Converting Your Bike To Electric: Why You Should, And When You Shouldn’t

A decade ago I was lucky enough to work for an employer that offered a bicycle loan scheme to its employees, and I took the opportunity to spend on a Brompton folding bike. This London-made machine is probably one of the more efficiently folding cycles on the market, and has the useful feature of being practical for longer journeys rather than just a quick run from the train. A 3-speed hub gearbox is fine for unhurried touring, but sadly my little folder has always been a bit of a pain on the hills. Thus around the start of the pandemic I splashed out again and bought a Swytch electric upgrade kit for it, and after a few logistical and life upheavals I’ve finally fitted it to the bike. I’ve ridden a few electric bikes but never had my own, so it’s time to sit down and analyse the experience. Is an electric bike something you should have, or not?

A Box Of Bits Becomes An Electric Bike

All the parts of a Swytch kit
All the parts of a Swytch kit. From the Swytch assembly manual.

Swytch sell their kits via crowdfunding rounds, so I’d been on a waiting list for a while and got an early-bird price on my kit. It took quite a while to arrive, much longer than the expected time in mid-2020 because of the pandemic, finally being delivered some time in February last year. It came in a modestly-sized cardboard carton which would be an easy carry on the Brompton’s luggage rack, containing neatly packed a new front wheel with motor, as well as the battery and all sundry parts.

Fitting the kit shouldn’t stretch the capabilities of a Hackaday reader, with probably the trickiest part being the positioning of a Hall-effect sensor near the crank. The kit works by providing a motor assist when you pedal, so part of it is a set of magnets on a plastic disk with various attachments for different cranks and pedal sets. The Brompton front wheel is removed and its tyre and tube transferred to the Swytch one, which is then put on the bike. Once the magnet disk and Hall sensor are attached, the cables follow the existing ones and emerge at the handlebars where a sturdy bracket for the battery box is fitted.

The Swytch Kit First Impressions

The motor is a compact unit, more so than I expected.
The motor is a compact unit, more so than I expected.

The battery also contains the electronics and motor driver, and provisions for brake sensors and a hand throttle, which I had not ordered. My kit is painfully UK road legal with a pedal sensor, software-limited 250 W power, and around 15 mph top speed. I could have ordered it with no limits and all the extra toys to make it more like a small electric motorcycle, but even though I can remove the software limit I can’t negate the risk of a roadside inspection and fine if I did so.

Swytch offer two battery packs in 30 km and 50 km range sizes, and of those I bought the larger one. After charging it up, I turned it on and clipped it in the bracket. Ready to test a new toy on the concrete apron behind my hackerspace!

The Swytch battery pack comes with some controls on the top, the main function of which is to vary the amount of electrical assistance. This is best described in terms of who’s in charge; at maximum assistance it’s the bike that’s doing the pulling and all you need to do is move the pedals, while at the minimum it’s a handy aid that smooths out the effort and makes cycling a less strenuous exercise while leaving you definitely in control.

The Swytch battery pack on the Bromptoon handlebars.
The Swytch battery pack on the Bromptoon handlebars.

There’s one minor snag: in some conditions the motor vibrates instead of starting smoothly. From my experience with AC motors for Hacky Racers and other machines I am guessing that this stems from the motor feedback to the controller being via back EMF sensing rather than Hall effect devices, so what I’m seeing is a temporary loss of that feedback. It’s usually quickly cured by stopping pedaling and restarting after the motor has cut out, something that doesn’t significantly impede progress.

I’ve used the bike a lot for general riding, but I’ve also set out to work out the real-world achievable range with a few longer cross-country test rides with it on low power mode to assist rather than replace my cycling. As expected, I never managed to crack 50 km, but I came pretty close.

My routes weren’t ideal with a few inclines and on one of them some stiff headwinds on the day I did it, but even so I achieved between 40 km and 45 km, which I count to be not too bad for a 50 km battery. Once the power is exhausted, there’s a perceptible drag from the motor, but it doesn’t render the bike unrideable.

So What’s An Electric Bike Like To Use?

The description of a Swytch kit aside, it’s time for some more general impressions about electric bikes based on a while using an electric Brompton as daily transport. There’s even a handling angle, as the bike is now an all-wheel-drive vehicle. How does it change the riding experience?

The electric Brompton in all its glory
The electric Brompton in all its glory

The first impression of an electric daily rider might seem obvious in that it’s now much faster. I could reach the mid-teens speeds before but only with some effort, now they’re within reach any time I want. This is great for getting from A to B, but I’m also acutely aware that I can get into trouble a lot more quickly. Oddly I have found myself riding much more cautiously, particularly in town where there are pedestrians and traffic.

