Folding e-scooter advice

ElectricGod

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Hi folks,

I'm considering getting a small scooter to upgrade. I've had my eye on several small folding EV's for a while now and this one seems to be the best of the batch of small Chinese scooters in this class. Please post any experience you have with these models specifically. If you know of a small folding scooter that is well built and doesn't cost $1600, then feel free to post them here. If you've found videos or tear downs or comprehensive reviews on either of these EV's please post them here. I'm not dead set on these specific EV's. I will be upgrading it so I can get 40-45mph and 25 miles or more out of it. Thanks for your help.

Things I consider requirements:
1. full suspension front and rear
2. disk brakes front and rear
3. small and foldable so I can keep it at my desk when at work.
4. durable

The Lehe K1. For the most part the build quality looks pretty good. It can be found on Amazon and e-bay for less than $900.

Full%20bike%202.jpg

Full%20bike.jpg

Front%20wheel.jpg

rear%20brake.jpg

Folded%20down.jpg

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This is the one part that worries me. The hinge mechanism is what holds it all together. There's lots going on here. Does anyone have any experience with how well it holds up? There's a tiny latch on the side that locks it all together. I have no idea what it actually engages,. Hopefully it's more than a small pin.

Latching%20mechanism.png


This is the other EV I just today found. It's pretty much the Lehe K1, but with some new features. Probably the biggest one is that it unfolds and folds itself via several motors and worm screws. I found a video of this happening. It looks cool, but not really of great importance and probably a failure point. The main frame hinge unfolds, the seat goes up and the steering tube extends upwards all with the push of a button. It's essentially the same EV as the K1 otherwise.

RK-1%20scooter%202.jpg

RK-1%20scooter.jpg
 
ElectricGod said:
I will be upgrading it so I can get 40-45mph and 25 miles or more out of it.
I've not used any of this particular class/style of scooter...but some thoughts:

Based on my experiences of small wheels (10-12"?) like these (even at much lower speeds), I'd hope your roads are perfect, for speeds like that. Otherwise, I'd get something with larger diameter wheels, both for ride quality and safety in case of potholes and the like.

The "suspension" on these is probably not very good, having been intended for their nominal ~15MPH design speed, and probably intended for sidewalk-riding-scale bump absorption--it's probably worse than that on really cheap bikes.

Brakes and whatnot you can upgrade easily enough, though I suspect any sudden stop requirement from 40-45MPH on one of these is going to have a risk of flipping over the small front wheel if you have to lock it up.



I'd guess from the volume I see available you'd end up with a backpack battery to get the necessary Wh for the speed/range desired, to avoid external packs being in the way of folding it up.
 
My Currie stand-up scooter has this exact wheel size. I go 40+ on it. I ride in multi lane traffic with cars and trucks on it. I replaced the factory brakes with rotors and decent, but cheap mechanical calipers. It stops pretty well. I've clamped down the brakes hard multiple times to make sure they work reliably. There is always the possibility of flipping over the handle bars on anything. Anyway, my Currie runs at about 4kw, tops out at over 40mph, has only front suspension and I ride it on the streets all the time. Obviously I avoid pot holes, but it manages entry ways into drive ways, major cracks in the road and typical road way anomalies just fine. I'm not overly concerned about the wheel/tire size. The front suspension on the Currie is a bit light, but since it's just springs in there, I bet I can replace them with stronger ones of add a smaller spring inside the bigger one if needed. So far it hasn't been a problem with the factory suspension. Admittedly travel is a bit short...about 1.5", but then the bottom of the battery box is just 2" off the ground anyway so more travel would be bad.

The pack would be on the EV on the rear tube. That's just details to work out...18650's to weld up and so on. I don't care if it extends beyond the frame dimensions. I can work that out once I have the EV and I bet I can make it fit inside that triangle between the front tube and the back tube when it's folded up. I do agree that very small tires make road riding harder so I don't want to go smaller than the 12.5x2.25 wheel size that the Currie already rides on. Fortunately with the Currie build came several discoveries of good options in this wheel size. The EV will get heavily modded no matter what model it is. I've already been hunting for a much larger hub motor, but most won't fit between the drop outs. That means scrapping the idea of a single larger hub. I have considered dual 350 watt hub motors just to keep it clean looking and as quiet as possible. Dual hubs is still only going to get me around 700-800 watts which is weak IMHO. Scrapping the hub motor idea is 100% fine with me since I'm not fond of hub motors anyway and I want more than 800 watts...more like 2000 watts at least. Using an outrunner and some chain to the back wheel is how all my previous EV's have been built and probably how I would do this build too. I'm curious to see if I can get 219 between the drop outs and the wheel. The factory controller will obviously get scrapped and I'll have to figure out what bits of the factory electronics can be reused and what can't. I'm not the least bit worried about buying a new EV, voiding the warranty and modding as needed. That is the plan. Motors, controllers, battery, electrical are all going to be intentionally replaced. I've already decided to see if I can get an XHP70.2 LED to run in place of whatever the factory light has in it...probably a Chinese Cree T6 is my guess. MOD until it breaks or until it goes really fast is my motto!

