Refitting an e-scooter with a belt drive motor & Life batt.

[pengyou]

I will be moving back to Shanghai soon and want to buy an e-scooter that looks something like this: http://www.mankoomanufacturing.com/elec ... ooters.htm They are not very well made, I know, but my biggest complaint with them is that they are really heavy. A scooter with a 20 amp 48v sla weighs in at around 140 pounds. This takes more juice to move around but the worst problem occurs when in an accident and you find the scooter landing on you - this happened to me I want to replace the hub motor with a tournigy and belt and then the sla with a life pack. I have looked at a lot of scooters and most of them have room for this kind of motor set up. Has anyone done this before? any suggestions?

[charliebruce]

You could perhaps email them with a technical enquiry and ask for a close-up or technical drawing of the rear wheel assembly - they might not oblige, but you lose nothing by trying. My biggest struggle was coupling the motor to the wheel, so make sure you have a solid plan in place before you buy anything.

Would replacing the cells, and rewinding or replacing it with a bigger hub motor not be a better idea than a completely new drivetrain?

[pengyou]

Would replacing the cells, and rewinding or replacing it with a bigger hub motor not be a better idea than a completely new drivetrain?

Thanks! Replacing the motor with a bigger hub motor is going to make the motor heavier, and thus the bike heavier. One of the main goals is to make the scooter lighter, and not necessarily faster. I probably could replace it with a geared hub motor, which would cut the weight of the motor in half. The rear wheel is on a swing arm which, I think, will provide enough room to install one of the heftier turnigy motors. A side benefit of doing this is that the performance of the scooter would be enhanced positively, but that is not the main objective. I usually ride in rather heavy traffic so speed is not much an issue, though an increase in acceleration would actually be a safety feature IMHO.

[TylerDurden]

Why not an ebike, rather than a scooter?

[pengyou]

E-bike vs e-scooter...that is a good question to consider. First reason, the smaller wheels of the scooter make it more suitable for city riding. Secondly, the scooters with the battery in the floor panel have quite a bit of storage under the seat that is protected both from the weather and roving eyes. Thirdly, most scooters can easily accommodate a second rider with reasonable comfort, at least for a short range. Finally, the plastic/fiberglass on the scooters makes them a little heavy and probably gives more wind drag but it also provides a little more protection against road rash . Even so, I still considered a conversion - always the much preferred option...but I do not have the time or tools to do so. The ebikes sold here are extremely uncomfortable, have no storage and do not usually have a rear suspension. They also have the same "boat anchor" batteries and motors.

My dream..but it has eluded me for 3 years...is to convert a lightweight folding bike. The problem I had was that I was trying to convert the bike that I was using as my daily rider and could not afford to have it down for a couple or few days to play with it. I want to stick with 48 volts on this project so that I can also use the battery pack on the next project, if it ever happens. I am pretty confident, though, that it will happen by next summer. I want this second bike because, when folded, I can take it on the subway or trains in China at no extra cost and then have transportation when I get to my destination. I ran into issues with my wonderful Dahon - the rear drop outs were not suitable for what I wanted to do...but I will look into another as soon as I get my new wheels.

[TylerDurden]

A bike like a Yuba Mondo might get most you the features you want, with less weight and less drivetrain complexity than a scooter conversion.

[pengyou]

Yes, you are right but the length of the bike is an issue. The size of the wheels makes navigating in close quarters in the city more difficult. I know this for a fact from the last ebike that I had - had 24" wheels and was really troublesome to manage in the "packs" of 2 wheeled traffic that accumulate at stop lights in Shanghai. That is why most of the scooters here have 12" wheels - a few 14" or 16" with a couple of combo escooters measuring in at 18". The small size of the wheels is the main reason why I want to move to a belt driven drive train. I am guessing also that the bike pictured would be too long for the parking spaces created for 2 wheeled vehicles. I would like to do touring some day soon. If I can do that, I think the Yuba would be perfect - just install a 350 watt geared hub to provide some supplementary power. If I do a conversion, I would go ahead with my plans to use a 20" folding bike but I cannot find one that will support the weight of two people.

I often think that the ideal form of transportation for me would be a semi recumbent (semi meaning not completely reclined) tadpole trike, 2 wheels in the front, short wheelbase with pedal power to the rear and and twin electric motors up front. The wheel base is relatively short, provides a good platform to pedal, would still have good visibility and also makes provides space for storage - even a second person in some that I have seen, though I am not sure about the wheel base of those models. The immediate downside that I can think of is that this kind of cycle would not be very stable at speeds over 15 mph

A bike like a Yuba Mondo might get most you the features you want, with less weight and less drivetrain complexity than a scooter conversion.

[motomech]

Your posts are full of generalizations that are debatable at best.
I don't get your reasoning about smaller wheels being the way to maximum maneuverability. It's a combination of a lot of things, center of gravity, wheelbase, overall weight, rake and trail of the forks, etc. The most agile of all 2 wheeled vehicules, trials bikes have big wheels. The reason scooters have small wheels is to make space for the floor board. And then there is the down-side to small wheels, potholes. Are there no potholes in Shanghai?
Actually, wheel size is a moot point. The single most importatant factor in congested, free-for-all city riding is width of the handebars, the ability to squeeze between traffic and other obstacles. And here, an Ebike ould have the advantage over an Escooter.
By that as it may be, rather than reinventing the Escooter, why don't you do some legwork once you are there and find the best model available and work with that. Batteries, controllers, hub motors and wiring are all easily up-graded. Besides all the complications of engineering a belt drive/RC motor system, it would eat up space that could be used for batteries.
Besides, your sweeping comment that that Escooters are not well built is true in the sense that the sub-systems are substandard[compared to the Japanese offings]. Things like the general wiring, body panels, hardware, suspension components etc. are the weak areas. The hub motors and controllers are the most realible systems on those scooters and replacing them does nothing to address the Chinese Escooter weak points.
If you start with a scooter with a trailing-link frt. fork, you could mount a second hub motor for 2wd, which I.M.O., would make for the ultimate urban Street-Fighter Escooter.