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Tesla Bike
- Thread starter krt72012
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- bike commute commuting motorcycle
Not looking.
Shouldn't touch bikes. We need electric bikes to be cheap, not label and boutique.
Shouldn't touch bikes. We need electric bikes to be cheap, not label and boutique.
What if a better bike is needed to get people to shift from cars to biking and be comfortable? Many drivers are hesitant to bike especially in non west coast cities. A bike that costs $4000 and uses much less energy would beat out a $35000 car no?
mspohr
Well-Known Member
I just converted our two bikes to electric for less than $500. I don't understand why people spend $4000 on an electric bike... must be a status or fashion thing.
I'm not concerned about people deciding between a $35k car and a $4k bicycle. I'm concerned about people using a bike when they can and an alternative when they can't.
A $4k bike sn't going to cause the kind of acceleration of sustainable transportation that Tesla has as its mission. It's the cheap Chinese e bikes (but better) that would make the real difference.
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There are some very, very nice e bikes for $4k, just as there are some very nice non e-bikes for thousands. I don't think it's fashion, it just another high quality item owned by people who can afford it. But they own them in addition to cars, or they own them because they live in a city where their residence is insanely expensive and owning a car is a massive pain.
bhtooefr
Active Member
This concept comes off as impractical design porn to me.
That said, Musk has said that a bicycle is possible: Full Q&A: Tesla and SpaceX CEO Elon Musk on Recode Decode
That said, Musk has said that a bicycle is possible: Full Q&A: Tesla and SpaceX CEO Elon Musk on Recode Decode
mspohr
Well-Known Member
The problem in the US is not enough bikes. China, OTOH, has too many.
Would avoid this:
But is this what Elon is trying to solve?
bhtooefr
Active Member
Gonna bump this thread, because I'm curious if there's been any progress on this front (I can't find anything, though, which makes me think there hasn't been anything).
So, there's quite a few players in the e-bike space currently, and it's even to the point where in the Netherlands, e-bikes now outsell all other types of adult bicycle combined. Tesla tends to shy away from markets that are already electrifying successfully.
However, I see room for massive improvement in the motor and control systems on e-bikes, that Tesla is fairly uniquely positioned to do.
There's approximately three markets that I see in the e-bike market.
The first market is the low-end market. In most of the world (Japan is a huge exception, I'll cover them separately), this is dominated by Chinese manufacturers, typically using off-the-shelf hub motors paired with off-the-shelf controllers and batteries. Direct-drive hub motors have fallen out of favor due to the high weight and poor efficiency (low RPM isn't good for efficiency), with geared hub motors taking over. All of these motors are either surface permanent magnet, or a very primitive form of interior permanent magnet with insignificant potential for reluctance torque, combined with relatively thick laminations to reduce cost, meaning that there's significant cogging/iron losses at reduced power levels. As this gets worse as you increase RPM, geared hub motors almost always have freewheel mechanisms so that the motor does not affect coasting or zero-assistance pedaling.
As an off-shoot of the low-end market, there's a DIY enthusiast market. This market has historically favored direct drive hub motors, as the extra thermal mass means they can survive being run above their rated power for a significant amount of time, and has historically favored systems that can easily be mixed and matched, so that they can customize controllers to increase power levels. Turnkey systems often get disparaged as "proprietary" unless they can easily replace the controller, or at least modify the stock controller. However, the turnkey Bafang BBS series of mid-drives, and the Tongsheng TSDZ2 mid-drive, have both seen adoption by the enthusiast community due to ease of modification, and the ability to run them through gearing to widen the useful operating range of the motor.
Both of these markets have tended to prioritize "simple" controllers. This selects against designs that use advanced motor technology that's harder to control (such as IPM designs with significant reluctance torque), and it selects against techniques like field weakening (although the enthusiast community is slowly coming around on this) reducing the efficient range of operation.
The high-end market has ended up focusing entirely on mid-drive systems, without significant advancement in motor technology as far as I can tell (although the Bosch drives might have a magnet configuration that enables significant reluctance torque? Not sure here), instead focusing on how the power delivery feels (which is a worthy development, and it's why I bought a Bosch-powered e-bike), as well as integration with systems like electronic shifting. These systems seem to be primarily oriented towards the European market and its legal limits, with only the speed limit adjusted for other markets, so the DIY enthusiast community tends to shun these for multiple reasons - the high-end drives all have form factors that require a custom frame designed around them making them useless for DIY retrofit, their power limits are rather weak compared to the more primitive DIY equipment, and their controllers tend to be extremely locked down (the newer ones even more so, due to European anti-tuning regulation).
