A word of warning. I started looking a little into motor assist bike mods a few years ago, and very quickly you find that the biggest mistake people make in this area is not altering any of the other systems of the bike. That is, they'll put in the motor, and then just ride. Which works, but then you find that your brakes aren't quite good enough to stop quickly at the new higher speeds. Shocks are no longer good enough to prevent certain issues as well. Maybe the frame needs reinforcing... I don't quite remember the whole laundry list.<p>I don't know how important some of these improvements are, I just remember reading this advice more than once, and safety is important. So be smart and do your research.
Before you get on one of these, it’s good to check your perspective on safety: <a href="https://youtu.be/wM8Xli2KTzI" rel="nofollow">https://youtu.be/wM8Xli2KTzI</a><p>As a motorcyclist, electric bicycles make me very nervous.
If you are serious about diy ebike be sure to check out these two links:
<a href="https://endless-sphere.com/forums/viewforum.php?f=21" rel="nofollow">https://endless-sphere.com/forums/viewforum.php?f=21</a><p><a href="http://ebikes.ca" rel="nofollow">http://ebikes.ca</a>
It's a shame the Copenhagen Wheel never went anywhere. It looked so promising.<p><a href="https://en.wikipedia.org/wiki/Copenhagen_Wheel" rel="nofollow">https://en.wikipedia.org/wiki/Copenhagen_Wheel</a>
Perhaps mod this into an airline-compatible e-bike?<p>Airlines which will happy carry a <i>non-motorized</i> bicycle as a standard checked bag, won't touch a motorized bicycle at all.<p>So a conversion which can be easily and unambiguously removed, might leave you with a checkable non-motorized bicycle, and unrelated, a small motor, some electronics, and perhaps a TSA-compatible small battery. Then add say a commonplace "portable power station" battery shipped to/bought at your destination.
If you don't want to be permanently tinkering, there's a whole range of e-bike conversion kits which work well.<p>I've got a Tongsheng TSDZ2. You remove the pedals and chainring and slot it in place, and your bike is electric. It's got built in torque sensors so pedalling is amplified - a very natural feeling. There's a range of similar motors made by a company called Bafang (BBS02, BBSHD) which generate more power and are more robust, but don't have torque sensing. For a bike in the EU, where you don't really want more than 250-300W anyway, the TSDZ2 is fine.<p>There's cheaper kits which use hub motors. Often you get the wheel pre-built so you just remove your existing wheel and insert the one with the motor.<p>The bike conversion kit is fairly straightforward if you're mechanically minded / have done any bike maintenance before. Sourcing a battery is actually the hard part - good batteries are expensive, and shipping from China is complicated. Once you have the battery it mounts where a water bottle would go. Mounting the kit and wiring everything up took an afternoon.<p>All in, the equipment cost me around £500. I already had the bike.<p>[1]: <a href="https://ebikechoices.com/tongsheng-tsdz2-review/" rel="nofollow">https://ebikechoices.com/tongsheng-tsdz2-review/</a>
> <i>The approach I adopted is mechanically as simple as you can get. It uses an "outrunner" motor designed for electric skateboards. With such outrunners, the case of the motor rotates. Driving the bike with it merely requires mounting it to the frame in such a way that the case is in contact with the rear wheel.</i><p>I haven't crunched the numbers, but this[0] Low Tech Magazine article from 2011 about the reverse process (generating electricity with stationary bikes) gives me the impression this adds quite a bit of inefficiency to this set-up:<p>> <i>One reason [for inefficiencies] is the use of a so-called friction drive - the rear bicycle wheel acts upon the small roller of the motor/generator. While chain and belt drives (used in late 19th century pedal powered machines) have an efficiency of up to 98 percent, a friction drive is only 80 to 90 percent efficient (and wears much faster).</i><p>Whether or not you think that this is important is a different discussion of course, but I think 10-20% less range is quite significant.<p>[0] <a href="https://www.lowtechmagazine.com/2011/05/bike-powered-electricity-generators.html" rel="nofollow">https://www.lowtechmagazine.com/2011/05/bike-powered-electri...</a>
In Germany you'll need a speed limitation on such a construction (25 or 20 kmh, I think). And it must only assist pedalling, never drive the bike on its own. Otherwise this will count as a motorized vehicle and must be registered accordingly and needs vehicle insuramce. Don't know how hard it is to get it admitted for street use.<p>I'd love to see a minimal setup for these requirements :) Does anyone know of something?
