# Ebikes, a breakdown [[2025-06-19]] _Disclaimer: Most of the comparisons I make are certerus paribus but there are lots of ways to put together an ebike and too many variables to state anything with strong conviction. ## Executive summary: - The right ebike is really determined by your use case. - The key factors in no particular order (outside of normal bike factors, like types and size): - Top speed wanted - Range - Hill climbing ability - Weight - Cost - Utility (racks, panniers, etc) - Factory vs Conversion - Factory bikes tend to be more expensive, but better integrated and design as ebikes. Easier to get serviced too. - Conversion tend to be less expensive, have more options in terms of power delivery, but need more fiddling to get setup right. - Motors are typically: Hub motors or mid-drive (at the pedals) - Hub: easier conversion, cheaper, less powerful and worse on hills. - Mid-drive: more expensive, heavier, more powerful, more of a 'seamless' experience. - Electrical section (feel free to ingore...) - Voltage matters (36-52v and up) - Care and feeding of your battery - Match voltage! - If you're cold, they're cold. Don't charge them in the cold! ## My choices vs your choices I like tinkering and building things. Since my motorcycle and cars are all reliable these days, I fell back into tinkering with bikes. It's meditative for me, and I have an aversion to paying someone to work on my vehicles for me (although I'm learning to let go a little). My criteria, at the time, was to build something robust, Scott-servicable, and a little more than what I needed. There may have been some scope creep during my design phase... At the end of the day, in 2021 the best value for money was an old mountain bike style frame I had laying around, and a heavy duty mid-drive motor with a sizeable battery in case I wanted to ride 50+ miles. It was the pandemic, who knew if we were at the start of an apocalypse movie? Better to have range and not need it. I wanted a bombproof, fairly quick, adaptable bike-as-transport option, where I could run errands and get groceries, or take a big picnic to the park and decide to do some shopping on the way home without wearing a backpack. The bikes are amazing to ride. Just so much fun and all the worst parts about cycling (except the car drivers) is reduced. But they aren't light. I didn't go for a lightweight build, and it shows. I can just about get my normal ebike onto a rack without looking too worn out, my cargo bike is a two person job, at least. But I don't use bike racks often (maybe twice in 5 years?), so weight wasn't much of a consideration. I also spent some time learning how to program the settings so I could fine-tune the ebike's power and response for my preferences. There was some trial and error, but it was more tinkering so it kept me out of trouble. After looking at the used market and comparing prices, I would probably not build a conversion today except as a hobby in an of itself. There are some *really* nice ebikes on the used market for not much more money than a conversion + new acoustic bike. ## A series of binary choices I'm going to breakdown the ebike choice into a series of (mostly) binary choices. Some of these are parallel choices, where your choice doesn't necessarily limit your other choices, where others are sequential choices, one choice leads to another. ## 1. Who made it? Factory vs Kit **Suggested Choice: Used Factory Bike** There are a ton of factory ebikes these days, far more than were available when I started building my bikes. There are a lot of benefits to a factory ebike: #### Pros to a factory bike 1. Service and support 1. Brands like trek, cannondale, REI etc. use good components, have warranties, generally offer good parts support for several years. For example you can buy batteries or get your motor fixed if there's a problem. 2. They can and will be worked on by most decent shops (REI in particular) 2. Designed as an ebike often mean better aesthetics 1. Good factory ebikes are designed from the ground up to be an ebike (this can be a double edged sword, more on that later). 2. Integrated batteries and controllers mean the system is 'turn key' and as easy as it gets. 3. No tinkering needed. #### Cons 1. Price. 1. Per dollar spent, you often get less capability and fewer options. The capability issue only matters if you need the capability in the first place. In truth, most people don't need the full capability that can be provided with a kit. 2. For example, a $1700 ebike will not be in the same class of power, range and flexibility as a $1500 kit. (But a $4000 ebike marked down to $2000 can be a great deal). 2. Lock in 1. Factory ebikes use propriatary batteries and screens and other components that mean you have to go to them for parts and those can be at a premium or not available after a few years. 2. (Counterpoint) There are a lot of people in the ebike world who are finding ways to repurpose or create diy-fixes for unsupported hardware. 