I'm down a rabbit hole


1 µW
Jun 16, 2019
I think I want to build my own DIY bike. For the price/quality it doesn't seem like you can come close any other way. But, I want to do it kinda cheap like(1-1.2k usd) and I'm also in love with the folding bike concept.

The basics of what I'm looking for are a solid frame and an upgrade path. I'm kind of a fatty at the 240lb mark so frame is important.

I don't care about being a speed demon but going 25mph is nice through the residential zones. I'll probably be doing short 2 mile stints but having the ability to go 20 miles once in awhile is a good mark.

Sooo down the rabbit hole I've found https://www.rakuten.com/shop/cyclin...4e2wBfMhb0eh_-1wTxwboWq2tIBCnwjRoCMigQAvD_BwE a HASA folding bike which seems like it has a solid frame with disc brake mounts. I do want disc brakes because I think stopping is just as important as going and also want to upgrade to hydraulic in future. It looks like Dahon is the default but I'm not rollin in that type of money. The only other brand I came across from HASA was Camp in that price range?

I've also found http://recycles-ebike.com/48v-tsdz-...hainwheelwith-thumb-throttlecutoff-brake.html TSDZ2 for the mid drive. It looks like there is a site or 2 to get these pretty cheap. It just seems like a good option for cheap. I'm ok with a bafang at a good price too but it seems these kits average cheaper.

The battery seems to be the biggest hole. It looks like you can buy some cheap stuff from china all day but it's a gamble and a half. It kinda looks like you get what you pay for in this realm. So is EM3ev the best option here? I think I need a 48v at least 10ah pack. Looking for quality for cheap. I think I'm pretty much going to strap the battery to the rear rack.

The future upgrades I'm looking to are hydraulic brakes, sturmey archer 3 speed and fattier tires.

Seems like the deeper I go the more questions pop up. In the end I just want a cheapish folding E-bike. Not a speed demon but something reliable. I'm always function over form so tell me if I'm way off in what I've somewhat narrowed down to now.

I'm open to any suggestions and any trusted site links.

Thanks in advance.
25 mph is very speed demon territory on a folding bike with a heavy rider. Even with a 52T front gear on the TSDZ2, you don't have the gearing to spin the pedals at that speed, so it will be all throttle. At 240 pounds, you're right at the weight limit claim for most folders. The 20" wheels are not forgiving either. You will probably want to go up to 2" wide tires for more cushioning. I don't know that mechanical disks are much better than a good V-brake, but they make wider tires easier to fit.

Some of the folding steerer tubes seem pretty strong. Some look pretty flimsy. Consider that a regular bike has a quill or threadless stem clamp with a short and solid steerer. Folders put something that is 16-24" long that has a hinge in it. Cheap ones are going to flex. I don't worry about the frame hinge failing, but think that a cheapo steerer could snap if one pulled back on the bars hard to jump a curb. Don't jump curbs.

I am in the rabbit club with two light weight folder conversions. I used Downtube folders. My wife uses an 8FS, with full suspension, but she is only 130 pounds and it's a nice ride for her. Mine is a Nova. I am 200 pounds. Both use small hub motors. On 36V, they only pull 500W max and top out around 18-20 mph. I have gone 48V and seen 22 mph on mine. Where do you put a big battery on a folder? It's hard. I run small battery packs like a 36V 10S3P (30 cells) and pairing up two 36B 10S2P (20 cells each). They're good for 30+ miles at pedal assisted 14 mph. And we rarely fold them. The first time I folded mine, I found I didn't put enough slack in my wires. Pulled out all the connectors.
A folding bike isn't a good option for riding. It's not designed for that. It's designed to fit in places a proper bike can't. If you're not below average height and weight, a folding bike is not usually even a safe option. If you don't believe me that they suck, please go to a well-stocked bike shop and ride a folding bike back-to-back with normal bikes in your size. Wishful thinking will not be enough to maintain the illusion that folding bikes are satisfactory. They are something you use because you're in a situation where you can't use a real bike.

At your weight, I think the Swift Folder is the only small-wheeled folding bike I'd trust to hold up. It's still handicapped compared to a normal bike. Remember that normal bikes are normal because they've been vetted and refined for over 150 years, and what's traditional is actually what's been found to work best over that time.

Disc brakes aren't a good match for small wheels. They are designed to work with larger wheels, and they become too abrupt and grabby when used with small wheels. Combined with the short wheelbase and awkward frame angles of a folding bike, this is a recipe for unnecessary crashing. The included disc brakes on the Rakuten bike you linked to are almost certainly weak and crappy, which under the circumstances might be considered a safety feature.

