Now that I am getting up there in age, I have become intrigued by e-bikes and how I might benefit from having one in my collection. I’ve read many reviews and test ridden a few e-bikes of late. Bikes with integrated systems that have a throttle and bikes that are purely pedal-assist. Some are direct drive with regenerative braking and others with geared motors that freewheel when coasting and don’t regenerate. There are many who love them and many who hate them. Then there are those of us somewhere in the middle. I think the biggest misconception regarding e-bikes and conversion kits is the notion that they will turn your bike into an electric motor-bike. So not true. What it does is it turns your pedal-only bike into a hybrid. That means it requires a shared input of your muscle power and power from the electric motor. It will not pull you up a hill. It will help you pedal up a hill. The more you help it, the longer your range. The more it helps you, the shorter your range. If you ride on level ground, you will probably get the range as advertised. If you ride steep inclines, you will not get the range as advertised. Simple, right? When we understand how these things work, then we can sort though the many e-bikes and conversion kits that are available and make the right choice for our own purposes.
There are kits and components that are of such high wattage (beyond the allowable lawful limits) that they will indeed pull the rider up a hill without any assistance. These components require lots of power and can drain a battery in minutes. Bigger battery, you say? Fine. More weight and more expense for a few more minutes. I am not interested in the unlimited category of electric cycles for there are, I’m sure, electric machines that can scorch a quarter mile track quicker than many internal combustion powered machines. I am more interested in kits that are street legal, widely available, and backed by the retailer.
The point of this discussion is to realize that there are limits. Limits to the application, limits to our equipment and limits to our pocketbooks.
A while back I had the opportunity to test ride the very expensive $7000 Specialized Turbo, pedal-assist e-bike. I was impressed by the ease with which I could pedal uphill and pass traffic. I felt like some sort of superman able to pedal at 28 mph with as little pedal force as I would exert on a casual ride with my wife. This was both exciting and terrifying as I realized that I could go very fast with little effort, while I would normally work harder to go slower on questionable terrain (for a bicycle). This became very evident to me after I had purchased the more affordable throttle-only, $1200 msrp, front wheel Currie Electric Kit-3 with a brushless geared hub motor for one of my MTB frames which I had converted some time ago to a simplified and easy to use, single speed, coaster braked cruiser. I had further refit this bike with 26x1.50 smooth tread Panaracer tires, which I keep inflated to the 85psi maximum for efficiency, front and rear v-brakes, lights and wider handlebars for better leverage. This simple, throttle only 500w and 36v kit can take you to 20mph on terrain you would normally be pedaling at around 5-8mph. Potholed asphalt and loose gravel get real dodgy on a rigid framed e-bike even at 10mph.
As I use this kit on this particular frame, I am learning more about my own limitations as a rider as well as the limitations of the components. I have learned to use the throttle-only system quite effectively. Instead of letting a “pedalec” system do the thinking for me, where the onboard computer meters power proportionally to pedal torque and/or cadence, I do this simply by applying just enough throttle to make my desired cadence and pedal pressure comfortable. Then often times I’ll let the throttle go to zero or turn the unit completely off while I continue riding until I need additional assistance. This becomes second nature and I have been able to travel 35+mi with lots of power remaining in the battery. I have yet to get caught with zero power with miles yet to go.
I can climb moderate inclines at a respectable speed around my hilly neighborhood without much sweat, climbing long grades that would normally be too exhausting for me to ascend. The sweating begins on the downhill ride, coasting with it switched off. At a blazing 35+ mph on a rigid framed, 80s vintage chromoly MTB bike with all that extra heavy electrical equipment, coaster brakes alone are woefully inadequate and things can get rather crazy very quickly. Luckily the fork has bosses for v-brakes as well as bosses on the rear stays. Front and rear v-brakes are the very least amount of stopping power one needs to be safe. Anything less would be too dangerous.
I’ve been using this bike traversing the foothills on errands and cruising yard sales with a friend in my neighborhood. Without the power assist I would not be cycling around this area at all. Unlike my stronger friend with his tricked-out Salsa and single wheeled trailer in tow, using the La Crescenta foothills as treadmills for his daily workout, I reserve my local rides to the occasional electric joyride. When we do ride together, the incompatibility is apparent. On an uphill trudge, he will be in a low, hill climbing gear, slow but steady without the cares of running out of power, while my electric wheel needs more rpm to keep from bogging and draining the battery. Thus, our two rates of speed become incongruous with one another. This is mostly due to having only one gear and depending on the electric motor to compensate. So, I speed ahead to relieve my motor of the strain and heat build-up and wait for him at the top. I have tried to power-pedal up steep grades without electrical help, but the single speed gearing is too high to have the mechanical advantage for forward motion therefore impossible for me to accomplish. With that said, this configuration seems a good match because for the most part the motor negates the need for gears; it can carry a light load on the rear rack with side baskets, bike bucket or panniers and allows me to sprint up the final steep hill to my house (providing I have at least ¼ battery capacity left) and requires little to no maintenance.
This is the first of what will be many configurations before I am ready for other kits. The obvious next step was to put this kit on another bike with a multi-geared drive train, so I put it on an older 18-speed MTB and got better performance with the ability to use the “granny gear” with very little throttle input. My range is still great and the ride is very stable and comfortable. The thing is that, I have been hauling “stuff” on the rear rack using panniers and baskets. I’ve noticed the load makes the rear part of the bike very whippy or overly flexible.
