Converting folding bike to mid-drive, is it safe?

Hello all,

these last few weeks I'm banging my head against the wall trying to figure out which bike to get to convert to electric for the easy commuting purposes.
I already have really old MTB with decent equipment but the frame is too big for me so this one has to go.
I also have really cheap steel folding bike, with factory declared weight limit of 265lbs, but I don't feel confident that it is safe enough because there is a play in steering post folding hinge so this one has to go as well.

My candidate number one is Dahon Vybe D7 folding bike because I live in apartment and I need to be able to store it in the office. The problem is weight limit for this bike and most other Dahon folders is 230lbs (105kg) and I alone am 207lbs (94kg). If i add additional 22lbs that tsdz2 + 10ah battery roughly weights I'm already on the limit, without the additional luggage such as backpack.
My thinking was that week point is the frame around hinges and where the seat post is while motor and battery would be located in the middle lower part of the frame and probably rear rack.

I plan on riding to work on bike paths with lot of curbs.

Will this be safe? Can I expect folder to fail due to aluminum fatigue over time?

i converted dahon speed 7 steel frame

ride very overloaded

working okay but wheels too weak

28 spoke rear went to 36 spoke

model you mention is aluminum frame

should survive but make sure rear wheel can handle the weight

strongest folding aluminum xootr swift folder

At your size, maybe one of the 26" wheel folders might ride better but still be storable.



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You have to make your own call on this, hefest. I converted two Downtube aluminum 20" folders with hub motors This company did not spec a weight limit, but it's probably around 105kg too. No problem for my wife at 125, and I feel secure at 195 pounds.

My conversion is a 4.5 pound hubmotor with the controller on a rear rack. A 36V 9AH battery under the seat is 3.5 pounds and good for over 24 miles on flat ground at 15 mph. My drive wheels are Sun-Ringle double wall rims that I laced with double butted 14G/13G spokes to my 36 hole motors. I feel they are quite strong. I believe that neither the hub motor or any gear on my rear racks count against the weight limit, whereas a mid drive would.

I weighed in my Tongsheng TSDZ2 middrive, unmounted, at 8.2 pounds. I haven't run it yet, but should be more than enough. My Q100H hubmotors with a 20A controller spin up to 18/20/22 mph on 36/48/52 volts.

Good bikes are good bikes. It's important to build towards a clear end point/goal
I have a Dahon 8speed steel that is happy with a front hub motor and Downtube Aluminum lX with a small Bafang in the back.
Montague and Dahon Matrix 26" ers
I love foldies and cumbie trikes and find 20"wheels have a personality you get behind and don't fight.
Push them out of their comfort zone and you know it. In it they are happy.
Weight isn't the main issue, but it dictates the shape and speed of their performance envelope
The 26ërs are more "collapsables" than foldies. I am not a big fan of the matrix's hinge, Montague is stout but bulky.
A foldy may need to have the BB support that protects the chainwheel adapted for some mid drives