Brake rotors and hydraulic hoses are much more likely to be damaged when they're on small-wheeled bikes and those that fold. Rim brakes, drum brakes, and coaster brakes tend to develop minor, easily fixable problems. Discs and hydraulics tend to develop problems that totally disable the brakes (like a fluid leak or a pulled-out hose) or make the bike unridable (like a badly bent rotor).

If you're only comfortable spending sub-$400 on a bike for conversion, it had better be a real bike (not a folder) and ideally it should be a used bike. Cheap new bikes under $400 are doing all they can to cope with ordinary human power and speeds. Cheap folding bikes under $400 aren't even capable of dealing with human power for very many miles. If you want a new and cheap bike, suitable for electric conversion, look for a sturdy 26" wheeled bike with one-speed gearing and V-brakes. That's the most robust and effective setup you can get for cheap.

Here's an example of a bike you can get for $300 new, that won't crap out quickly when you add a heavyweight rider plus electric motor power. If you're tall, even the tallest size available won't be a good fit, though:

If you want to "upgrade" to an internal gear hub later, don't start with a bike that has vertical dropout slots and a derailleur. It's difficult to reconcile such a bike with the need to take up slack in a single speed chain, while leaving room for the gearhub's clickbox.

TSDZ2 is far from proven, and it looks like a much better bet for lightweight riders and modest power outputs than for luxury-sized American adults and USA legal maximum e-bike power levels. It will eat up a disproportionate amount of your modest budget compared to a cheap hub motor. It's better, I think, to get a cheap and simple hub motor kit and spend more of the budget on a better bike and battery. If you must have a mid drive, the Bafang BBS02 looks less problematic (though comparably expensive).
I like mine so far but it's ridden very much as a slow speed cruiser under it's weight limits.
Even at 25Kph the ride gets a bit sketchy..

For touring I was interested in these:

Maybe start with a gooder frame + (cheaper) hub motor :)
For 2 mile average, a folding electric scooter with suspension would make much more sense for you. The folding electric bike is a very niche product compared to those two, it basicly combines the drawbacks of both but very few advantages.
I'm curious why folding is so important. Urban use? carry in a sedan trunk?

Your body size would be much better off with a sturdy steel frame beach cruiser. Those make excellent ebikes, and cost is moderate for the better ones. Cheap as hell for the schwinns and huffies. This would leave more money for better battery.

Not saying there are no really good folding bikes, but the best ones will not be cheap.
Even better would be to have a folding car that you can carry in the luggage of your full-sized e-bike.
glockjs said:
Seems like the deeper I go the more questions pop up. In the end I just want a cheapish folding E-bike. Not a speed demon but something reliable. I'm always function over form so tell me if I'm way off in what I've somewhat narrowed down to now.

I'm open to any suggestions and any trusted site links.

Thanks in advance.
I thought about doing something like that, before scrapping the idea. A few considerations for you to think about.
1. If you're upgrade path include fatter tires, then you need to make the decision up front, on what frames with support that.
2. Based on what you want, you may want to consider a hub motor, and a hub motor in a small wheel can have plenty of torque to propel a heavier load.
3. Finding places to hang all of the ebike stuff on a small folding frame will be a challenge, so that's something to consider in the frame design.

Here's where I ended up, before scrapping the idea. The starting bike is an ebike, with generous space where the existing battery is, to upgrade to something much larger. The sealed controller box built into the frame might have enough room for upgrading to something like a Phaserunner. If not, the box can be used for wiring connections. The bike already has a cheap suspension fork, and frame and wheels setup up for discs, and fat tires. There are a few of these types of folders on Amazon:


My thinking was to ride the bike as is for a while, then decide on my upgrade path, which would involve replacing the controller and batter, and getting a beefier rear hub motor laced to the same 20" fat tire rim. I think the cheap discs would be adequate for the lower speeds I planned to ride at. I may still build something like that since it would be easy to load into the extended cab of my truck (to keep is secure, since the narrow plan for the bike would be for camping trips, and specifically camping at the track for bike and car races). The big battery wouldn't really be as much for range, per se, but to last over 3 to 4 days of putting around trackside or the camp site without having to charge.
Welcome to the forum.

Lets start with the good. EM3ev is a great company to deal with. you're right about the 48v 10Ah battery, if you keep speeds in the 15mph range. Building your own bike is more rewarding, and you can build a better bike for your money. 1.2K is a good working budget, and you should be able to reach your goals with ease.

