Does this make sense? (no chain or belt, pedal operated generator and wires to the rear hub motor)

[classicalgas]

Not a fly by night scheme, from what I can tell...https://electrek.co/2021/08/31/radical-new-electric-bike-drive-systems-requires-no-chains-or-belts-entirely-ride-by-wire/

The company is claiming only 5% less drive efficiency than a chain. I wonder if that's a brand new, clean and properly lubed chain (ideal world) or a well used and dirty one (real world)

Seems to me that installed in a tadpole trike (long chain) you might not have much weight penalty, and you could maintain a steady cadence regardless off terrain (or stopped ) both would help with the drive efficiency penalty. Thoughts?

 

[MadRhino]

So you will pedal your ebike, and with the same effort, you will go 5% slower than a plain pedal bike. What an invention!!!

I want a crank that drives a coolant pump. I will take care of the power fed to the motor, enough to make pedal input negligible. Then, I will pedal to keep it cool. :wink:

 

[ccihon]

If all this accomplished was eliminating chain drive complexity etc, one could drive a hydraulic motor with the cranks and run fluid line in a closed system to a hydro motor at the rear - line running to the back and return to the front....negligible loss and easy placement etc. I think the promise this electric system adds is how simply it integrates to power storage via battery and addition of battery power for assist.

Not sure how gear ratios etc can be changed here, if at all.

 

[Chalo]

Thoughts?

It's horseshit, of course. They are not the first to conceive it, and they won't be the last. But if there were any merit in it, it would have been in commercial products for a century or more already.

It would be interesting to see a proof of concept-- not to find out whether it's good, but to see what degree of bad we're talking about. Might be fun in a perverse way, like an Alenax, rowing bike, Kangaroo dwarf safety bike, or any number of other offbeat bicycles that also suck.

 

[ZeroEm]

Have had thoughts more in the line of a peddle car where the peddles are more to make it legal not really used to propel it. Maybe enough charge for the lights. Would call it peddle by wire.

 

[TrotterBob]

Its been done a few times and it makes perfect sense. But without a flywheel I'm wondering if pedaling would feel natural. Would you feel a similar amount of resistance as you would pulling a chain?

https://www.youtube.com/watch?v=7hfClQh3rxM

 

[classicalgas]

Well, obviously there's a battery involved, and (it looks like) regen braking and a sophisticated "smart" system to handle the balance and distribution of energy, and it's a low power( 250 w?) setup.

If the generator is geared up fairly high (I'd think it would have to be) you'd have some flywheel effect, and a much smoother load at the pedals than a conventional drive.

Drastic reduction in maintenance and moving parts is being pushed as an advantage.

 

[ZeroEm]

by TrotterBob » Sep 03 2021 10:28pm

Its been done a few times and it makes perfect sense. But without a flywheel I'm wondering if pedaling would feel natural. Would you feel a similar amount of resistance as you would pulling a chain?

I like the solid feel of a chain, so the resistance of a generator would be unnatural, maybe like a peloton. But ghost peddling is worst.

by classicalgas » Sep 03 2021 11:48pm

Well, obviously there's a battery involved, and (it looks like) regen braking and a sophisticated "smart" system to handle the balance and distribution of energy, and it's a low power( 250 w?) setup.

If the generator is geared up fairly high (I'd think it would have to be) you'd have some flywheel effect, and a much smoother load at the pedals than a conventional drive.

Drastic reduction in maintenance and moving parts is being pushed as an advantage.

I would not try to pass it as better. 250w is peddle assist with a chain. Want to pull a hill with 250w and no chain good luck.
I like to think about it but just does not seem worth playing with. simple chain with pas and a powerful motor would work better.

 

[sleepy_tired]

The only advantage of this sort of setup is if you want infinitely variable transmission. So you can have your ideal cadence regardless of actual bicycle speed. In a theoretical level this would make up for the drive-train losses by improving human efficiency.

On a practical level it is nonsense.

