolute safest solution for a powerful mid drive and mid mounted battery. If you could find something small and narrow enough it could fit in a car too but finding something that supports a really long removed seatpost without cracking and weird handlebars sounds challenging. "Cool down/ warmup extender post" Product Spotlight: Elite Seat Cool Down Seat Post - bmxultra.com
 

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A Mercier nano with bbs02, more room for mounting the battery on the bottom tube, but in no way could disassemble as small as a BMX frame. And bike Friday diamond llama rated to carry 330lb passenger, but unsure on the weight, if bike Friday 's disassembling models are any safer than the folders, or if they even have an iso rating. The terns lack of a front diamond alone gives me some pause already though . Tern byb has some dual tube. Bike Friday might be a good conversion option even if you didn't want a folder, but wanted a 20" bike with gearing and low weight distribution. But the older ones have no front diamond. They also seem to accommodate tall rider frames and ten year frame warranty (onv without a huge freaking motor)
 

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The tern BYB weighs an extra 4 lb vs verge but has dual tubes, but the fold looks less likely to accommodate a mid. Folds much narrower though, no comparison. Sadly only their electric clunker folder cargo has a heavy duty built in rack. It is ISO rated , seems like all the terns are. There wasa recall on the verge x10 and x20 though, make sure if you buy used it has the weld on the bottom of the tube just above the fold. (Folding split tubes are so sus) x10 and x20 have caliper and not disc brakes also
 

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Couple pics of the BYB vs Brompton, brompton vs tern, Brompton vs vello, brompton vs 20 inch bromp. Even with 20 inch wheels the brompton seems to fold much more compact than anything from tern which is a shame because there's probably no way to shoehorn in a mid drive. Maybe a q75 hub motor. It doesn't really seem like the BYB could support a fold, and it looks like it's going "please kill me it hurts to live" next to the Brompton and it's patented fold


Assembling the nob folding bike Fridays takes forever apparently. Not sure yet about moultons
 

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Given the degree you're willing to obsess over this stuff, maybe you won't mind a system that junks your chains and sprockets regularly, and requires constant attention.

But understand that a through-the-gears mid drive will junk your stuff regularly and require constant attention, and a hub motor will not. Also a mid drive has no mechanical redundancy, but a hub drive does.
 
If you go with the Moulton, I have for you the trick barrel quick-disconnect cable connectors for the rear brake and derailleur cables. Makes separating the two sections of the bike much easier.
 
As far as hub motors, The 200w 1,2kg 2.7 lb q75 looks quite good, but I wonder what the absolute highest quality hub motor with best power/weight ratio is and where you start hitting diminishing returns, a 750w nominal 1200w peak hub that fits in a Brompton fold would help a lot, the e Brompton is heavy steel and the 350w stock front hub sucks, maybe rear hub is better, and the 6 lbs battery doesn't last long and mounts high on the front.
 
Probably the stiffest frame out of all the candidates you have posted.
True. But the Moulton has some significant drawbacks. It's a breakdown frame, not a folder. Most of them use a bastard 17" wheel size that I wouldn't want to live with. And it's very spendy for a small wheeled bike.
 
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A lower end Tern Verge with some "250w bafang" and 52tchainring VS The Old Bafang m400 vektron built into the frame (can the m400 support third party batteries?
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the folded vektron looks kinda huge but maybe so is the Tern Verge IRL. Or the 20" brompton conversion for that matter. Hard to find photos of the width of the 20" brompton, maybe theres a reason for that. also looks like you could run wider 16" that would support at least schwalbe big apple, and fat 3 inch wide but theres no puncture protection for that., Brompton Wheel Sizes
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Supposedly brompton forks support a max hub width of 7.4cm wide hubs

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Thinking outside the box, I wonder if you could take some RC motor or other unconventional powerful motor to cram inside the Brompton fork. Or use as a suspended mid drive mount that fits inside the fold somehow. I've seen some hubs used as mid drives mounted above the crank. Using a hub motor as a mid drive // Reddit - Dive into anything

In a Brompton fb group, some were adamant that the heavy 350w front hub was adequate for the 24 +lb steel Brompton uphill, but I was really unimpressed having tested it myself. You might as well find some motor that will just fit the clearance or a custom fork and eat the extra few lbs for real performance. Who knows what going downhill would be like, probably bad. Maybe have a braking Regen system but those are kinda crap
 

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Grintech crystallite saw 20 vs Crystallite nsm, dual hubs?
There's an grintech kit that affixes this to the front wheel. Is it possible to put one in the back as well? Or just in the back? Or maybe lighter crystallite NSM in the back and saw in the front etc. Can you mount batteries to the steel fork? Any other good motors that fit in the brompton 74mm clearance?
There's some odd rear hub motor that requires a whole new fork affixed as well from human cycles, a zegus 250w hub with internal battery, looks kinda dumb
Grintech
saw20 with motor coolant at 72v. Motor is rated as "250/500", I wonder if two "500w" motors would legally put you over the 750w limit. Are grintech rims strong? I heard brompton has stronger alu rims idk.
 