Folders are useful. I have one and it certainly fills a need that none of my other ebikes do. That said, it's easily the least comfortable, least fun to ride ebike I have.

Most folders are rated to take between 210 and 220lbs. Cheap ones rarely publish weight limits, but don't expect them to be more. You're likely going to be exceeding the weight limit of that bike. remember, you need to account for another 20 to 30 pounds worth of motor, controller, battery, racks, mounts, etc.

25mph on a folder is not an experience I want to repeat often. With a short wheelbase, a frame design that leaves it too flexible, and weight poorly distributed over the wheels, the bike will try to dump you off at every opportunity. 15mph is about the max reasonable speed on a cheap folder. Even at 15mph, stopping is sketchy. the wheelbase is too short and the weight is too high, so any panic braking will try to flip the bike over the front wheel.

As Chalo mentioned, that's not a good frame for a 3 speed, or for any IGH. You need horizontal dropouts so that you can properly tension the chain. the vertical dropouts of that frame won't work. If you choose that bike, leave it a 7 speed.

The motor you picked is known for being much weaker and problematic compared to the Bafang BBS02. Saving money by getting something that will break isn't saving money. If you don't have many steep hills, you might consider a 500w geared hub motor. that will knock hundreds off your build cost, and increase your reliability.

Disk brakes are nice on large wheels and fast bikes. they are actually often worse on slow bikes and small wheels. Consider that your wheel IS a disk. Disks on folders are prone to getting bent, so limit how useful a folding bike frame can be. Hydraulic brakes add more complications with leaks, kinked fluid lines during folding, air bubbles getting in the line when the reservoir is inverted, etc. All things being equal, I'd rather have a rim brake on a folder, and so I do.

It's not all bad news. Folding ebikes have their place, and are much better than not being able to carry your ebike with you. I really do enjoy taking mine on trips. But if you don't need it to fold, a conventional bike would be much much better for building an ebike.

That's one big bag :)

My bike has a limit at 105kg, it's very similar to the mariner/ e-joe, but some of these bikes iv'e seen the seller list at 120kg. Wonder what, if any, testing goes into such bikes, with so many new designs. Even 105kg's seems a reasonable limit. It's actually the stem that concerns me most, I was mulling over the thought a folding fork -brace-like thing, like Jones susp. that could lock on to the fork tree and at least keep the whole thing in place..

Mine gives access to the bus network which is otherwise a no go.. it would be possible to tour the state's better rides on a tour between buses.

I actually like riding it, slowish.. turns on a dime, it takes me back to BMX days.. and handles well enough so as I start to/need to remember the hinges..
Nice. There's some good info. Thanks guys.

I guess the big take away's so far are that discs aren't too good of an idea and being a beefy boy I'm gonna have to find a better frame and prob go with the bafang. I was looking at the mid drives due to the folding concept and not having to deal with chucking the controller somewhere.

After looking a little deeper it looks like EuroMini Forte might work with a 300lb capacity. Or if I want to go faster and have disc brakes the Montague Paratrooper might be a nice choice but would put me over budget :/ The change frame looks nice but it doesn't look like it would work with a mid drive and also would be even more over budget.

Thanks again. Looks like I got some decisions to ponder.
Like this one? https://www.amazon.com/EuroMini-ZiZZO-Heavy-Duty-300-Limit/dp/B07L3BFNJL

I'd suggest that unless it's a local seller prepared to back up that 300lb claim it may not be a worthwhile selling point..?
But, for your own piece of mind, look at similar frames and their rating.

Even this one, with a steel frame is listed at 220: https://www.ebay.com.au/itm/Fortis-Urban-Traveller-20-Folding-Bike/171908227920?epid=503057335&hash=item2806876350:g:G~sAAOSwfvlbw2eW
(for some reason folding bikes and folding ebikes and even some non folders seem to be getting cheaper here than they are in the US)

Another point is that they all seem to offer Shimano Tourney if derailers, which so far is fine in mine, but I suspect it's just to use the brand name, everything else is the cheapest of cheap crap.

I swapped the no name mech brakes for TRP dual pull, iv'e done this on my other ebikes, even swapping the tektros. From a newby perspective (who went from calipers to discs) they work very well. The first set were indeed grabby and the pads were squealy but now they just seem like my other discs. The need for a light hand on the front, on the little bike, became 2nd nature in a few days.
Ozzzz said:

Yeah that's the one. The more I look into it I think that company is on the up and up. Somebody somewhere made a good point that the material doesn't matter as much as the design. Looking a little bit close at that bike it looks like they use their same design but made the frame a tiny bit thicker and added more support to the buckle. From what I've read it seems most bikes will put a safe number for weight in case they have to cover their behind.