I think the likely true purpose of this device is to fulfill some nonsense regulatory requirement for pedal operated ebike without having to deal with the complexity of designing and maintaining a actual human mechanical drive train. This would be for things like package delivery "bikes" were the chain and gears would get in the way of the cargo area. At that point the pedals are just vestigial. It then becomes a 2 pedal gas pedal and the rider contributes nothing except a token amount of effort to moving the conveyance.

 

[LewTwo]

I think the likely true purpose of this device is to fulfill some nonsense regulatory requirement for pedal operated ebike ...

 

[dogman dan]

I like the advantage, of having a bike that could weigh well under 20 pounds, weigh 40 pounds or more.

5% my ass, only if you compare it to a lead sled beach cruiser.

And as for complexity and breakage, boy, I have had so much trouble with chains and derailleurs, I really wish they would come up with a system that has the bugs worked out of it. :lol:

But to to be honest, if the 16 year old at walmart assembles your bike, you do have a maintenance problem with the drive system, the brakes, and quite possibly the front forks are on backwards.

 

[raylo32]

This idea makes me ask "why". No real advantages. Tired of hearing about the "complexity" of chains and cogs. Seriously? Without a massive flywheel the pedaling feel would be shite. And you would lose the redundancy of the mech drivetrain should you have a motor or battery issue. Or even now with this a generator issue. Talk about complexity.

 

[MadRhino]

People like to find good sides to things that are obviously inefficient. Then they see the good sides and blind the most important. Transforming crank work into motion power can be done in many ways. Now we crank a generator, that has some efficiency loss like any other. The energy produced is regulated to charge a battery, that feeds a controller. Then this energy will make motion through a motor, then a wheel, then a tire. Every step between the human body calorie and the tire grip on the ground, has it own weight and energy loss. All those losses add, thus only a part of your work is transformed into motion. If you pedal the bike to move, it will be supplied much more of your energy with a simple bicycle drivetrain.

If crank work is not a factor, because the motor is fed so many times the human power that it is negligible, stop pushing behind 40 running horses and stop trying to charge a battery that would make you pedal a hundred miles to make your bike moving three and a half. Evolution is simplifying means and optimizing efficiency, not the opposite.

 

[E-HP]

I like having the motor assist when I ride. I guess they feel that there's a market of a negative 5% assist, maybe for exercise for folks that don't have hills or headwind to increase the amount of effort.

 

[TrotterBob]

I like having the motor assist when I ride. I guess they feel that there's a market of a negative 5% assist, maybe for exercise for folks that don't have hills or headwind to increase the amount of effort.

Or it will be a great success as everywhere you ride will essentially be flat ground and your pedal effort to achieve a certain wattage will not change. With the added bonus of regenerative braking.

Chain drives are 95% efficient or if you have very deep pockets and you've been watching GCN videos on youtube you can achieve up to 97%. But in the real world with dirty chains and off the shelf Sram/Shimano/Campy cassettes its probably more like 91% efficient.

 

[E-HP]

I like having the motor assist when I ride. I guess they feel that there's a market of a negative 5% assist, maybe for exercise for folks that don't have hills or headwind to increase the amount of effort.

Or it will be a great success as everywhere you ride will essentially be flat ground and your pedal effort to achieve a certain wattage will not change. With the added bonus of regenerative braking.

Chain drives are 95% efficient or if you have very deep pockets and you've been watching GCN videos on youtube you can achieve up to 97%. But in the real world with dirty chains and off the shelf Sram/Shimano/Campy cassettes its probably more like 91% efficient.

250W isn't going to be climbing any hills, since there is no pedal effort going to drive the wheels. It's a flat ground bike by default.

 

[SlowCo]

250W isn't going to be climbing any hills, since there is no pedal effort going to drive the wheels. It's a flat ground bike by default.

Nonsense!
You can climb hills with 250W only a lot slower than with 2500W...

 

[E-HP]

250W isn't going to be climbing any hills, since there is no pedal effort going to drive the wheels. It's a flat ground bike by default.

Nonsense!
You can climb hills with 250W only a lot slower than with 2500W...

throttle only? maybe with a mid-drive.

