Power needed to eliminate need for gears....

[AHicks]

I like the speed thing but since I am too old I would not want to ride that fast. I am afraid with the increased speed that Ebikes will be banned from some of the great trails.

The bigger point here is NOT how fast the big DD motors (1000w+) will allow us to go. They're going to use a tremendous amount of battery power to do that other than in short bursts, making those kind of speeds impractical. The bigger point, to my way of thinking anyway, is their ability to provide large(r) amounts of starting torque - approaching that of popularly used gear drives - without requiring/using huge amounts of power, and without the down sides related to gears. They can also be limited as far as how fast they can go. That's what's going to make them popular.

 

[fitzmotor]

I believe this is a power and speed capability that is compelling for ebikes to be truly "transportation" capable while being compellingly simple.

I just wondering how many ebikers would prefer an urban mobility ebike with that capability.

The simplicity of single speed really shines in off road super rough terrain, it is somewhat limiting on the road though if you want high mph, I just gear it so it's okay on the road but great off road, the power requirements of a single speed is greater than a geared bike, after riding both for long periods of time, I enjoy the single speed the most.

Here in Ca, to be a class 2 bike (750w/20mph) I can go anywhere, even past the "no motorized bicycles" signs as it's classified as a electric bicycle, I ride around on the streets in low power, its easier to be legal than risk getting hassled, off road, I turn it up and have fun.

First post here, I guess I will jump in with my 2 cents, only worth a penny.

 

[Jelester]

The simplicity of single speed really shines in off road super rough terrain, it is somewhat limiting on the road though if you want high mph, I just gear it so it's okay on the road but great off road, the power requirements of a single speed is greater than a geared bike, after riding both for long periods of time, I enjoy the single speed the most.

Here in Ca, to be a class 2 bike (750w/20mph) I can go anywhere, even past the "no motorized bicycles" signs as it's classified as a electric bicycle, I ride around on the streets in low power, its easier to be legal than risk getting hassled, off road, I turn it up and have fun.

First post here, I guess I will jump in with my 2 cents, only worth a penny.

I like the gearing as this gives me a challenge plus the gearing makes my battery last many times longer.

 

[indianajo]

[QUOTE="Deleted Member 4210,

In otherwords, since a rider is barely providing maybe an 1/8th of the total power, whats the point of even having something with pedals on it, when you have 2000 watts ?

Your leg power is barely even part of the equation.

[/QUOTE]
I have a 1000 watts kit with throttle and even with 3 cars in front of me I can make a 6 second traffic light it accelerates so fast. Traffic lights don't extend for bikes because they don't sense them. The walk buttons are 20' off the lane.
But I pedal everywhere else unless the wind is >10 mph in my face or I'm going further than 25 miles. I use 3 sprockets every stop to speed pedaled acceration. With favorable wind, a fourth speed. The battery is a wind equalizer, or extends my range from 25 miles/day to 50 miles- at 12 mph, not 28.

 

[WilliamT]

I believe this is a power and speed capability that is compelling for ebikes to be truly "transportation" capable while being compellingly simple.

I just wondering how many ebikers would prefer an urban mobility ebike with that capability.

Thanks, but no thanks.

I commute everyday by ebike and use around 180-210 watts of assist carrying a full load on a Radwagon cargo bike. I average about 13-15 mph with the assist at Level 2 and a low enough gearing that I can maintain a good cadence. I just want something that helps make pedaling a little easier.

 

[harryS]

Ken, you proposed a 2000W DD motor with a single 52/16 gear, which is 3.25. Never ridden one, but surmise that a 2000W DD with enough battery can be ridden w/o pedals. I know some riders have done that...remove the chain.

A 3.25 ratio is similar to the 46/14 on my mountain bikes. I'm flabby and cannot come close to the 107 beats/min cadence necessary to sustain 28 mph on a 700cc bike with 46/14. Also, that's a pretty high gear ratio to ride home on a motor that size w/o power.

I like smaller motors and using the gears to help them out with pedaling. That's where ebikes fit into my life at the moment. Perhaps some day in the future I'll not be pedaling. Who knows.