I keep going back and forth on what to do. A front hub would shave off a few bucks but doesn't seem worth it in the end.

I think no matter what I'm going to be spending 500-600 bucks on a trustworthy battery shipped so that part of it is kind of locked in.

It seems like I can get a cheapish BBS02 from most china direct sources for 400-450(looking at PSWPOWER atm)

It seems I've narrowed down the frame to that zizzo forte or just go ahead and spend the extra on a paratrooper pro. But if I buy the montague it seems like it deserves a BBSHD and a 52v battery which flexes the cost closer to $2300 with the bike. I think I'm pricing the forte at $1350 without including unexpected cost with tools and knick knacks.

This all started when I bought an EB-5. I road it a couple of times but then sold it to my nephew because he needed wheels for getting to work. But the short time I spent on it has me hooked! I understand just how awesome this space is. I have half a mind just to buy another one but throwing $420 on a cheap e bike vs putting the money towards something that's more long term doesn't seem like a contest. The only other bike I've seen that looks anything interesting is the Lectric xp. But at that price something somewhere has to give and there are no reviews besides gifted ones.

I just want to build something that will last for some years. Seems like the more I learn and dive....the more I go back and forth :(
I went with a cheap setup but can see room to upgrade just about everything lol... it's a very similar frame to some of these:


With in mind to rebuild it/ (them, I bought 2)
So.. already added a 17ah battery, brakes (mine came with a susp fork/front disc, not listed in the add), grips, saddle, pedals and will probably replace the cranks and add a 52t chainring. Thudbuster make a long suspension dahon post that may work well for heavier dudes and i'd expect most frames this style would take a 4" tread. I'd just 'upgrade' mine to a bafang hub + display, then again.. a torque sensor would be nice :)

I like the in-frame battery design and (if size matters) a massive coupling.. which made the decision easier. The batteries are a bit hard to source but you can get them (and cases..) tbh i'm not sure i'd expect really long term from these frames but a few years cruzin for sure.

The Montague has had a long history now, I guess it would be a better distance bike and better all round on trails & make more use of a mid-drive? but like your guy on y-tube there's something about the little bike. Fun for shorter distance, easy cruising, just what he seems to be using it for.
Yes, I get it that a folder packs better. But I did not ask about that. Why does he need it to fold?

Just about any car can have a lightweight hitch attached, and then a swagman rack will carry a heavy bike. Mine carries this easy. With its 35 pound motor wheel.( including tire and slime)6-1-2015  Schwinn Cruiser with 52 t crank.JPG

Just wondering why the fold is the one thing he absolutely needs.

Small wheels have big advantages for hub motors, but a more adult size BMX bike fits in any hatchback easy, especially if you put a QR front wheel on it.
Agreed. Would be good to know why the folding is needed. That said, for two mile trips, I wonder why you even need/want an electric? A standard bicycle works pretty darned well all by its lonesome for such short trips. Do you have big hills to climb?

And the hills question makes me wonder why you seem to think that a mid-drive is an upgrade. If you have hills and are heavy, then the mid-drive makes a lot of sense. But otherwise - for the 2 mile trips and even your 20 mile occasional long ride case a direct drive hub motor would be a good, simple, economical choice.

Right now, I think a Monague folder looks like a good choice. Those are common enough that you can probably find a used on on Craigslist if you live in or near a major city. Just be sure to check for knock-offs. There are a lot of fakes out there. And they might even be OK bikes. But with your concern about strength, I'd make sure it is genuine.

Seems like the more I learn and dive....the more I go back and forth :(

Ha ha ha! That's the pitfall of today's "overchoice" marketplace. Too many options leaves you feeling overwhelmed and depressed! It's like standing in front of the dressing aisle at the grocery store, how the f********** are you supposed to pick one and feel good about it?

For bike selection I wanted to toss a suggestion in the ring: a Giant Expressway or Expressway 2, used. This is a great little folding bike I use as my regular bike. I'm over 270lbs and I've ridden it for many years without a single issue outside regular maintenance. It's got a very solid frame and rides nicely. The fork is chromoly too, so you should be safe putting a low-wattage hub motor in it (I would NOT put more than 500w into a folder... they aren't made for those kind of stresses at all).
You don't get disc brakes with it, but if you're only looking for something to do short jaunts on, and fun rides, V-brakes will suffice. You may have to do brake maintenance more often, but once you get decent at it the task is not much of a challenge.