With electric power at the front and pedal power at the rear, the bike is now a two-wheel-drive vehicle. Two-wheel-drive motorcycles are so vanishingly rare as to be restricted to a very few small-production models, but courtesy of my friend Russ’s electric minimoto conversion I was given the rare opportunity to ride one at EMF 2018.

It was notably sure-footed on the gravel roads of the EMF campsite, but suffered from a pants-filling moment  on start-up as the front wheel would spin while the rear had traction. By contrast, the momentary delay afforded by the Swytch pedal sensor system was enough to ensure that the Brompton was moving before power came to the front wheel, ensuring that even on loose surfaces there was never any unexpected wheelspin.

The resulting two-wheel drive makes a noticeable difference on surfaces such as grass and loose gravel that would normally challenge the Brompton, and when giving it a spirited ride on tarmac the extra traction can get me out of trouble. It’s dangerous to become addicted to fast tight turns with rear wheel slide, though, because when the inevitable happens and the front wheel lacks the purchase to pull me out of it, I can see that the results could be painful. The sight of a middle-aged woman exorcising her teenage BMX dreams on a folding commuter bike must be amusing to watch, but at least I was having fun.

So, should you go electric with your bicycle, or is it all a bit pointless? After all it’s not entirely cheap, and you have to pay for a bike on top. The answer is that if you’re fit or only ever riding short distances, then perhaps it’s not essential. But if you ride medium distances, and perhaps most importantly if you ride to places for which it’s important not to arrive a sweaty mess, then the electric bike is a worthwhile upgrade. The Brompton’s not my main bike, so I use it for trips where I need to take it on a train or in a car, and I value the Swytch kit for the extra range it gives me while keeping me from looking over-exerted.

Oddly there’s a use case for which an electric bike would be unsuitable, namely longer distance riding. The thought of riding for more than a short distance against the extra drag of the motor isn’t appealing, so the Brompton’s now a bike with an effective 50 km maximum range. I frequently use my everyday bike for longer trips, but for your only bike it’s worth bearing in mind.

Electric bikes aren’t for everyone, but perhaps is 2022 the time to give them a try?


96 thoughts on “Converting Your Bike To Electric: Why You Should, And When You Shouldn’t

  1. I still just can’t get over that 15MPH top speed. When I rode more often I used to exceed that all the time without any assist. Are you not allowed to pedal faster than that or is it only a limitation for powered vehicles? Or is London too crowded for this to be a real issue there? I did my cycling on suburban and/or country roads.

    1. On a folding bike with tiny wheels, 25 km/h is already quite a lot.

      Did you ever feel like needing assist when you were cruising 30 km/h in nice weather on flat road?
      For me, the biggest point in electric assist is making the climbs and headwind more tolerable, which are not conditions where you would easily exceed the speed limit.

    2. I believe that if the power assist works when over 15mph or when you’re not pedalling then it’s classed as a motorcycle and needs insurance, etc. The power assist should just cut out if you’re over 15mph – whether by your own effort or gravity – and back in again once you’re moving a bit slower.

      It’s normally easy enough to disable this “feature” if you want to accept the risk of getting stopped by the police. As you’re now on a motorcycle I suspect you could have your driving licence endorsed, so not just a fine.

      1. I think a bigger problem for the police would be catching someone on a fast e-bike. In a city, the bike can probably go as fast as any police car, whilst also going down alleyways that the police can only follow on foot.
        I’ve seen a few in use around here, and they look like a fat mountain bike at first glance, until they rocket up to 30+mph.

    3. Yeah, i found this hard to believe. What do the police do – disassemble the code? Of course, no doubt you live in an area far more dense than most people in the US ever even experience.

      1. Probably just give it a test ride and see if it goes faster than 15mph?

        On one hand, it’s way too fast for half the idiots on our roads, and on the other, as someone who commuted by bike for years and averaged 20mph door-to-door (ie 25-30 on flat straights) on the 15mi commute, it’s so slow as to render the entire thing pointless.

        But on a Brompton, seems like a good fit. And obviously if your work doesn’t have a shower you can use each morning, you don’t want to be going that fast under your own steam.

        1. Agreed its a rather low limit, back when I last cycled regularly I’d be over 30mph on the morning outbound (fairly flat but averages slightly down hill) and still over the e-limit on the return everywhere except the one steeper hill bit most days (when really tired maybe I’d be cruising along around that speed).

          But I do see a use for it beside the tiny folding type bikes – if you have to deal with serious hills all the time, down is all well and good but getting up hills really isn’t fun on a bike, even more so on the busier roads.