 

[MarkF]

Not every bike is going to be for everybody. Plenty are happy with the way most are. I personally like the idea of more power. Just because a bike has 2000 watts doesn't mean you have to drive it with no pedalling and in a way that is distributive. There are motorcycles that are capable of insane speeds but you don't see them all over the news abusing the power they have. Some of you seem to think just because a bike is powerful, people will not know how to ride them in a proper way. Which is ridiculous. I like your thinking Ken and want a bike capable of going the speeds I want to ride and has the power I want. I also have a class 1 bike and enjoy it almost everyday. But as a commuter it's too slow to drive down the main busy roads like to the gym. I'm also a big fan of the stealthy looking bikes that don't even look like an ebike. So I don't think it's fair to deny people the bike they want just because it's not your cup of tea. And that's my 2C

 

[Feliz]

Aren't we regulated enough, we're talking about bikes for gosh sakes. I like the point Mark made about motorcycles, I restored, rode, and raced motorcycles most of my life, I just quite riding when I turned 80. I never had one speeding ticket, had an accident, or caused anyone personal injury, or even dropped a bike. I think I can handle my 1000W Bafang BBSHD powered 60 pound bike which won't even exceed 30 mph. And it's not just about power, I have four other bikes, one class one and three class two all three limited to 20 mph.

 

[Ken M]

I like the speed thing but since I am too old I would not want to ride that fast. I am afraid with the increased speed that Ebikes will be banned from some of the great trails.

I'm definitely not suggesting the faster capability for trail / mtn bikes where the electric assist is primarily about helping on climbing. My thoughts are entirely about transportation merit where sometimes you are on the road side bike lane that is certainly safe for speeds up to 35mph (as many road bike riders will exceed on even just slight downhills). The merits of being able to maintain a higher average speed (say 25-30mph) for commuting are obvious and I'm not suggesting this is some kind of hot rod speed that will endanger anyone (bike riders tend to ride at the speed comfortable for them and the situation because you are not protected).

Based on my riding experience when you are riding at speeds above 25mph the rider input becomes a small % of the total power needed so gearing may not be essential on an ebike capable of speeds higher than that. Mainly about simplifying the drive train - ie a fixie with a 2000W peak drive system would make for a very nice transportation capable ebike (just because the power is available doesn't mean it's used all the time so it's still a bike in my opinion while many want to call it an emoped / emotorcycle - probably because they work for DMV or insurance companies).

 

[Ken M]

The simplicity of single speed really shines in off road super rough terrain, it is somewhat limiting on the road though if you want high mph, I just gear it so it's okay on the road but great off road, the power requirements of a single speed is greater than a geared bike, after riding both for long periods of time, I enjoy the single speed the most.

Here in Ca, to be a class 2 bike (750w/20mph) I can go anywhere, even past the "no motorized bicycles" signs as it's classified as a electric bicycle, I ride around on the streets in low power, its easier to be legal than risk getting hassled, off road, I turn it up and have fun.

First post here, I guess I will jump in with my 2 cents, only worth a penny.

Hi Fitzmotor, Good feedback. There is ample data available that illustrates how much power is needed to sustain speeds over 20mph on a bike that illustrates the point that the human element becomes an insignificant % of the power needed to go faster so the idea of a single speed ebike begins to make sense if the drive system is say 54V/40A or upwards of 2000W. I still believe strongly in the value of human input in getting the bike started and being engaged up to 20mph (just the exercise component alone is needed for our obese society) but for effective transportation an ebike may need to achieve speeds up to say 35mph (this is a speed reached by most road bikes going downhill so please people refrain from fear mongering that is a speed that only mopeds and motorcycles should do such that registration and insurance is justified).

Anyone that had ridden some of the class 3 ebikes (with assist to 28mph) quickly realizes that they are pretty much under-powered because you typically have to pedal very hard to achieve that speed and you are unlikely to sustain it for long. Why is it that regulations seem to want to prevent ebikes from being able to sustain an average speed of 28mph without wearing out the rider?

 

[Ken M]

Aren't we regulated enough, we're talking about bikes for gosh sakes. I like the point Mark made about motorcycles, I restored, rode, and raced motorcycles most of my life, I just quite riding when I turned 80. I never had one speeding ticket, had an accident, or caused anyone personal injury, or even dropped a bike. I think I can handle my 1000W Bafang BBSHD powered 60 pound bike which won't even exceed 30 mph. And it's not just about power, I have four other bikes, one class one and three class two all three limited to 20 mph.

What is amazing is that some of the posts on this string seem to think that at 80 you must be a crazy person to ride your ebike as fast as 30mph. They think you must be plowing over pedestrians and tearing up infrastructure to be going that fast when I just think you are going at a speed that makes the ebike a very effective human scale transportation solution. I guess the opinions vary widely when you start talking about riding a bike faster than 20mph...which I think was doing when I was like 12 years old.