🤔
https://m.you tube.com/watch?v=RGWaEAfiCbA
With smaller wheels, shorter frame, taller seatpost and handlebars, and a removable fork .. the aerospace carbon titanium clown bike of the future... occupy the same space as a folded 16 or 20" Brompton or folded strida (which actually could conceivably accommodate a mid drive but it's just not a very good bike lmao, I think custom plastic 18" wheels?) but safer and mid drive friendly
 

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True. But the Moulton has some significant drawbacks. It's a breakdown frame, not a folder. Most of them use a bastard 17" wheel size that I wouldn't want to live with. And it's very spendy for a small wheeled bike.
Yes agreed but apparently the OP is wanting something that will fit in a car and breakdown frame can do that (one reason I bought a Moulton many years ago). But I hear you on the oddball tire size, never again LOL, one of the reasons I sold it. At that time Dunlop was the sole source mfr and QC was pretty low and price was high. Don't know what the status is now.

Also, the OP strikes me as someone who has to study ALL CONCEIVEABLE options so I wanted to give some data points to help them in their search.
 
Yes agreed but apparently the OP is wanting something that will fit in a car and breakdown frame can do that (one reason I bought a Moulton many years ago). But I hear you on the oddball tire size, never again LOL, one of the reasons I sold it. At that time Dunlop was the sole source mfr and QC was pretty low and price was high. Don't know what the status is now.

Also, the OP strikes me as someone who has to study ALL CONCEIVEABLE options so I wanted to give some data points to help them in their search.
Yeah the breakdown frame is pretty sick but the weird tire size is annoying same with Stridas . Need schwalbe marathon or tannus armor for the mean streets
 
Yes agreed but apparently the OP is wanting something that will fit in a car and breakdown frame can do that (one reason I bought a Moulton many years ago). But I hear you on the oddball tire size, never again LOL, one of the reasons I sold it. At that time Dunlop was the sole source mfr and QC was pretty low and price was high. Don't know what the status is now.

Also, the OP strikes me as someone who has to study ALL CONCEIVEABLE options so I wanted to give some data points to help them in their search.
How did you find the suspension. Also is moulton really inherently "safer" In any way I wonder. I wonder what other methods there are two join two pieces. I had had an idea for a collapsible stringbike with kevlar and someone in Italy actually did it but it fizzled. Now that's built in suspension
 
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i wouldnt actually mess with this but a mid drive conversion for the jackrabbit hub not-quite-abike scooter folder somehow would be amusing. Building something similar as an ultralight non-folder with telescoping
tall seatpost and handlebars, maybe integrated mid drive would be AMAZING though. The jackrabbit weighs 24lb
 
Yeah the breakdown frame is pretty sick but the weird tire size is annoying same with Stridas

Strida bikes use regular 16" (kid bike) tires as far as I know. They also have the structural integrity of an umbrella, and are totally 100% unsuitable for e-assist.
 
How did you find the suspension. Also is moulton really inherently "safer" In any way I wonder. I wonder what other methods there are two join two pieces.
Had my Moulton in the mid-late '80s. Not many suspension bikes around at that time. The suspension is pretty short travel, especially compared to today's offerings, but it did help substantially to smooth the ride, mainly compensating for the ride quality disadvantage of the small tire diameter. The Moulton felt plenty safe as the frame was incredibly structurally rigid, promoting a very stable, connected, confidence-inspiring feeling. The frame geometry also promoted good handling behavior. It loved diving into turns. I would encounter similarly-conditioned and skilled riders on conventional dropbar bikes and the Moulton kept up. Lost out on the ascents (no suspension lockout) but gained back on the descents, likely because of the small wheels lower aerodynamic drag.

The frame connection joints were well engineered and machined, solid, with no chance for misalignment.

Growing tired of the uneconomic and spotty quality sole-source tires (Dunlop), my next bike was a Bridgestone MB-3 (A
Grant Petersen creation?). A fine quality 26 inch early "mountain bike" that used tires with many brands and models to choose from.
 
if the main (only?) criteria is to fit in a car, then i repeat my earlier comment that a folder is not necessary.
A compact frame, 26” wheel, MTB, with QR hubs and a mid drive (Bafang etc) can be quickly dismantled ( seat post , wheels out) and will fit in a mid size sedan trunk, back seat, or small hatch back.
this will give a better frame, better wheels $ tyres, better choice of motors, and a better ride all round than any folder.
 
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