        2. Police (in Denmark) have an board with a set of rollers and a speedometer for testing mopeds etc.

          Bicycles are required to adhere to the speed limit as well as cars. For mopeds (in Denmark), they are limited by law to be able to go no faster than 30 km/t (for standard) or 45 km/t (for EU-scooters).

      2. DIY e-bikes are a gray area because there are no rules on how to police them.

        There’s no way for the police to check that there isn’t a secret bypass switch in your controller, that your motor is actually as powerful as the nameplate says, etc. except where there exists documentation from a manufacturer that can be referred to for checking that the device is legal to begin with and hasn’t been tampered with. With kits and DIY, this isn’t available.

        In other words, if the police decide to be difficult about it, they have the grounds to simply confiscate your bike and take it away on a “reasonable suspicion” that you have a trick device and are simply pretending to be adhering to the regulations. There is no way for you to prove to them on the spot that this isn’t the case, so you’ll have to go to court.

        1. My E-bike (not finished) used to be road-legal. i.e. a manufacturer swears that the motor is 250W. But boy is that motor powerful! Well over 500W I’d say. (that said: I still have to figure out how that’s possible: IIRC I’ve set the software limit to 300W in the current situation).

    4. It’s a legal thing. They’re no longer exempt from all the motorbike/moped rules if they can exceed 15mph on electric. Most people I know have removed this restriction on their bikes. You’re extremely unlikely to get caught but I suppose if you were in am accident and someone got hurt you might be in a lot of trouble.

    5. The rule is: No assist allowed above 25km/h (in Europe). (15.6mph). Maybe it’s 15, maybe 15.6 in UK/USA. I don’t know.

      If the battery voltage is such that the motor can’t turn faster than say 35km/h, then at that speed, you’ll start charging the battery no matter what. If the limit is in software and you have the same battery… then whatever is claimed as the top speed, is what you can pedal by yourself (or downhill).

      In the old days (i.e. before electric assist on bikes) you’d get tired from going faster than 25km/h. Witth assist, it is so easy that you’d be a danger, mostly to yourself. So safetyrule: You get assist up to 25km/h. If you can pedal faster, that’s fine. That’s the reasoning.

  2. I never thought about it until seeing this design, but powering off the front wheel will put a lot of torque on the headset. Wonder how that works out long-term?

    I mean, bikes _must_ be designed to hold the front braking force, and pulling a stoppie has your whole weight behind it, so maybe it’s no big deal.

    Still, must feel crazy to have all-wheel drive on a bike.

    1. Hub motors don’t actually have a huge amount of torque, much less than what pedaling produces.
      It can, however, cause damage to the small metal flanges (dropouts) where the wheel axle is mounted.
      Sometimes extra torque arms are mounted to reinforce it, similar to what rear hub brakes use.

    2. Well when I had to pull a stoppie as part of avoiding action I did bend the front forks once, on a mountain bike too, not some thin spindly road bike! Probably didn’t help the poor thing that back then I must have been at least 100Kg (Rugby hopeful) and it was downhill from pretty high speed on a not super smooth road…

      So I wouldn’t say its not a big deal at all, its well worth considering before you pick a bike to modifiy, that said it shouldn’t pose too much trouble – to be road legal you are limited to a paltry 250w, so to get a useful speed out of it I can’t imaging the torque of any of these kits is particularly impressive, really should be in spec for the frames.

    3. When you hit the brakes hard, you can be dissipating thousands of watts, albeit briefly.
      The wear on headsets, though, is almost always on the front from the rider weight, over the long term.
      It’s been my experience that the forks will fold/bend before the headset is damaged, at least in a crash.

  3. I built a mid motor ebike to commute in sf and it was a monster. I used a kit and custom built battery from em3ev. In would never use a hub motor, or such a tiny battery on a human vehicle. My battery probably weighed 20lb. I tried to test its limits once and rode for 4 hours at 22mph without even peddling and didn’t run it out. The mid motor is also amazing. It can ride up a 45 degree incline at like 15mph no problem. It feels like being on a roller coaster when a chain is pulling you up. The kit in the story looks like a toy IMO. Granted my bike does look like a rolling science experiment.

    1. It’s a very different type of kit. It’s designed for Euro road legal bikes. Yours would be classed as a motorcycle here. It’s also designed to be lightweight. This is a bike that folds up small enough to sit on your knee on a train ride.