 

[Ken M]

Ken, you proposed a 2000W DD motor with a single 52/16 gear, which is 3.25. Never ridden one, but surmise that a 2000W DD with enough battery can be ridden w/o pedals. I know some riders have done that...remove the chain.

A 3.25 ratio is similar to the 46/14 on my mountain bikes. I'm flabby and cannot come close to the 107 beats/min cadence necessary to sustain 28 mph on a 700cc bike with 46/14. Also, that's a pretty high gear ratio to ride home on a motor that size w/o power.

I like smaller motors and using the gears to help them out with pedaling. That's where ebikes fit into my life at the moment. Perhaps some day in the future I'll not be pedaling. Who knows.

Regardless of cadence the human input into the power required to sustain higher speeds (say over 25mph) becomes a small %. I was suggesting a gear ratio that would allow reasonable power input for speeds from say 10-25mph and then just allow the motor to kind of take over under throttle because even if you can gear the bike to keep the cadence reasonable you will not be aiding the motor much anyway. Why waste gearing when it achieves nothing.

If you have ever ridden a fixie you understand that it's not so hard to occasionally get the bike started from a stop - we can all put in a short burst of high torque / power to get the bike going 15mph in about 15 seconds. That is where we as humans are effective on a bike (sure gearing helps but when you have a good electrical drive system allow it to take over where we are not effective).

I'm just kind of on this idea that ebikes need to go faster than 20mph (or even 28mph) to reach their true potential to be fantastic human scale transportation. None of us can ignore that time is money and that commute times will be much less if the ebike can sustain say average 30mph vs 15mph that is probably possible on a current class 1 ebike. Human power is very effective at getting a bike to say 15mph so the potential for exercise and effective human input is still there on a single gear ebike but allow the drive system to dominate at the higher speeds where the motors are much more efficient and required to sustain the higher speeds. This is a product that makes sense....

Far too many people keep bring up the fear of a bike going 30mph when I know that I can ride my traditional road bike to speeds of around 40mph for some distance on a slight downhill. I just don't see any merit in the argument that going faster than 20mph on an ebike is far too dangerous when people riding traditional bikes are doing it - that argument is meritless.

 

[Ken M]

I hope all that makes sense. I understand that a 2000W DD hub motor would have adequate power to not require rider input, but my thought is that most riders will understand that the range and health benefits are far greater when they are fully engaged in pedaling from start to say 25mph.

If I had the fixie ebikes described I would not use the throttle at all below say 10mph. I know that DD hub motors are inefficient at slow speeds. I would use the throttle as needed when riding above 10mph but I'd continue to pedal to sustain some effect cadio level for the health benefits (our obese society should consider the same). Obviously above say 20mph the motor become much more efficient and needed to sustain those speeds and at higher speeds when the cadence is just not realistic for human input I'd just run under throttle and maybe focus on getting a bit more aerodynamic to reduce the load on the drive system.

I will again bring up that anyone that really understands gearing will understand that the current mid-drive systems become less efficient and effective at higher speeds because they have mechanical efficiency issues going thru the chain ring gearing. This is just a fact that many people don't understand and the mid-drive ebike companies are not going to tell you in their marketing. Mid drives are best for starting and climbing as slow to moderate speeds but not good at sustaining high speeds. In Europe where their legislation has locked down low power drive systems (like 250-350W) they are really the only drive systems technically fit to be a solution. The US federal limit of 750W (a static rating that is nebulous) does not lock us into mid-drives or even sub-750W direct drive hub motors as any motor can be statically rated at 750W.

We need effective human scale transportation to help rid the gridlock in cities. We need people that think ebikes going faster than 20mph should be regulated as mopeds or motorcycles to be kind of sidelined.

 

[Nutella]

Holler when you see electric versions of those on the market. I think something like that would be pretty interesting, as long as there was a reasonable range available!

https://electrek.co/2018/08/27/electric-vespa-the-elletrica-production/

 

[harryS]

Regardless of cadence the human input into the power required to sustain higher speeds (say over 25mph) becomes a small %. I was suggesting a gear ratio that would allow reasonable power input for speeds from say 10-25mph and then just allow the motor to kind of take over under throttle because even if you can gear the bike to keep the cadence reasonable you will not be aiding the motor much anyway. Why waste gearing when it achieves nothing.
.