> The lack of noise, combined with the discreet positioning of the motor and other components, makes it hard for anyone to notice that I'm on an e-bike.<p>Sorry, buddy, but in your dreams only. It is blatantly obvious for anyone if you are riding on your own, or if you have assistance - your body position is different, the power exerted looks different, not even mentioning the battery pack on your back wheel, and the motor behind your bottom bracket. So "OK Boomer" indeed.<p>On the other hand the real problem is that people who cannot really ride bikes now get easy access to speed. I regularly see them on my daily commute here in Vienna, where - despite the 25kph limit - these boomers ride in a way that scares the hell out of me. They go fast when they shouldn't (combined bike paths with lots of pedestrians), go slow when they don't have to (downhill), and generally are visibly uncomfortable on a bicycle.<p>I cannot imagine what would happen if you took an elderly person with an old bicycle and converted said bicycle using an unrestricted motor... that's really just asking for trouble.<p>I mean, people can be generally stupid - just last week a 78 year old driving a moped (!) was caught on the motorway driving in the wrong direction (!!!) in the inside lane (!!!!!) for a few km's before police caught him. And he wasn't even drunk.<p>Perhaps the solution is to introduce a driving licence category for e-bikes. And if they are unrestricted then they should be banned from cycle paths too.
It would be quite interesting to see how these “tire contact” motors will perform once it starts raining or your tires get really dirty.<p>I think there is a reason, why crank or hub located motors are the norm now.
> I was able to come up with an e-bike conversion that cost me less than US $200 and yet functions impressively.<p>... excluding the cost of the battery. The battery costs $150 in HomeDepot
Very interesting. I would love to see a video where someone does it from start to finish.<p>I would also like to make my own battery for the bike. I made a cheap DIY spot-welder from a microwave transformer and spot-welded my first 12V 20 Ah battery last week for a 3d printed robot lawn-mower project.
That's a great hack. But I'm a big guy, bordering on 285lbs. That kind of low power traction doesn't seem enough to move me. I know European 250w motors are never enough for me.<p>I've build my first ebike a few months ago. I went for a 1000w Bafang mid drive geared motor with a 48v 20a battery, on an old used Peugeot mountain bike. Adding some new/used bike parts (wheels, tires, chain and rear gear), total project cost arrived at C$1800, less than half the price of a new ebike with similar specs.<p>Considering my weight, 20 to 23 kph is my speed of choice in pedal assist mode, which is quite safe. It does extends my range a lot compared to other use cases.
Here is my tutorial to de-car (unfortunately in Swedish but google translated): <a href="https://translate.google.com/translate?sl=auto&tl=en&u=elhjul.se" rel="nofollow">https://translate.google.com/translate?sl=auto&tl=en&u=elhju...</a><p>The biggest issue remaining is the wear of tires, and no good alternatives really exist for bike rims in terms of thicker tires.
Calculating the battery as given feels a bit like cheating for the 200$ number: A cursory search on Amazon puts the cheapest battery at 100€ and most in the 300€ range. Quite unfortunate, as I had hoped the author found a cheap option.
"cheap" and "ebike" don't really belong together.<p>A cheap bicycle is extremely dangerous, so a much faster cheap bicycle is crazy.
cyclone have been selling cheap conversion kits for around US$300 since at least 2005 <a href="https://web.archive.org/web/20061212021226/http://cyclone-tw.com/newkits.htm" rel="nofollow">https://web.archive.org/web/20061212021226/http://cyclone-tw...</a>
400 Euros is all it takes for a 500W battery, 500W+ direct drive motor E-Bike conversion.<p>200 Euros just for the battery pack. And we're not talking some shit 7Ah pack that will last half an hour. An hour at full power is the minimum, anything else is unacceptable.<p>Whether used for constant speed, acceleration only or pedal assist, what's the point of an E-Bike that's deadweight after less than an hour?<p>I actually have made a design using a 1KW brushed motor that replaces the pedals and uses the hub gear. It is cheaper, but harder to install (needs at least a custom frame for the motor) and is illegal on bike lanes as the pedals are removed. Could share it if anyone cares.
I like nerds but man is it out of touch/socially awkward to posture based on how often you use the front brake and link to a decades old blog post doing the same.