(The Japanese low-end market nowadays is really just lower voltage, lower peak power versions of the high-end mid-drive stuff, made specifically for that market, due to unique e-bike laws that require torque-sensing pedal assistance (to be able to calculate rider input power, and output up to 2x that up to 10 km/h, ramping linearly down to 0x at 24 km/h), when everyone else's low-end stuff is just cadence-sensing.)
Tesla could improve this situation significantly. The Model 3/Raven rear motor and control software are vastly advanced beyond the 1990s tech being sold as state-of-the-art e-bike motors. (I did say fairly uniquely positioned earlier, as my understanding is that the motors used in Toyota's current-generation hybrid systems are at least close to Tesla in technology level (including the use of Halbach arrays), and possibly more cost-optimized (they get their Halbach array through what I suspect is a much simpler method of manufacturing, and the square windings may be cheaper to manufacture). Yamaha, who's already deep in the e-bike market, has access to that tech... but as far as I can tell, isn't using it.) With the majority of torque coming from reluctance, you greatly reduce cogging torque, meaning that freewheeling isn't needed, making regenerative braking practical. With field weakening (especially effective on motors with significant reluctance torque), you greatly increase the useful and efficient speed range of the motor, removing the need to run it through the bicycle's gearing. (However, there are vehicle dynamics reasons to use a mid-drive - reduced rotating mass, and for mountain bikes reduced unsprung mass. But, I suspect a hub motor would see significantly more adoption in hardtail applications if the severe power delivery drawbacks of current hub motors were removed.)
(Of course, I'm not actually sure that Tesla would build a bike that I'd want. I suspect Tesla would go for something like an "endurance" road bike geometry (a bit more slack than full-on bent over the bars aero positions, but still pretty aggressive), and then make things as minimal as possible as far as equipment, whereas... give me a super-slack city bike geometry, go full Dutch, give me fenders, give me a rack, give me a chaincase, etc., etc.)
So, there's quite a few players in the e-bike space currently, and it's even to the point where in the Netherlands, e-bikes now outsell all other types of adult bicycle combined. Tesla tends to shy away from markets that are already electrifying successfully.
However, I see room for massive improvement in the motor and control systems on e-bikes, that Tesla is fairly uniquely positioned to do.
There's approximately three markets that I see in the e-bike market.
The first market is the low-end market. In most of the world (Japan is a huge exception, I'll cover them separately), this is dominated by Chinese manufacturers, typically using off-the-shelf hub motors paired with off-the-shelf controllers and batteries. Direct-drive hub motors have fallen out of favor due to the high weight and poor efficiency (low RPM isn't good for efficiency), with geared hub motors taking over. All of these motors are either surface permanent magnet, or a very primitive form of interior permanent magnet with insignificant potential for reluctance torque, combined with relatively thick laminations to reduce cost, meaning that there's significant cogging/iron losses at reduced power levels. As this gets worse as you increase RPM, geared hub motors almost always have freewheel mechanisms so that the motor does not affect coasting or zero-assistance pedaling.
As an off-shoot of the low-end market, there's a DIY enthusiast market. This market has historically favored direct drive hub motors, as the extra thermal mass means they can survive being run above their rated power for a significant amount of time, and has historically favored systems that can easily be mixed and matched, so that they can customize controllers to increase power levels. Turnkey systems often get disparaged as "proprietary" unless they can easily replace the controller, or at least modify the stock controller. However, the turnkey Bafang BBS series of mid-drives, and the Tongsheng TSDZ2 mid-drive, have both seen adoption by the enthusiast community due to ease of modification, and the ability to run them through gearing to widen the useful operating range of the motor.
Both of these markets have tended to prioritize "simple" controllers. This selects against designs that use advanced motor technology that's harder to control (such as IPM designs with significant reluctance torque), and it selects against techniques like field weakening (although the enthusiast community is slowly coming around on this) reducing the efficient range of operation.
The high-end market has ended up focusing entirely on mid-drive systems, without significant advancement in motor technology as far as I can tell (although the Bosch drives might have a magnet configuration that enables significant reluctance torque? Not sure here), instead focusing on how the power delivery feels (which is a worthy development, and it's why I bought a Bosch-powered e-bike), as well as integration with systems like electronic shifting. These systems seem to be primarily oriented towards the European market and its legal limits, with only the speed limit adjusted for other markets, so the DIY enthusiast community tends to shun these for multiple reasons - the high-end drives all have form factors that require a custom frame designed around them making them useless for DIY retrofit, their power limits are rather weak compared to the more primitive DIY equipment, and their controllers tend to be extremely locked down (the newer ones even more so, due to European anti-tuning regulation).