In that case, why not go something like 44/16, as you won't be pedaling most of the time? Then when you do do that, you have something more manageable rather than the stiffest gear combo on your typical mountain bike, The original Sondors fatbike was a single speed with similar gearing.

You want to have gearing that supports high speed, but most riders don't have the muscle to add anything to a powerful hub motor going as fast as it can. With smaller motors, I agree with your premise. Say a smaller hub motor tops out around 24 mph, and it's quite reasonable to have a road gear like 55/14 to add leg power.

There are a few small motors (Xiongda) that have two selectable gears. In this case, they set the motor for moderate speeds on flat ground, with the option of picking the second internal gear for slow/steady hill climbing. I hear they break too quicky though. Maybe in 5 years, we'll have some quite capable 3-4 speed hub motors. Maybe not, unless it comes from Tesla figuring out how to make their cars do that,

Meanwhile I find shifting fun, and love when the chain moves smoothly gear to gear, front and rear. I would imagine a commuter spends more time watching traffic and the clock than enjoying how the bike responds. Different needs. I respect that. You have to be somewhere on time. You don't need the workout.

 

[Ken M]

In that case, why not go something like 44/16, as you won't be pedaling most of the time? Then when you do do that, you have something more manageable rather than the stiffest gear combo on your typical mountain bike, The original Sondors fatbike was a single speed with similar gearing.

You want to have gearing that supports high speed, but most riders don't have the muscle to add anything to a powerful hub motor going as fast as it can. With smaller motors, I agree with your premise. Say a smaller hub motor tops out around 24 mph, and it's quite reasonable to have a road gear like 55/14 to add leg power.

There are a few small motors (Xiongda) that have two selectable gears. In this case, they set the motor for moderate speeds on flat ground, with the option of picking the second internal gear for slow/steady hill climbing. I hear they break too quicky though. Maybe in 5 years, we'll have some quite capable 3-4 speed hub motors. Maybe not, unless it comes from Tesla figuring out how to make their cars do that,

Meanwhile I find shifting fun, and love when the chain moves smoothly gear to gear, front and rear. I would imagine a commuter spends more time watching traffic and the clock than enjoying how the bike responds. Different needs. I respect that. You have to be somewhere on time. You don't need the workout.

Good suggestions / ideas. A 44F / 16R will have a cadence around 100 at 22mph which isn't that bad. I was thinking that human added power is adequate to a bit higher speed, which is why I was thinking that 52F / 16R was a better combo if you had say a 52V / 40A drive system. In reality, the ideal fixie ratio for every rider could be easily established by changing the front and/or rear chain ring (I was always thinking that having a 2nd smaller chain ring with a rear tensioner would be nice to manually move down to if you ever lost battery power - always thought that fixies were always better with chain tensioners that super tight chains that wear out faster). I think that most riders could still manage most of the power to get the bike up to say 15mph without too much help from the motor, but a 44/16 would certainly be better.

I too like shifting as I tend to be very engaged in riding my ebike but I have also just left it in 8th gear (which is 44F / 11R) and I have no problem riding it as a pedelec that way (it's a 750 DD hub motor pedelec without a throttle) so I just started thinking that the gearing on a commuting ebike isn't that essential especially at higher assist levels (optimizing the human input adds very little to the effectiveness of the ebike). I like the idea of still getting as much exercise as wanted, but when commuting most riders are going over 15mph and a 52/16 fixie ratio is pretty optimized for. On hills you would just throttle to sustain speed instead of using gearing (again optimizing the human input is not that important on a powerful ebike).

 

[Alaskan]

It seems that various posts in this thread are talking past one another.

To me the key issues are a matter of definitions for public safety, access, legal and insurance purposes.

At what point does a powered, two wheel vehicle cease being a bicycle and become a moped or an electric motorcycle?

This is not just a semantic exercise. Questions about minimum operator age, insurance requirements, registration, access to mixed use trails and responsibilities on the road hinge on making clearly identifiable specifications and differentiations between these terms.

We should be able to ride what ever combination of technology that can be safely designed and built. We should also be prepared that, if we push the envelope far enough, we just might end up outside the envelope.

 

[Ken M]

It seems that various posts in this thread are talking past one another.

To me the key issues are a matter of definitions for public safety, access, legal and insurance purposes.

At what point does a powered, two wheel vehicle cease being a bicycle and become a moped or an electric motorcycle?