I'm looking for specific feedback about these EV's. What's good, what's bad. How well they hold up, construction quality and so on. It is probable that I will buy one, but I want to make the best choice I can too for my starting platform.

This is my Currie scooter as it exists right now. The frame is more or less "factory" and then everything else has been replaced/upgraded. I bought it used and didn't care if it worked or not. The entire build thread is in my signature. I'm not the least bit afraid of heavily modifying something. If you don't lean forward when you hit the throttle it will throw you off the back or at least pull a good wheelie and accelerates really well.

Currie%20scooter%20complete%2016042017%203_zpswogarwit.jpg
 
If the tires would fit on a common ebike hubmotor's spoke flange diameter with some room to spare, you could machine rim flanges that would bolt to the spoke flanges.

Might take some wrangling to get the valve stem thru, but 90-degree stems might be used for that, and some creative angling of the stem inside the tire.

Or go tubeless and build the stem into the flange like a car rim.


That would get you at least 1kw in each wheel with two motors, or use a hefty single motor and do however much you want in a single wheel.

Less wheelie problem with two driven wheels, though, especially if you can make a weight-distribution-sensor-driven throttle-divider, that basically takes your throttle input and tells each controller to power it's motor inversely proportionally to the weight distribution (so if a wheel lifts it provides less power to the other wheel and more to the lifting wheel), as well as sensing the traction each wheel has (so you don't spin out a tire).

I'm not exactly sure how that would work, but in theory it should keep you rubber-side-down. ;) JustinLE has probably already done work you could adapt from his skateboard builds.



FWIW, with that much modding, I'd just design and build one from scratch to do exactly what I wanted, without worrying about what surprises teh factory might've left me to find (especially mechanical ones). ;)
 
amberwolf said:
If the tires would fit on a common ebike hubmotor's spoke flange diameter with some room to spare, you could machine rim flanges that would bolt to the spoke flanges.

Might take some wrangling to get the valve stem thru, but 90-degree stems might be used for that, and some creative angling of the stem inside the tire.

Or go tubeless and build the stem into the flange like a car rim.


That would get you at least 1kw in each wheel with two motors, or use a hefty single motor and do however much you want in a single wheel.

Less wheelie problem with two driven wheels, though, especially if you can make a weight-distribution-sensor-driven throttle-divider, that basically takes your throttle input and tells each controller to power it's motor inversely proportionally to the weight distribution (so if a wheel lifts it provides less power to the other wheel and more to the lifting wheel), as well as sensing the traction each wheel has (so you don't spin out a tire).

I'm not exactly sure how that would work, but in theory it should keep you rubber-side-down. ;) JustinLE has probably already done work you could adapt from his skateboard builds.



FWIW, with that much modding, I'd just design and build one from scratch to do exactly what I wanted, without worrying about what surprises teh factory might've left me to find (especially mechanical ones). ;)

That's fine if you have a machine shop which most of us don't have. I sure don't! If I can't build it in my garage, it's probably not going to happen. AKA...prebuilt and reliable construction to start from takes loads of the work away that I can't do myself or have someone else do and have it cost a fortune.

Hubs are unsprung weight...not really an option IMHO.

Do you know if anyone has done traction control? I'm thinking about possibly building a recumbent trike in the future. IT will be 3 wheel drive with independent motors and controllers for each wheel. I'll probably do away with all the human powered components too...if I build it. However since both front wheels will be driven, I'll need to adjust their throttles so the outer wheel runs faster than the inner wheel and proportionate to the turning angle. The back wheel would run at the midpoint between the inner and outer front wheel speeds. In straight line acceleration, it would be possible for a wheel to lose traction. You don't want to have the other front motor pull you into a spin. I was thinking a little coding in a nano would do the trick. The motor speed wire on each controller would provide the wheel speed input. A position sensor or POT would provide the angle of turning at the handlebars. Nano's have several DACs. I think they could be used for the 3 throttle signals to the controllers and an ADC for the actual throttle input. After that it's just some coding to compare the front motor RPM's and add or subtract some throttle depending on steering angle or for wheel spin. It doesn't sound hard in concept.

So anyway, back to these little EV's anyone have actual experience with them?
 
Hi,

I'm looking for a worth while small fold-able EV that is mechanically reliable. Something like I posted above. If you have opinions on the above products. Please post them.
 
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