        1. We’re gonna end up with the RC Aircraft vs Quadcopter thing playing out over again though when any idiot with a credit card can buy the high power off road models and kits and hoon them around on the public roads. You’ll tell them to either comply with cycling, low power eBike or motorcycle regs, and they’ll be all “But it’s not any of those hurr durr” and then the law abiding public will get hit with heinous new regulations where buddy will revert to “It’s not against the law if they don’t catch me.”

    2. Why wouldn’t you use a hub motor for a small battery, but a mid motor?
      They are power limited by law anyway. In EU, it’s 250W.

      I really don’t like mid motor.
      You can’t have regen, it wears up your whole drivetrain. With a front hub motor, you get an AWD bike (it’s great for rough terrain).

  4. I also have a Brompton I electrified, but using the motor/wheel and controller from the Nano system. But rather than modify a bag and the bag mount as per Nano I attached a bottle battery to the frame and can swap it for a spare for greater range).

    With the Nano motor I don’t notice any motor resistance when unpowered: I can propel myself on the flat just as easily but for my aging artheritic knees I can get a bit of assistance when needed uphill. It works very well for me.

    15mph is fast enough for me around the narow pothole-peppered rural roads where I live. The little 16″ wheels really are not good down pitholes!

    1. I got the nano motor as well but I use Dewalt batteries as power. I started with two 5 amp batteries (so 36 volts at 5 amps ) but now have made a 4 battery setup (10 amps at 36 volts) good for 20 miles plus at full assist. As regards to speed I did used to average at 15mph on my Brompton but I was riding through city traffic 10 or 20 miles every day regardless of the weather, so got to a good level of fitness. I got the motor simply because after two years of not going to the office my level of fitness is not what it was. I was put off by the Swytch bike kit by some of the reviews and the battery pack when it goes does not appear to be cheap, but Dewalt batteries are very cheap.

      1. I have the same concerns about the Swytch kit. The new one (2022) in some respects for the Brompton, is a step backwards because in order for the fold to work the battery carrier has to be mounted behind the handlebars facing the rider, or to get round that they’ve brought out a holder which fits on the luggage block meaning you lose the luggage block, that’s a big no-no for me.
        Where did you get the adapter for the Dewalt batteries to interface with the nano kit?
        and, is it just 2 x 18V in series with no electronics? (a photo would be great).

    1. Especially in low gears where the front wheel gets light and less grippy.

      Built an e-bike for fun many years ago. About 1500W and not limited but not for road. Wheelies were a problem. Rather fun one.

  5. If you’re a hacker, making an E-bike is crazy cheap, easy, and lots of fun. For 20 years, I taught classes of 4th-6th grade students to invent/build/race their own electric vehicles. None cost over $100 US. Most were built from old bicycles, scrap lumber, metal shelving, etc. — things the kids scrounged up themselves.

    A typical setup was a 12v car heater blower or radiator fan motor, a sealed lead-acid battery and its charger from a scrapped scooter, and some kind of switch mounted on the handlebars. A “wheel” about 2-3″ in diameter was pressed or glued or screwed onto the motor shaft. It could be a skateboard wheel, or the wood plug made by a hole saw, or a doorknob; whatever they could find.

    The motor with its wheel was mounted above the bike’s front or back tire with a door hinge, to drive the bike tire by friction. The angle is chosen so if the motor is not powered, rotation of the bike tire pushes the motor’s wheel forward, away from the tire. But when the motor is powered, its torque reaction pulls it rearward, so the friction wheel is tight against the bike tire.

  6. Uk Road legal ebikes are terrible in their stock form. I got one from Halfords it was painfully slow and limited to about 15A peak at 24V. In practice more like 8-10A. Could not climb hills. I then bought a KT 36/48V controller and then set out to upgrade it. The Bikes 24V 4ah pack was current limited to only 15 A which I bypassed and then added a 30A car fuse inline with the negative wire internally. After this I took 2X 12v lidl powertool batteries and wired them in series with the original battery bringing up the system to 48V 4ah. Now it has a top speed of 40kmh on flat and about 18 uphill. The “250w” geared hub motor happily took almost 1kw with barely any extra heat. With throttle alone it was a 5 mile range. Could easily extend the range by building or buying a 48v pack with more in parallel.

    1. @Will – Hate to be “That Guy” but you should probably match the capacity and C rate of your batteries – bypassing the BMS (they’re on there for a reason) on the factory made bike battery and bodging it into 2 12v batteries in series? That’s making my bottom aperture wink like the mouth of an over oxygenated guppy fish.

      Also, the bike battery was a mere 24*4? 96Wh? Discharging at 15A that’s 360W at the motor and if it’s 96Wh something doesn’t add up. Saw you coming, most children’s hoverboards have better batteries than that.