My only option now is to design and build a lightweight cargo bike that will perform well with this particular kit.
I considered a cycle truck configuration but my kit is a 26” front wheel model and a cycle truck uses a small front wheel to keep the load lower in a deep basket, rigid to the frame not the fork.
After making a few sketches, I decided to go with a long-tail, rear loader design based on a Peugeot mixte frame. I made a list of necessary features I found to be obvious. Lateral rigidity, low center of gravity for the cargo section, low cost to make, low maintenance and low cross tube design to help the rider control a heavier than usual bike.
I gathered components and elements to pre-visualize the overall shape and structure and laid them out on a full-size drawing. For days I would arrange and rearrange these elements, solving logistical problems and testing out each solution in my mind.
I have found this to be the most effective way to achieve the intentions of my mind’s eye when using only scrap parts and materials from previous projects. So much of even the most unusable bit and scrap sometimes becomes the solution to a design conundrum. Therefore, I never throw anything away and have accumulated several boxes of scrap metal of all shapes and sizes. A curved section here, an odd shaped piece there, or the tiniest of trim piece, usually rescues me from having to create much needed gussets, braces, extensions or details needed to make a design come together. Even though my bikes might be considered Frankenbikes, they don’t look like they are made of several bikes mashed together. Instead they look like unique production builds. It is only when I point out to someone that I used cut up fork sections for a chainstay and headtube brace, that they see it. And even then, some still have difficulty seeing the ‘Franken-ness’ in my approach. That is the payoff of pre-visualization and thinking things through. It is also a luxury to build non-commercially without regard to anyone else's vision except my own.
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Head tube extension to raise the front and keep fork angle correct.
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Finally I reached the point at which I started to fabricate. As I used only recycled and repurposed materials, I knew this prototype would get a bit heavier than an ideal scenario of ‘super light Reynolds double or triple butted, drawn over mandrel, custom made to length tubing’ that could cost more for one seat stay than I spent on the entire frame. I’ll leave that kind of obsession to the artisan that makes multiple frame sets at $5000 a pop. I am only interested in prototyping my own concepts. Any version of my designs or prototypes that are made lighter can only be an improvement.
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| Another jig-less build. |
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Making sure the bottom bracket height is sufficient.
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A temporary axle is used to keep the dropout width within specifications.
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Soon, it all came together and a new configuration was born.
I have tested this bike out quite extensively and found I get 30mi+ range while carrying all my stuff and then some.
Good gear range and simplicity makes the Nexus 7-speed internally-geared rear wheel the most important component for reliability. Front and rear v-brakes (I swear by them) allow me to have absolute control and stopping power. Fenders front and rear allow me and my cargo to stay clean on wet or dry pavement. Comfortable riding position reduces fatigue and allows me to ride long hauls. Versatile cargo station allows for baskets, panniers and boxes all on the same load. A heavy-duty center stand keeps the entire package rock solid while loading and unloading and a spring stabilizer at the fork keeps the front wheel from flopping from one side to another while elevated.
All this on a cargo bike makes the riding experience very pleasant. It doesn’t feel heavy, awkward or unstable. Instead, it’s fast, tight, light and nimble. One of my favorite designs to date.
There are smaller, lighter, less expensive kits but they cannot do the job required for my use. They might be good for someone with bad knees who still wants to get out there and ride or a commuter who uses a bike for transportation on relatively flat terrain and needs just a little help to justify not using their car and get to their destination without being drenched in sweat.
As you research and explore an electric option for yourself, you will soon realize that the quality of the kit is essential and a battery of sufficient size and capacity will be the most costly and heavy component. I do not need an electric kit to enjoy bike riding, but if I plan to ride up hills for errands in my neighborhood without feeling like I’m about to have a stroke, then this kit is working for me.
P.S.
Now that I’ve been an owner of an e-bike kit for almost two years, I have come to a rather disappointing conclusion about them. Most kits have limited warrantees on them due to the fact that many of the lithium batteries used are only good for two (my case) to four years or max number of charge cycles which ever comes first, until the chemicals within go bad and render the battery useless and become toxic waste that needs to be dealt with properly. So for another $800 (again my case) to $2000 or more, you must purchase another battery pack to keep your e-bike an e-bike. For a couple of hundred dollars less, you could hack the battery pack and replace the cells yourself, if you know what you are doing. Or find someone to do it for you and you’re back up to spending retail again. Not to mention the motor itself. Plastic, composite or nylon gears are used because they don’t require lubrication as they are considered self-lubricating. But they will wear out eventually and require some service. Relatively inexpensive compared to batteries. Some would-be hotrodders will use these motors in conjunction with higher voltage power supplies to get more speed but soon find out that higher speeds equal more friction and heat, wearing out the gears sooner and turning the gears into a mass of “plastic peanut butter”. But I digress.
Imagine any regular bike with a shelf-life causing you to reinvest hundreds or thousands of dollars every two to four years (whether you ride it or not) just to keep it a ‘bike’. You probably wouldn't own one. I certainly wouldn’t.
Although as time goes by, battery technology continues to advance and prices fall a bit still, companies that produce these kits and e-bikes need to either have a buy back or trade-in program for batteries because many of us now, and many to follow, will have a very rude awakening. I for one, cannot recommend ownership of an e-bike. The battery technology is too expensive and too temporary. Instead, just rent an e-bike for the thrill of it because they are a lot of fun.
Then walk away.
I designed it for that eventuality.
KG