 

[Silvaticus]

I agree with many things written by different people in this thread. This is really nonsense, I know of several similar developments in the last 20 years. They have not achieved any meaningful sales.
Tell me, have any of you tried to pedal on such a drive? I tried. So, I will say again that this is nonsense. This is designed for unhurried pedaling by feeble old women. If you try to pedal a little more aggressively, or step on the pedals while climbing uphill, then the pedals just twist and you can lose your balance.

 

[MadRhino]

Yep, and the claimed 95% efficiency is a joke. Like any other system, efficiency is spec at its optimal level and gets lower with any parameter change. And, this power has to go through a charger, a battery, a controller and a motor. Let’s say each of those are 95% efficient, they still add and, at the very best, one fifth of the crank work is lost before hitting the ground. If your speed is in the inefficient RPM zone of the motor, then it could be as little as half of your work that is really transmitted to the wheel.

The battery powers the motor. You power the wheel. That is fine and pretty efficient. If you work to charge the battery, your energy enters a succession of transformations that will suck a considerable part of it before hitting the ground.

 

[TrotterBob]

Yep, and the claimed 95% efficiency is a joke. Like any other system, efficiency is spec at its optimal level and gets lower with any parameter change. And, this power has to go through a charger, a battery, a controller and a motor. Let’s say each of those are 95% efficient, they still add and, at the very best, one fifth of the crank work is lost before hitting the ground. If your speed is in the inefficient RPM zone of the motor, then it could be as little as half of your work that is really transmitted to the wheel.

The battery powers the motor. You power the wheel. That is fine and pretty efficient. If you work to charge the battery, your energy enters a succession of transformations that will suck a considerable part of it before hitting the ground.

Pedal energy would go from the generator thru a bridge rectifier and either into the batteries or into the speed controller. I dont see whats so inefficient about that.

 

[Silvaticus]

Yep, and the claimed 95% efficiency is a joke. Like any other system, efficiency is spec at its optimal level and gets lower with any parameter change. And, this power has to go through a charger, a battery, a controller and a motor.

Why do you think the idea of transferring the power you generate from a generator directly to the motor is not used in this electric bike? This is the most efficient way, but only in a previously known power range. If you try to work out more, the rotor will simply slip.
And yes, a perfectly lubricated chain drive has an efficiency close to 0.98, while a human's efficiency is only 0.28. Therefore, the maximum efficiency of the bicycle + person system is about 0.2744.

 

[MadRhino]

Yep, and the claimed 95% efficiency is a joke. Like any other system, efficiency is spec at its optimal level and gets lower with any parameter change. And, this power has to go through a charger, a battery, a controller and a motor.

Why do you think the idea of transferring the power you generate from a generator directly to the motor is not used in this electric bike? This is the most efficient way, but only in a previously known power range. If you try to work out more, the rotor will simply slip.
And yes, a perfectly lubricated chain drive has an efficiency close to 0.98, while a human's efficiency is only 0.28. Therefore, the maximum efficiency of the bicycle + person system is about 0.2744.

Eat proteins.
Yes the human body is inefficient in transforming food into work. It is the reason why we want the bike efficient.

Now let’s say the generator does feed the controller. WATT is the average controller efficiency? Then watt is the motor efficiency?

If the generator does feed the motor directly, it is a brushed motor. WATT is the average efficiency of brushed motor?

No matter how you do it, you are losing a lot of energy cranking to feed a system, as compared to cranking any bicycle drive train, even the cheapest 3 speed antique bike.

 

[docw009]

The folks who did the Mando Footloose must have made a killing selling all those bikes. They're everywhere!



https://www.cnet.com/roadshow/reviews/mando-footloose-im-review/

 

[MadRhino]

The folks who did the Mando Footloose must have made a killing selling all those bikes. They're everywhere!
footloose.jpg


https://www.cnet.com/roadshow/reviews/mando-footloose-im-review/

They are everywhere around you and nowhere else it would seem. I never saw one on the street. We should ask ES members, I bet the vast majority never saw one. And, the reviews are from neophytes who never had built an ebike.