Electric bike conversion

Does anyone know if it possible to buy an electric bike conversion that:

is front wheel drive

i.e. is fully street legal and safe.

FWD might be the problem: the need to fit a motor which is light enough not to make the steering very heavy, and the problem of making the power cables from the battery cable of carrying the power (250-500 W typically) without making the cables very stiff, given that they have to turn with the front fork.

Getting it to respond to the pressure on the pedals would be interesting because it needs some sort of strain gauge in the pedal-chain-gears drive-chain but that is separate from the mechanical aid that the motor is giving, unlike a conventional e-bike.

Is there some reason why you need it to be FWD? Are you making a rod for your own back with that requirement?

It is how my ancient, defunct powabyke is configured, useful offroad and possibly.

I was hoping just to swap the wheel

I built a 36V FWD one of these:

If you don't fit the throttle it only works by pedalling. There is a setting in the display to limit the speed to 25kph (=15mph). Motor powers are a bit hypothetical because it's supposed to be a 250W continuous rating but there's no regulations on what the instantaneous power is supposed to be. If it has 250W written on the outside that's all that matters.

This kind only have a cadence sensor rather than a torque sensor, so they detect the pedals going round instead of force on the pedals. That means you don't get assistances until the pedals have gone around one notch on the cadence sensor, so you still have to move the bike manually for the first fraction of a rotation. Not a big deal in practice, but not as nice as the torque sensor.

Can't remember if I ordered direct or from their shop on Aliexpress (think it was the latter), but it arrived ok (box a bit battered but no damage) and worked fine.

Theo

You can kits of all the bits you need. e.g:

Fitting is probably a bit easier than on a rear hub kit. Mine has been going strong for well over 5,000 miles now. The battery is being to lose some range, but still does enough:

Whoosh are highly regarded among the ebike community - decent products, well priced, good UK support. If you don't know where to start then talking to Whoosh is a good plan.

Buying the parts direct from China is cheaper, but you have no support except yourself. Personally I'm happy with doing that, but YMMV.

Theo

My feeling at the time was I would rather go for a known working combo of parts for my first attempt, although now I would be comfortable buying separate bits if doing it again.

I will probably some things differently next time. I would want the battery on the down tube and not on the rear rack - I find it makes the bike tail heavy and rather wobbly if trying to ride standing.

Many of the bits that make a difference are also the spec of the bike itself rather than the "e" bit of it. Starting with a more modern frame with disc brakes would be good. Suspension tube on the saddle would be nice (the weight on the rear wheel helps you feel every pothole!)

I expect a single rear derailer with 8 speeds would be fine (I stick to the large front cog all the time now) - doing away with the added weight and complexity of the front one. Have to say the Shimano indexed shifter is very good - push a button to click up through the gears. (you shift faster on an ebike).

I quite like the rotation sensing drive rather than torque sensing. I tend to leave it on full power most of the time unless moving in slow traffic on in a busy shared pedestrian / bike area. I typically ride a little bit faster than the top speed limit of the assistance, so only relay use the power on hills, into head winds and for pulling away. (or if particularly knackered!) I would also be happy with a 13 to 15Ah 48V battery - the larger ones probably provide more range than I need and add weight.

Personally I’d stick with a company with a good reputation. Buying cheap from the far east is fine when the only risk is financial.

The risk with ebikes is in the battery. A lot of the times it's people charging one battery with a charger designed for another, typically a 36v pack with a 48v charger - they often have only a basic barrel jack and there's nothing to stop you mischarging.

Also some batteries don't have the best BMS or proper thermal sensors to cut off charging if an overheat is detected.

That means you should be careful where you buy your battery from. It doesn't impact what kind of motor or conversion kit you fit.

Theo

It's difficult to tell how many of these examples are dodgy kit, bad luck, or simple misuse. But in any event decent provenance is a particularly good starting point when buying an electric bike.

I bought a Bafang kit about 5 years back - crank motor and downtube-mounted battery. It was pretty much ubiquitous at the time, and had a good reputation. So far so good, although I've only done a few thousand miles on it.

Thanks for that, the marketing seems a bit confusing

Thanks everyone, I'll read the faq.

The parts are not available for the powabyke, so swapping a wheel make sense and if the battery is light and easily removable it shouldn't attract thieves.

Unless the Powabyke is a particularly good model or with something you can't find elsewhere I might suggest it's worth thinking about converting a 'normal' bike. Old-school ebikes were often very heavy - big steel frames, lead acid battery, chunky motor - and not actually that great as bikes without the power assist. A normal street bike from somebody like Ridgeback is a lot lighter and better specced than an older ebike, and can be picked up second hand for not-a-lot (£20-£80 looking at ebay sold listings). The conversion adds weight, but not hugely, and you can always use it without the battery as a regular bike if you prefer. The only thing that a dedicated ebike gets you is better integration of the battery and the wiring, but that doesn't really apply to a retrofit unless you're doing things like putting new cells in the old battery case.

Theo

My council did a free ebike loan for a month - I got a Specialized road bike, something like this:

But overall much nicer - and my donor bike is a half decent 10kg mountain bike.

But if you have the money, I would suggest trying it. Or try it anyway and live with not being able to afford it :-)

For the benefit of the audience, is this the bicycle you are attempting to "convert to something modern" ?

And I think the ally "tub" on that thing, is welded to the frame.

Your project might be easier, as someone already suggested, getting a used bicycle from a reputable recycler shop that has reconditioned the bike, then adding a new front wheel, pack, throttle, sensors or whatever. Because a regular bike has more room for fitting all the components.

Paul

I agree and I have two ordinary bikes , one of which I could convert.

The powabyke is heavy, under geared for normal use, old and worthless but I want it to go shopping for a month and it is otherwise scrap.

OK :-) Not sure what wheel size it has, but if it's a standard size like

If you wanted to alternate between old and new, all the parts are easily available on Aliexpress so an easy swap might duplicate some of the cheaper parts which are more finnicky to install (sensors, controller, display, wiring) and then you're just swapping wheel and battery.

Theo

Just to follow up I contacted the kit ebike firm and their battery controller kit will not work with the brushed motor in the powabyke . They could supply a hub, battery, controller and brake switches which would all fit if I had the 24" wheel re spoked.

So I decided to order a kit for a 26" wheel old Raleigh, steel tube mountain bike for about £650. Bearing in mind I only want to go 2 miles to the nearest town for shopping and don't want to attract thieves, so I want a battery light enough to carry whilst shopping. The firm will not supply a kit to be used with other than a 20kWh rack mounted battery which is not very portable or a 10kWh one that is fixed to the bike.

I am sure I have seen a battery that fits to the handlebar like a basket.

The reason for wanting electric assist is for one hill that sends my heart rate up over 150.

I'm tempted to just add a 10A push button and a 40V drill battery to the Powabyke though I did want to be legal.

Incidentally I see Evans bikes sell cheap ebikes but they are all over 250W.

There’s nothing intrinsically bad about going over 150. It’s more about how you feel! I go over 170 or even 180 on occasions. (Age 68).

Tim