(The Japanese low-end market nowadays is really just lower voltage, lower peak power versions of the high-end mid-drive stuff, made specifically for that market, due to unique e-bike laws that require torque-sensing pedal assistance (to be able to calculate rider input power, and output up to 2x that up to 10 km/h, ramping linearly down to 0x at 24 km/h), when everyone else's low-end stuff is just cadence-sensing.)
Tesla could improve this situation significantly. The Model 3/Raven rear motor and control software are vastly advanced beyond the 1990s tech being sold as state-of-the-art e-bike motors. (I did say fairly uniquely positioned earlier, as my understanding is that the motors used in Toyota's current-generation hybrid systems are at least close to Tesla in technology level (including the use of Halbach arrays), and possibly more cost-optimized (they get their Halbach array through what I suspect is a much simpler method of manufacturing, and the square windings may be cheaper to manufacture). Yamaha, who's already deep in the e-bike market, has access to that tech... but as far as I can tell, isn't using it.) With the majority of torque coming from reluctance, you greatly reduce cogging torque, meaning that freewheeling isn't needed, making regenerative braking practical. With field weakening (especially effective on motors with significant reluctance torque), you greatly increase the useful and efficient speed range of the motor, removing the need to run it through the bicycle's gearing. (However, there are vehicle dynamics reasons to use a mid-drive - reduced rotating mass, and for mountain bikes reduced unsprung mass. But, I suspect a hub motor would see significantly more adoption in hardtail applications if the severe power delivery drawbacks of current hub motors were removed.)
(Of course, I'm not actually sure that Tesla would build a bike that I'd want. I suspect Tesla would go for something like an "endurance" road bike geometry (a bit more slack than full-on bent over the bars aero positions, but still pretty aggressive), and then make things as minimal as possible as far as equipment, whereas... give me a super-slack city bike geometry, go full Dutch, give me fenders, give me a rack, give me a chaincase, etc., etc.)
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mspohr
Well-Known Member
Thanks for this analysis. I agree. Most ebikes are primitive. Lack of regen is a glaring omission.
Someone could do much better.
Watts_Up
Well-Known Member
This project is a little bit like finding a solution for a problem that doesn't exist, or just to say KISS (Keep It Simple Stupid).
However, I found some very interesting new ideas, such as 'Auto Pilot' for steering the front wheel.
Note: I used bicycle all my life for transportation, but I found some issues that are not easy to solve.
- First is the weather dependency, as rainning, strong wind, or cold weather are limitations for daily usage.
- Distance and duration to use, hills and abscence of specific bicycle lanes are some other issues.
- Storage during the day, or easy folding into a car trunk, or transporting the bike when using a bus, train, or metro.
Jim R
Member
My reluctance to ride a bike is based on my belief that North American drivers don't have enough respect for the bike rider. In other words, I don't feel safe riding in the city/country, sharing the road with cars. We are married to our cars and even shy away from buses and trains if we can drive to work in our car without great expense of parking.
Our daughter has an exchange (Emma) student from Norway this year. During our initial meeting this summer she commented on how we drive everywhere. Got us thinking "why" when we drove our car to another store across the huge 
mall parking. Not enough to get actually get out of the car and walk but we laughed when I reminded her of Emma's comment. Wife's sciatica is really the reason we didn't just walk. But you're right we drive when we could walk all the time.
Couple of other interesting tidbits from our conversation. It's cold in Norway and when I asked how they cope she said it's not too cold, just bad gear! I really thought this was a great attitude.
Oh yea little boys in Norway are afraid of catching cooties from girls just like us. Who'd have thought that? They also say you can get girl lice.
mall parking. Not enough to get actually get out of the car and walk but we laughed when I reminded her of Emma's comment. Wife's sciatica is really the reason we didn't just walk. But you're right we drive when we could walk all the time. Couple of other interesting tidbits from our conversation. It's cold in Norway and when I asked how they cope she said it's not too cold, just bad gear! I really thought this was a great attitude.
Oh yea little boys in Norway are afraid of catching cooties from girls just like us. Who'd have thought that? They also say you can get girl lice.
Thumper
Active Member
I have been riding an electric bike for 10 years. I'm lucky because the town I live in is very bike friendly with lots of bike lanes and paths and was the first to receive the League of American Bicyclist golden award. I find that having the Ebike gets me to use it more for errands than I would if it was just pedal. You get things done faster and thus it is more practical. This effect is magnified if you are getting groceries or other loads. I installed a kit from this company Home before they carried Benfang but they are well engineered and not difficult for a do-it-yourselfer. The website could be better designed so keep poking around until you find what you want.
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