      1. The thing is the bike was free (government scheme) so no loss for me only spent around £80 on the controller and batteries. I get where you are coming from but I have done calculations and everything is within the specs of the cells. The 13s2p pack in the bike itself is made up of cells that can handle 10A continuous discharge with 15A peak. We have 2 in parallel giving me a nice 20A continuous and 30A short peak. Similar story with the drill batteries. Remember these aren’t laptop cells those use a slightly different chemistry tjay allows for higher capacity at the expense of discharge rate. These can do atleast 10Acontinuous and 15A peak(I opened the packs and looked up the specs). The bike only pulls 1kw from a dead stop or going up a very steep hill which isn’t for more than 60-80 seconds in my case. Just cruising on flats it pulls approx 8/9 Amps (400-450 watts). Used a clamp meter to check. Batteries only get slightly warm and not hot. Also when it comes to charging all 3 batteries are charged separately so balancing isn’t an issue. The lcd controller has a LVC of 3.3v set so cells aren’t getting drained that far for some potentially weaker cells to get damaged.

  7. There is no such thing as a road legal ebike, legally they are motorcycles, require motorcycle license, motorcycle registration, motorcycle helmet, motorcycle insurance. Can’t drive on bike paths. 100% illegal under all circumstances in many places except your own property. You get into an accident and you are really really screwed, no insurance will cover you or the people and property that you hit. The signs that say No Motorized Vehicles, this means YOU.

    1. Here in the UK (and lots of other places) they are 100% legal, as long as they meet local regulations (15mph/250W). Might be an idea to do a little research before posting such hysterical nonsense as fact.

    2. In my (US) state ebikes ARE perfectly street legal and definitely *not* categorized as motorcycles. Scooters, up to 50cc, are also street legal and do not require a motorcycle license or helmet (since this state does not have a helmet law, even motorcycle riders are not required to wear a helmet).

    3. X,
      You must be the Karen that called the cops on me (disabled person) for taking my ebike trike on a bike trail. Cop told you their legal, sign said they’re legal, city council threw out your petition to make them illegal.

    4. Legal schmegal.

      You are posting on ‘hackaday’. Know your audience.

      Being illegal makes it BETTER and much more fun!
      Add a JATO to the bike, not we’re cooking with gas!

  8. > “The power assist should just cut out if you’re over 15mph – whether by your own effort or gravity – and back in again once you’re moving a bit slower.”

    I’m US-side in Kawliphornya. The above seems backwards. Up to 10mph for 5 mile distances, this septigenarian couch potato needs no assist. We have a law that makes these not exceed 20mph… and is why I never got one. IF they did 20 mph alone, it would be like a moped, w a 2HP limit. I dunno how THEY do the math, but that’s ~1.5Kw to me. If then I could add to that, shanks’ mare, and so do 30-35mph as a.cimbined result, I’d be interested. Speed is nice, blah blah, but really, we get bored waiting to get to where we’re wishing to find ourselves, when a 5 minute trip suddenly becomes 10, and then get the unplanned ice cream purchase, back home. I hope this is somehow does regeneration downhill, as a minor compensation.

    MY problem is a mom w a car full of 5 yr olds, stops, looks me in the eye, then turns in front of me as I’m doing 25-35 mph… and this brings to front part of the WHY. Bicycle brakes are fine for bikes, but wholly inadequate against the foibles of what we call, stoopid “cagers.”

  9. I remember looking at UK based biking youtube channel, more racing focused than commute, and during one of their endurance record breaking attempts they said, if I remember correctly, that a human produce around 400w on a bike. That lead me to guess that a 250w motor doubles the power output that I can achieve on a bike, giving me about 500w of power in total.

    1. The Watt rating on *almost* all electric bike hub motors is RMS or what the manufacturer deems safe continuous power through the motor. In practice a motor is exactly the amount of Watts you put into it. I currently ride a home-made (rear) hub motor driven bicycle with a 250W motor – powered by a 58.8Volt 24Ah 40A continuous / 120A instantaneous output battery. That will put my little 250W motor somewhere in the region of 7KW (peak) – with that setup it will only do about 30mph. My logic is that if I’m in traffic, I may as well be as fast as traffic. It’s important to remember horizontal rear dropouts and 203mm brake rotors are recommended! A final thought, the police will not bother you unless you’re riding like an idiot, we’re all responsible adults here, right?

    2. 400 Watts is for elite sportlers, a normal adult is below 150. That’s why people can climb hills with their 25 kilo e-bikes without breaking a sweat – 250 watts is *a lot*.