For motor, if you're not wanting to dig into installing a bafang (I don't know that this is any more difficult than a hub motor), then a small diameter geared hubmotor up front might be your best option. You could also do a rear one. HillTopper makes an excellent little kit that doesn't even have a throttle, just a push-button. There are several good geared motors on the market... and this would be excellent if you have hills to deal with too.

A kit like this might do nicely: https://www.amazon.com/AW-Electric-Bicycle-Front-Wheel/dp/B01C6QZ2US/ref=sr_1_57_sspa?keywords=20%22+ebike+kit+-fat&qid=1560870873&s=gateway&sr=8-57-spons&psc=1

Anyways, I hope you find the right fit. I wouldn't worry about all the "why do you need a folding bike" questions, it's a waste of time to answer them all. There's lots of reasons someone might want one, and I don't feel it's helpful to go visiting the intentions of someone asking for help. If he or she has their heart set on a folding bike, just accept it and help said person build the safest, funnest ebike their budget will allow. It's a hobby, not a courtroom.
dequinox said:
If he or she has their heart set on a folding bike, just accept it and help said person build the safest, funnest ebike their budget will allow.


Here's how you make a folding bike safer for electric assist use: Get a steel-framed one. Weld up all the places that fold. Add a downtube to the frame, and weld it in place. Be sure to ride it somewhere that doesn't have potholes, grates, speed bumps, or stepped edges.

Or simply leave it folded in the trunk of your car, because that's what it's for.
At 270lbs, there is no way you would have got me on one of those rickety looking folding bike frames.
At 190lbs, i got confident and tried about a dozen of them. Still rickety. Bought one i thought would be solid.... didn't feel like something i'd want to ride at over 20mph. The steering, due to the way you are positioned, is extremely twitchy on all the folder bikes i rode.

Test ride before you buy!
I agree with Chalo.

I, too had visions of building a nice folding E-bike to take on trips, etc. I bought a nice used Dahon speed a few years ago and had it shipped to me as there were none for sale locally (this kept me from test riding it). I am 6'4", 195 pounds, and riding that bike was about the worst bike riding experience I have ever had. I swear that the bike was so far underneath me that it would have flipped over frontwards if I had put the brakes even semi-hard. It also felt very twitchy and unsafe. I put it up for sale without even riding it more than two miles and never rode it again. I have also found that a "non-folded" bike actually takes up less room in a wagon or minivan than a folding bike does because a standard bike is long and thin when put against the side of the vehicle interior. With the front wheel removed and the handle bars then turned to be in line with the bike frame, my normal bike doesn't take up much space at all. If you need to fit the bike in a vehicle trunk, then a folder makes more sense. You might think about an adult BMX bike or a cruiser as suggested earlier. I have built a mid drive bike and a hub motor bike, and if you don't have large hills to ride up, a hub motor bike is more relaxing to ride on the street as you don't have to keep shifting to keep the mid drive motor in it's "happy" RPM range. I am VERY happy with my Bafang 12T (in a 26 inch wheel) and battery from EM3EV.
Good luck with whatever you decide.
It is important to find a bike you're comfortable with, one that will take the weight in stride, and one which allows for conversion. I found all three in the Expressway I mentioned earlier (to be clear: I haven't converted it, but would be totally comfortable doing so).

I'm not sure about all of Dahon, but the few I've seen seemed shoddy in their build quality. Maybe "lighter duty" would be a better way to put that. Higher quality folders will cost you (Bike Friday for example), and cheaper ones will probably disappoint you for this. You have to select one that best for your budget, requirements and preferences. That is entirely up to you, glockjs. Unfortunately there's quite a field to narrow down!

On another note, in my view, writing off one entire class of bicycles as unsafe for anyone is short sighted. Unless you've ridden literally the majority of them, your opinion is just that, an opinion... even if you had ridden all folders in existence it would still be an opinion colored by your personal tastes and experience. I wouldn't personally accept opinions as doctrine.
Yeah. I'd have a hard time recommending my older Dahon to anybody. I had and still have a lot of fun with it. And while it doesn't instill confidence, I figure I probably commuted on it for over 1000 miles on it and it never failed me. I did upgrade the brakes tho. I was about 155 lbs at the time and could sprint to 30 mph on that thing because the 16 inch wheels loved to accelerate. But it wasn't "safe" at that speed by any modern standard. The trick, of course, was to understand what the bike could do and ride with its limitations in mind. If you had to brake hard, you gotta push way back off that seat.