3. Custom programming is impossible 1. With a kit, you can custom program the power options and delivery from the motor. Typically impossible with a factory bike (this is part of the tinkering that I like to have access to, but I understand that it's not for everyone) ### Kit Pros 1. Value for dollar spent. 1. For $1300-$1500 I have a bike that is as capable or more so than bikes costing $4k plus. 2. Ease of service and parts. 1. Because the parts I use are used in thousands and thousands of other kits, I can order parts, or replace batteries without being locked into a particular vendor. 3. Custom settings 1. I can tune the ebike to provide me the exact ride experience I want and is most comfortable for my fitness/riding style. 1. For example, I keep the speed limit to 25mph for safety but have 9 settings from no help at all, to lots of power and torque when I'm running errands on a time limit. 4. Great base bike and the ability to move it to another bike in the future 1. My base bike is a nice light hybrid which helps keep total weight down. If I get another bike in the future (or this bike gets damaged) I can move the motor/battery to that new bike so I only need to buy the kit once. ### Kit Cons 1. A DIY approach has it's drawbacks (for many people). They need to be built, tuned and then if anything goes wrong, **many shops won't work on a converion ebike.** Especially on any of the electric drive-train components. 2. Expensive & heavy, even if you have more flexibility than a factory bike. The kit and battery weighs almost as much as the bike itself. 3. Aesthetically lacking. Kit bikes almost always look a little funky, with wires running outside the frame, and a battery pack strapped to the frame. 4. Low resale value. Used conversions are not easy to sell, as there are many many bad conversions out there. So the choice between a kit bike and a factory bike isn't clear cut. 5 years ago, it was harder to find good factory ebikes that weren't $5k+, but even the major builders have options in the sub $3k range now. With the explosion of ebikes in the last 5 years, and so many people bought ebikes during the pandemic, but didn't use them, there are lots of decent barely used bikes on the used market these days. ---- ## 2. How the bike is powered: Wheel hub motors vs "Mid-Drive" motors **Suggested Choice: Mid-Drive** _A brief explanation of electric motors: Electric motors and gas engines like certain rpms (revolutions per minute). Gas engines have a broader range of 'good rpms' but they still need a gearbox to be effecive from 0-mph to freeway speeds and above. Electric motors are less flexible and they really want to spin at their ideal rpm. Power and torque drop off pretty fast outside that ideal._ Most factory bikes less than $4k are wheel hub type bikes. This means the motor lives in the rear wheel and comes on when you pedal. Simple and inexpensive, but also limited in terms of total power and the electric motor doesn't get the benefit of the gears. Kits for wheel hub motors are also significantly cheaper than mid-drive kits. The two big downsides to wheel hub bikes are: 1. The wheel motor creates resistance when the battery runs out or if the motor is off. It will never pedal just like an 'analogue' bike. 2. Wheel hubs don't have the benefit of the gear box to keep them at their ideal rpm, so hub motors typically don't have the range of speed and power that mid-drive motors do. 3. (Smaller downside): Changing the tire/tube on a hub drive bike can be a pain, due to the wiring that goes to the wheel. I already hate having to deal with flats as it is, and having to wrestle with fragile wiring in addition to everything else is something I wanted to avoid on my bikes. Mid-drive bikes are the most expensive option but they put a motor at the pedals. This means the boost from the motor can take advantage of the gear cluster and stay closer to their ideal rpms, providing efficient power and torque at low speeds (up hills) and obtain higher speeds. They also tend to be better at heat dispersion, so theorhetically they will last longer. Heat build up is what kills electric motors. Water. Water also kills electric motors, but well designed ebike motors are typically ok with some rain. Mid drives aren't limited to the space inside the wheel so they can be more powerful (most wheel hubs are limited to 250w these days) and have more torque which are both useful in dealing with hills and heavier loads. However mid-drive motors tend to be heavier than hub motors. For kits there are lots of options in both types of motors. I prefer the Bafang BBS-HD, a mid-drive 'heavy duty' 1000w motor. They've made millions of these are they are generally regarded as the best value basic mid-drive option. It is the ford f-150 or toyota camry of kit motors, but it's 14lbs all in for the motor. There is a lighter option that's a little more refined but also a little more expensive. It's about 1/3 lighter and also has torque sensing, which the Bafang doesn't offer. ## 3. What makes the motor go: Sensors, cadence