      1. Its all about how long as well as how hard – 400 Watt isn’t much for elite sport cyclist – depending on which cycling sport its either very low, or something like average. The sustained power output on the super long endurance road racers over a stage probably isn’t that close to 400W, but they will be hitting that ballpark and more for the uphill bits for prolonged periods…

        And 250w really isn’t that much, even the most unfit weedy but fully functional normal human adult should be able to peak around there and sustain it for a short time, anybody with some athleticism will find 200-250w something around sustainable, not an all day sort of output sustainable for most, but at least for a reasonably long time.

        As always HOW LONG you intend to stay at that power matters, as does how much effort you want to put in for this trip – no point cycling to work so hard you are too exhausted to stand at your machine tools all day for instance, and of course how you have been training – if you are all sprint athlete in how you exercise/train sustaining any load for long isn’t going to be easy as you will so rapidly build up lactic acid.

  10. I have been looking at recumbent trikes and was thinking of electrifying one.
    The whole point of bike riding is to get out and exercise.
    While the appeal of an electric trike sounds nice, a lot of Americans
    myself included are a bit on the heavy side. Hence, when the nice weather
    is around and you don’t have 2 feet of snow on the ground, (hey that rhymes)
    a nice bike ride burning calories will help a diet do its thing.
    Would I like an EBike with a 100 mile range? Sure, but then I’d still be
    fat and the purpose of riding is lost. I can easily pedal faster than
    25 mph, most people can, but trying to maintain that speed for 2, 3, even
    4 or greater hours on a day ride? Not going to happen. Even Lance Armstrong
    couldn’t do it. Hence, an electric can be a good thing.

    1. A friend of mine converted a Windspeed recumbent trike. The motor drove the chain, so it benefited from the gearing. He also mounted a 2’x4′ PV panel on top like a roof. It kept the sun and rain off, and provided power for the motor and battery charging.

      It was his daily commuter for a good 10 years. He could go as far as he wanted while the sun was shining. The only downside was that he had to park it “upside down” on windy days so the PV panel wouldn’t catch the wind it tip it over.

      PS: For picture of the kid’s EVs that I mentioned above, see on the Wayback machine.

    2. Bicycles are a great form of exercise, and I enjoyed riding. However, due to arthritis issues with my knees and hips, that is no longer possible. However, a bike with a 50 km range with no load on my knees / hips would provide me financially practical transportation independent of a poorly designed & undependable public transit system.

    3. Sorry to burst your bubble, but studies have shown that exercise does not help with weight loss. While exercise has numerous benefits, weight loss is not one of them. The only way to effectively loose weight is to control what you eat, the exercise myth is something pushed by food manufacturers as they want you to feel Ok about buying their products.

      1. I think what is more accurate to say is that research shows that physical activity *of the quantity generally recommended by the government* (21 minutes per day of moderate activity) does not *by itself* produce weight loss in *all* (or maybe even most–I didn’t check this) people:

        These qualifiers are important. For instance, it appears that quantities of exercise that significantly exceed the recommended minimums (60 minutes per day instead of just 21) do tend to result in weight loss. And while some people do not lose weight as a response to exercise, others do.

        A leading theory as to the difference appears to be that those who do not lose weight simply increase their caloric intake to compensate for the output. “Nonresponders to weight loss strategies demonstrated a much greater degree of hunger and subsequent food intake, which was sufficient in quantity to explain the weight differences.” If this is correct, then combining exercise with keeping caloric intake constant should produce weight loss more consistently. So, while exercise *alone* is not enough, that does not mean that exercise isn’t going to be a useful *part* of a weight loss program.

        If an Olympic swimmer eats 8000-10000 calories per day, it is hard to imagine that their weight wouldn’t balloon if they stopped exercise but kept the intake, or wouldn’t plummet if they took their intake down to the usual recommended 2500 calories but somehow continued the same level of activity (which I am assuming they couldn’t for long).

        Anecdotally speaking, I went from about 210lbs to 166lbs over 7 years while increasing physical activity to very high levels and somewhat decreasing intake (I normally eat very large dinners in an all-you-can-eat cafeteria; I describe my pathetic diet as “don’t pig out too much”).

        1. I lost 28lb in 6 months simply by changing my diet, mainly reducing sugar and not eating just because the food was there when I didn’t really need it. No change in physical activity. But yes, you are correct that most people feel hungry when increasing exercise and typically eat more.

      2. Better to say: Diet trumps exercise.

        Regular exercise raises your resting burn rate. There are direct weight loss benefits beyond calories burned riding.

        But if you pound on the butter after each ride? Wasting time.