This is not just a semantic exercise. Questions about minimum operator age, insurance requirements, registration, access to mixed use trails and responsibilities on the road hinge on making clearly identifiable specifications and differentiations between these terms.

We should be able to ride what ever combination of technology that can be safely designed and built. We should also be prepared that, if we push the envelope far enough, we just might end up outside the envelope.

Agreed, but how does an ebike assist limit of 20mph make sense (the current limit for ebikes that will not require registration, insurance, or minimum age being adopted by most states) when virtually everyone that rides bikes can easily exceed that speed at least for short distances on a traditional bike (if you consider that some recumbent riders are sustaining around 30mph on flats when they have good aerodynamics that limit really become ?????).

Note: Recently the speed record for a human powered bike was set at something like 180mph and I don't see anyone arguing it was not done on a bike....no one has said that it was a moped or motorcycle so insane speeds are possible on a human powered bike under certain conditions.

As for public safety, I don't believe there have been any studies that provide data as to what is a safe speed for an ebike vs a non-ebike. I'm not advocating crazy fast assist speeds. I'm merely suggesting that if I can ride at 35mph on my road bike down a moderate grade for a fairly significant distance then what is the justification for setting assist speeds for an ebike at 20mph (other than maybe protecting oil and gas companies and/or putting money into DMV and insurance companies).

I like what should be the federal interpretation of a bike - if the rider is engaged in providing some input then it's remains classified as a bike. States are not supposed to change this definition but they can establish regulations as to where bikes and ebikes can be ridden. That is my understanding. I think people talk past each other on this subject because it's not as simple as saying no bike should ever go faster than 20mph because that is the safe limit. It's not that simple, but some feel it is.

I would prefer that the speed limit for an ebike be established just like it is for automobiles. Some roads / bike paths should maybe have a 25mph speed limit, some are safe to 35mph, etc. Just because a sports car can achieve 250mph doesn't mean the owner of that car can drive at that speed if they wish.

If at 57 I can pedal my road bike without assist to say 35mph for say 1/4 mile, than it just seems reasonable that maybe an ebike should remain classified as a bike even if the assist can achieve that speed. I've seen people respond saying a short distance burst of speed is entirely different than a sustained speed, yet they never present anything logical to support that position. Should we classify an aerodynamic recumbant that someone decently capable of riding at a sustained speed of 30mph as illegal or say that a 15 year old kid can not ride it? I don't have all those answers but I do think we need human scale transportation more than we need 20mph assist speed limits. That much I do know!!!

 

[Ken M]

It seems that various posts in this thread are talking past one another.

To me the key issues are a matter of definitions for public safety, access, legal and insurance purposes.

At what point does a powered, two wheel vehicle cease being a bicycle and become a moped or an electric motorcycle?

This is not just a semantic exercise. Questions about minimum operator age, insurance requirements, registration, access to mixed use trails and responsibilities on the road hinge on making clearly identifiable specifications and differentiations between these terms.

We should be able to ride what ever combination of technology that can be safely designed and built. We should also be prepared that, if we push the envelope far enough, we just might end up outside the envelope.

I do want to add that if public safety was the only concern in this debate we would not have 70-75mph speed limits on interstates (if human life were truly considered of infinite value we'd all be driving around at 10mph). There some correlation that this does increase risks but we balance those risks with economic considerations. It's not evil...We just do.

I've seen the argument that maybe a 15 year old kid should not be allowed to ride a class 3 ebike. Maybe there is some justification to that but when I was 15 I was riding a 50+hp 250cc motocross motorcycle for fun occasionally so I'm not sure if someone not old enough to get a drivers license should not be allowed on a class 3 ebike. At 15 years of age just riding any bike on the streets is adding a hell of a lot of safety risks.....a faster ebike is negligible in that equation in my opinion (maybe they would be safer being able to more effectively keep up with the flow of traffic).

 

[Bruce Arnold]

Anyone that had ridden some of the class 3 ebikes (with assist to 28mph) quickly realizes that they are pretty much under-powered because you typically have to pedal very hard to achieve that speed and you are unlikely to sustain it for long.

That statement sounds so absolute and certain, and yet it requires modification.

I can sustain 28 mph on my CrossCurrent S for as long as the battery holds out, and I'm old, fat, and have COPD.

It happens that I live in an area that has few hills, so that does make a difference. I wouldn't say "anyone" could do it, because I myself can't when I go to a locale such as my daughter's home which has lots of big hills.

And that's the problem with saying "anyone."