or torque sensing (+throttle) **Suggested Choice: Torque Sensing and no throttle** _(full disclosure, I don't have a torque sensing bike, but I hear nothing but raves about the experience on a good one)_ Torque sensing is more common in mid-drive motors, but not universal. This is the trigger technology for the motor to begin assiting your pedaling. Torque sensing is the 'premium' choice. Basically the motor can sense how *hard* you are pedalling and assists based on pre-set values. So if you want a harder workout, you set it low, and once your legs are pushing a certain amount on the pedals, it ramps up the assist with the goal that your effort remains consistent. Cadence sensing is based on how fast your are spinning the pedals. The actual effort applied to the pedals isn't measured. With a kit motor, there is a wide variety of setting you can use to adjust your experience. From small amounts of assist at low pedal speed, or giving max assist once you reach a certain cadence or reversing that, so it gives max assist to start and then tapers off once you reach your prefered cadence. Personally I use a mix. At low to medium cadence I ramp up the assist pretty quickly. My comfortable pedalling cadence is between 75-90rpm, so once I reach that point I have it dial back the assist to moderate levels so I get a workout but I'm still covering ground quickly. Cadence sensing allows for 'ghost pedaling', where it provides assist when you're barely pedaling at all. For example, if I'm trucking along at 20mph and putting effort into the pedal with a mix of assist and pedal power, if I back off so I'm slowly 'freewheeling' the pedals the motor picks up more of the workload and I can maintain maximum speed with barely any effort at all. When I'm out for errands or not specifically a workout ride, I find that I will pedal with moderate effort for a while (5-10m) then give my legs a little break for a couple of minutes by slowly freewheeling the pedals, then give another 5-10m of effort. The bike maintains 15-20mph the whole time regardless of my effort. With both types, the pedals must be moving for the motor to turn on. #### Throttle: Not worth it Most kits have the option for a throttle addition to the kit. This is a little thumb lever that turns on the motor without input from the pedals. I have them on my bikes, but I've unplugged them as I find them more trouble then they are worth. They can get sticky and cause problems with the bike wanting to ride way on it's own. My bikes live outside, so that's probably contributed to the sticky throttle problems. Also, bike trails and paths are increasingly banning ebikes with throttles. # Electrical Stuff (Bonus section) - Batteries - Voltage - Chargers - Battery health - Motors - Volts - Watts Without going into depth on electrical concepts like volts vs amps vs watts, here are some things to consider with ebikes. This is simplified for practical purposes and personal limitations. Electrical stuff has always been my weakest subject in the DIY space. I know enough to be minimally useful. ## Batteries There are a lot of battery options out there. The key characteristics is size, cell quality, and build quality. Cheap lithium batteries (amazon specials) can be problematic and dangerous. The news is rife with lithium battery fires, and the vast majority of those are because they are cheap, poorly made and abused (improperly charged, stored or otherwise damaged before the fire). Still, for peace of mind I try to buy quality batteries, and charge them only while I'm home. Much of what you probably learned about your camper solar system applies to ebikes. Although ebikes do not tend to use the better, more robust Lithium Iron Phosphate (LiFePo) that have become common in the camper world. ### Voltage Batteries tend to be described using several key specs: Voltage and amp-hours. Voltage is essentially how powerful the battery will be, and amp-hours is how long it will last. You want to match the voltage to the motor, and the charger needs to match the battery. A 36 volt motor should have a 36v battery and 36v charger. Amp-hours (aH) are typically bewteen 10-20. A 10aH battery is fairly small and can fit in a large seat bag. 13-18ah are the most typical size batteries, and most often are bolted to the downtube. The most common voltage for kits is 48 or 52 volts as it's the best in terms of performace/cost/size of battery per ah. Older ebikes and some factory ebikes are 36v as they tend to be less expensive, but it's a standard that's falling out of favor. For the record there are 70v high performance options but thats a different use case and tends to get very pricey. I recommend 52v for kits, but 48v is just about as good. Factory bikes still tend to be 36v, which is fine. ### Chargers A well made battery deserves a well made charger. Chargers need to match the voltage, and the better chargers allow for setting the amp limit (i.e. how fast it charges and slower = better in the long term), as well as the max charge (80%-100%). For a kit setup, buying a charger is yet another part of the cost. Many batteries will come with a charger, but they often don't have the ability to change the amperage or charge level. My standard practice is: When the weather starts to get nicer, I will charge my batteries up to 80% while I'm home. My day to day riding (running errands in my neighborhood, getting a cup of coffee) typically only depletes my battery 10% or so. I'll keep running it until I get to 30-40% before I charge it again. If I'm planning a longer ride, I'll charge them to 100% the night before. After my ride, I'll charge them back to 80%. ### Battery health Also batteries should not be charged when it's cold! Charging a lithium battery when it's 45f or less can damage them. Not a big problem in California, but worth noting especially in the winter. Lithium batteries can hold a charge for a long long time. I often only see a drop of a couple of % points after months of storage. #### Charging Level Lithium batteries don't like being charged to 100% all the time. For max battery life, or if the bike isn't going to be used in the next day or so it's recommended to only charge to 80% and discharge to 20%. _NOTE: This caution is probably unnecessary. A good lithum battery can be charged 500-1000 times, which means years of life if you are commuting on a daily basis._ #### Charging Amps Amps are essentially how fast energy is given to the battery. 1 amp is pretty gentle and slow. Most usb chargers for devices are 1-3 amps, for example. Over 3amps is pretty fast (especially at 52v) and suitable only for quick charging and shouldn't be used every time. The more amps, the more heat that is generated, and heat during charging is often what degrades a battery. Excessive heat inside the battery pack can cause a catastrophic failure and perhaps a fire. I tend to be overly cautious about the risk, but I rarely need to quick charge my ebike, so I just avoid the issue. It can take a long time to charge a large battery pack at 1 amp, however. Especially if it's at 20%, as in a day or more. I've settled on a 2a rate to 80% most of the time but your use may vary./ ## Motors #### Voltage 36-52V are the standard voltages across most of the ebike spectrum. I've settled on 52v for my standard, but 48v is valid as well. Factory bikes tend towards 36v. Higher voltage tends to be more effecient in terms of power per weight and volume of motor and battery. A 52v motor and battery will get more power and range for a given weight and size than an identical setup at 36v. The difference can help you compare kits and bikes. The higher the voltage, the more energy 'dense' the system is. We aren't racing so 36v is fine. I bought 52v because there was a bit of a voltage-war going on in the industry when I first started researching, so I splurged for 52v thinking I was future-proofing myself in case 36v stopped being support. Years later, 36v is still the standard for factory bikes. #### Watts Motor 'power' is often listed in terms of watts, where 250w is the typical minimum*. 500-1000w is a pretty normal range for many kit motors. Most factory bikes say 250w because that's the legal limit in places in Europe, but when tested they often put out significantly more wattage. So wattage ratings are a guideline _at best_ when comparing bikes and kits. In truth, the wattage doesn't matter that much for most people. If you were climbing Divisidero every day on your commute, it would be worth looking more closely at wattage. The issue is that ebikes are often more powerful than they need to be, especially if you actually like cycling. There's a vocal segment of the kit market that is more interested in building electric motorcycles in a bicycle frame, then building an efficient, right-sized system. _Note: yes, my kit motors are both rated for 1000w and peak at something like 1500w, but I actually purchased the "Heavy Duty" version because the bearing & case design was better than the standard version of the motor. I think I've detuned all my motors to 800w or less._ ## Conclusions Whew. Ok if you read this far, congrats. I _hope_ this has been helpful, but I also recognize it's a LOT. Here are my two recommendations: 1. Used factory ebike from a major manufacturer using one of the "big 3" mid-drive motors from Bosch, Yamaha or Shimano (in that order). 1. Disc brakes 2. Fender/racks are a bonus. 3. As lightweight as you can find 4. removable batteries are a plus (better future proofing too). 2. Convert your CTY 1. Mid-drive motor and minimal battery to help keep weight down (13ah or less) 1. Bafang BBS-02 (NOT the HD) motor 2. CYC Photon (when it's available again) 1. Lighter 2. Very good torque Sensing 3. 48v battery, ideally UL listed (hard to find) 2. Hub motor and minimal battery 1. Bafang is still a good choice in hub motors. 1. 500w rear wheel option 2. 48v battery. # Sources: ## Retailers - https://www.johnnynerdout.com/ - https://california-ebike.com/ - https://www.ebikessentials.com/ - https://lunacycle.com/