        I suspect the studies you cite are theoretical. Just because people who spend hours per week exercising are going to trend healthy eating.
        Hard to tease the data into cause/effect. So they’d have to construct an artificial test group, fatties being whipped into exercise but also whipped into eating like pigs. 10 of them, study being run by diet book publishing company.

        Also: Cite?

        1. There is another issue with all diet and no exercise. Yes, weight loss needs to include appropriate caloric intake as compared to calories used. However, restricting intake means that the body may turn to other sources for energy, and it is easier to convert protein than fat. Unused muscle will be converted before fat. if muscle is being used, then they body will maintain it and consume fat. Accordingly, if one wants to “lose weight” without losing muscle mass, then one needs both dietary control and regular exercise, preferably whole body (or components summing to) exercise. Always balance and moderation.

  11. I’ve had electric bikes suggested to me numerous times… I run a radio station on my bike, and the last thing I need right next to a (relatively) sensitive shortwave radio transceiver is a noisy 300W 3-phase BLDC motor controller PWMing its guts out.

    In addition to this, motor + bicycle = motorcycle in my book; and motorcycles need an appropriate vehicle license — I lack any form of vehicle license. So no motor for me.

    1. If you are in the US, there is virtually no place where an electric bike is legally considered a motorized vehicle. They are considered “pedal assist” bicycles and can be ridden anywhere a normal bike can ride. Some states have power and speed restrictions, but not prohibitions or license requirements.

  12. May be just me, but I do not believe that “, and when you shouldn’t” should be anywhere near, never mind in the same phrase with “converting your to electric”

  13. I always feel like converting a bike to electric is a tragedy. It is such a beautiful, simple, elegant machine — why wreck it?

    On top of that, almost anyone is capable of making it go using their own muscle. And almost everyone would benefit from the exercise. I have been riding a bike and commuting on one all my life and can credit my health in many ways to the excellent exercise.

    Many people however, are lazy.

    1. I too have been commuting on a regular bike for years. But then I’ve moved just outside the city and have a 50m hill to climb. I can ride uphill, but it gets tedious, especially when carrying groceries or a child on a bike seat :)

      Similarly, my wife rides an ebike to the city. With a regular bike, she would take a bus instead.

      Not all people are simply lazy:)

    2. Because where I live there are hills. Big hills. My ebike means that I will cycle locally, and get some exercise, as opposed to none if taking the van (diesel) or the Vespa (2-stroke). The other objection I get from the pious is that it consumes fossil fuels; mine does not – it is charged via the 300W of PV panels on the garage roof.

      If I had a non-assisted bike I can guarantee you I would never ride it; arriving at my destination knackered and bathed in sweat isn’t something I consider desirable. Whether or not that makes me lazy by your metric, I couldn’t care less.

    3. Because I have a long term debilitating illness that without assistance I wouldn’t be able to cycle further than a mile or so?
      But by your logic I’m lazy.

        1. I’ve never seen anyone use the word “tyre” before. This is a first for me. Is tyre a colloquialism?

          n 1: hoop that covers a wheel; “automobile tires are usually made of rubber and filled with compressed air” [syn: tire, tyre]

  14. My dad once rode his electric bike to me, a 200km distance. He and my mother have the same bike, so he used batteries from both, and two chargers, rode 50 km, switched batteries, rode another 50 km, then had lunch somewhere charging both batteries at the same time (not full, but they weren’t empty) then did the same for the second half, arriving having just depleted his last battery about 2 km from my home (which was not the result of meticulous planning but just sheer luck)

  15. Well, I HAVE been lazy. Haven’t ridden a bike in about 5 years.
    A recumbent trike would be good for me to solve balance issues.
    I figure if I lose a few pounds in the bargain, that’s good enough for me.
    There’s a guy on youtube who is 80 years old and rides a recumbent.
    If I recall, his name is Dave. 80 years old and still out riding.
    I want to be doing that when I’m 150. :)

  16. I’ve done a couple of conversions, including building wheels around purchased hubs.
    Some things to consider: you’re probably limited to lower-power (sub-500W) motors on any conversion of an existing bike, because the motor is twisting the axle and you need to have some good way to react the torque into the frame. Some rely on rear wheel dropouts having rectangular sides, so the axle with the motor has flat faces that bear on the sides. These can wedge and damage the bike frame. Higher power ones sometimes come with a torque arm that also relies on those same flat axle faces, and again can end up with the axle twisting and damaging the frame. Plus, these all rely on the older road/mountain bike design of a 10mm rear axle. If you’re thinking about a conversion, make sure your bike has that: a lot of modern road bikes and almost all modern mountain bikes use through-axles, which are totally different and have round, not 10mm, holes in the frame for the axle, that can’t react any torque at all. They’re definitely unsuitable for hub motor conversion without a lot more work.
    People with electric-assist bikes appear to ride them about 3x as often as people with acoustic bikes, on average. They definitely appear to significantly encourage more bike riding, and for a lot of people they displace a significant amount of car usage.
    I don’t have one of my own (I’m still living under the delusion that I’m going to be a successful bike racer some day) but at some point I’ll build one to help with my 40km each way with 1km of hillclimbing commute to work.

  17. Make sure you go for a 48V system. The ‘250w’ motors will take it no problem. I can do 20MPH up hill no problem. I think it is best to convert an old bike that needs work and so saving it from landfill. I rebuilt my 25 year old bike with an eBay special kit. The old rear was damaged when the bike fell over in high winds. Also needed to replace a bottom bracket as the old one was shot. Bike is like new now. Very enjoyable building. Made use of my 3D printer to print brackets and some boxes. Really neat build with just two wires exposed, one to the handle bars and one to the rear wheel.

  18. Well, there are E-Bikes that can do 50 MPH or greater. Just search Youtube.
    You have people building bikes that can go 90-100+ MPH with battery capacities
    of 10,000 watts. Granted, on the plus side, having all that power is a good
    thing as you can ride for a long period of time and would be able to handle
    steep hills with no problem. If you want to be an idiot and weave around
    cars doing 50 in a 25 MPH zone, then when you are caught the book will be
    thrown at you….and everybody else. If you have such an E-Bike and ride
    responsibly, I don’t think anyone will care what power rating your motor
    is. It boils down to common sense and sadly, that is rare these days.
    I get people wanting as much power and battery capacity as possible.
    They want to increase the range they can ride using the motor only.
    As a person with less than 20/20 vision, I am unable to get a license
    to operate a motor vehicle, so an E-Bike with power and range would be a
    perfect fit for me. However as I said in a previous comment, I’m fat
    due to a sedintary lifestyle that has crept up on me the older I get.
    However, if I were to get an electric bike that has a greater wattage and
    power rating, that’s my business, and as long as I ride responsibly, shouldn’t
    concern anyone else. The commenter above who had the police called on him,
    I would have told the person, you know, there’s the sign saying the bike is legal. Read it, and mind your own damned business.

  19. Legislators need to learn to differentiate between power and how it can be used. Power (W, Ah) should not be used to limit speed of e-bikes. There are ICE powered cars and trucks that have difficulty getting from city speed to highway speed, and similar ICE vehicles that make the same speed change in 1-2 seconds. Similarly for hill climbing. High power vehicle operators who drive irresponsibly eventually get caught.
    E-bikes and operators should be treated the same way. If one wants to limit the speed of unregistered vehicles (where I live, a bicycle is considered a vehicle, albeit unregistered), then use an electronic speed governor on them, not a power limitation that limits range or the ability to climb hills.
    Registration: I rode from age 6 to well into my 40s (knee problems stopped that). That, walking and public transportation were my main means of transportation. I saw a lot of stupidity from cyclists. I felt then, and still now, that bicycles with rims over 16″ should be registered and plated, and operators over 12 years (past 12th birthday) should be trained and licensed, both through the local driver/vehicle registration system. Can’t fine / confine a person under 16 yrs? Make mommy & daddy responsible for locking up the bike for a period of time to teach jr some responsibility.
    As others have suggested: Assume the operator is responsible until they show they are not.

    1. Why 16″? Seems rather arbitrary, larger bikes tend to have larger wheels but the gearing is often different so the end result for the rider and speed is pretty much zip and as a tall guy I’d far rather have wheels bigger than that just so the bike is really comfortable to ride for me.

      1. Sorry, my initial description for registration was missing a bit. When I first began thinking about bike registrations, everything I had ever seen with wheels that size and smaller was single speed. I initially thought 20″ until I saw a big kid, oversize frame, 6 speed trying to rocket through pedestrian traffic. The intent was any rider past 12th birthday, and any rider of a bike that had to be registered, had to be licensed. Keep fees to cost recovery. From today, that first thought was about 45 years ago, things are more complex, and the idea needs a lot more work.
        This from the guy who figures that a held card reader slot (driver licence) & finger print reader to the left (for left hand drive vehicles) of the steering wheel of every car/truck would reduce a lot of problems. (theft, driving under suspension….) That, tho’ is a whole different issue.

  20. What sort of a motor does Swytch use?

    I’m pondering hacking up the kit I’ve ordered to also power the bicycle lights, and if the motor consumes AC, it’s going to be much easier (just a Y-splitter on the cable going to the motor).

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