Totally new concept for bike design - is it an ebike or not???

[ebikeerwidnes]

https://interestingengineering.com/...-a-new-e-bike-ditches-the-classic-bike-design

sooooo

bike by wire - could be set up with pedal assist - or possibly not - wonder if the losses and delays would ever make it NOT an ebike

interesting

 

[ColinJ]

It's an interesting idea but well maintained chain drive is pretty efficient - I doubt that the generator/motor combination would approach that efficiency.

I suspect that the bike would be heavier too.

If the efficiency were >= that of chain drive AND overall weight of the new e-bike were <= that of a conventional bike AND the if the cost were reasonable... show me the bike!!

 

[Twilkes]

I'm no physicist but surely pedalling a generator and then using the electricity from that generator to power a motor is going to be way less efficient than a chain drive. Even the article seems to be saying that being able to position the pedals anywhere is one of the key selling points of the system, not energy performance.

 

[classic33]

Wait while brake by wire starts appearing on everyday bikes. Not as an extra, bought later.

 

[a.twiddler]

Isn't this one of those old ideas that has kept resurfacing over the years, similar to the idea of a bike using some sort of flywheel to store energy gained going downhill to help get up hills. There are so many energy losses between what's generated and what gets to the motor that it would just be a means of slightly extending the range of a purely battery powered bike by charging the battery with the pedals. Another dubious variation on the perpetual motion theme. The article is pretty short on details. Pictures, road test reviews please!

 

[bonzobanana]

Seems more like drivetrain for a e-moped where the main power is the battery but you can recharge a bit from the regen on the motor going downhill and braking and also get some assistance from the person riding. That assistance could be more as there is variable resistance so you can get a higher level of power from the rider even on the flats and going at a slow speed compared to a normal bicycle because of the variable resistance.

On an ebike with a hub motor the motor drives one of the wheels directly through the hub and the rider provides power through the drivetrain to combine into an overall strong amount of power and the fact the motor system and rider power is kept completely separate actually massively reduces wear on the drivetrain but with this design the motor has to do all hill climbing for example so needs to be much more powerful and therefore heavier and that will need a more powerful battery and it will be combined into a larger stronger frame so much heavier than a standard ebike.

It sounds like a lot of expensive proprietary technology but as consumers we should be trying to keep ebikes environmentally friendly, easy to make, easy to repair, easy to keep a very long time. Expensive overly complicated designs should be avoided.

I think this technology could be used for small 4 person EV's with a pedal generator for each passenger so you could extend the range of that vehicle considerably but still be in comfort sitting down. Unfortunately the market at the moment is horrifically over-sized and heavy SUV EV's which are far more damaging and wearing to roads and couldn't realistically use such technology.

 

[IanSmithCSE]

Good morning,

I agree with the statements about it being an old idea (https://www.endless-sphere.com/forums/viewtopic.php?t=27704 thread from 2011!) and there are going to be significant losses and also I don't see how to make it an ebike under the current rules as it appears to need a throttle.

However, I also possibly like the idea, if they can come in at around 6-8kg for generator, motor, battery and gubbins.

I can see the market for a bike at around £1k-£2k weighing around or under 34lbs with something like a 150Watt Hour battery. The pedalling action/regen on downhills is then responsible for extending this small battery's range.

It's pretty much the same idea as the Fazua system, some extra power when needed, not a full on ebike that the rider doesn't really want to pedal at all.

If you set the pedalling to generate 75-100 watts then this is a comfortable load for most people, they won't get sweaty and assuming a 50% (35-50 watts) efficiency this would still be a very useful extension to the battery if it is being drained at around 125 watts per hour, very back of a fag packet 12 mph.

The battery would then be removed at the end of the ride(s) and topped up from the mains. As it is smallish it would be easier to mount onto the frame and easy to remove and charge at work without looking like you are taking the mick.

Better efficiency and a slightly larger battery would make for a very useful product, a longish distance commuter or a general purpose bike.

Don't forget the small weight and cost savings from having no chain, cassette, 2nd chainring and gear mechs.

Bye

Ian

 

[newfhouse]

Isn’t this just a variation on the idea of a pedal driven fan mounted behind the saddle producing a permanent tail wind?

 

[ericmark]

I read the "The drive system is composed of a small generator, a 250-watt wheel hub motor, a lithium battery, and a control unit on the handlebar." and think I have a 350 watt peak, 250 watt continuous rated hub, and I have pedal hard to get up hills.

There may be a version I am unaware of, but in the main it is considered the extra weight required to get regenerative braking will need more effort to get from A to B than it is worth.

However the big hurdle is the law, be it a scooter, skate board, or bike, once one adds a motor it is the legal bit which stops progress, this is why UK excelled over France in the early days of steam, the French government made it hard for the engineer to progress.

Before the law insisted it had to be propelled by pedals, with only electric assist, we had electric scooters in style of the old mods era which were legal on British cycle paths, even today the law is rather vague, 250 watt on a continuous basis, what is continuous? Clearly a 1000 watt motor is not legal on cycle paths, but 350 watt peak, is it or isn't it, I would say legal, but no one can say what a court would say.

So taking it to the silly stage, you sit on an exercise bike, which charges up the battery on your e-bike, then use the e-bike. There is no way to prove you used manual labour to charge the battery, so still limited to 250 watt.

I find I need to be doing 3 MPH or more to balance, under that it is walk assist. It does not matter what gearing you have, with a 22 stone body you can't get up a 1:6 hill with 250 watt.

 

[ColinJ]

I find I need to be doing 3 MPH or more to balance, under that it is walk assist. It does not matter what gearing you have, with a 22 stone body you can't get up a 1:6 hill with 250 watt.

Yes - 250 W would only get you to ~2 mph. You would need about 375 W to achieve ~3 mph.

 

[a.twiddler]

Minus 2, Minus 3? All those watts to go backwards? shome mishtake, shurely. Try reversing the terminals.

 

[ColinJ]

Minus 2, Minus 3? All those watts to go backwards? shome mishtake, shurely. Try reversing the terminals.

Put your specs on!

I was using '~' for 'approximately equal to'. Maybe I should have tried '~='?

There must be an easy way of typing the correct character. I'll be back...

Well, I can copy and paste it from elsewhere... ≈

Yes - 250 W would only get you to ≈2 mph. You would need about 375 W to achieve ≈3 mph.

Happy?

I'll find the proper way of doing it later. (No numeric keypad on my laptop, otherwise I would use that to type the keycode in.)

 

[Bollo]

The keys words in that article are “a press statement reveals”. It feels like a solution in search of a problem.

 

[ericmark]

I note my e-bike works fine if I can keep the speed over 4 MPH, this seems the cut off point, as soon as below 4 MPH output from motor drops off, wife's bike has mid motor so works through the gears, her peak output is 250 watt, my peak output is 350 watt but I can ride her bike up steeper hills than mine, as the motor works through the gears.

But the whole idea of the new bike is to remove the gears, and putting it simple 250 watt is not enough on its own. The G-tec uses a rubber belt drive so has also got rid of gears, but still has user input as well as the 250 watt, and being frank when using hub motor I tend to select top gear and never change gear except for really steep hills, so I can see how one ratio is enough for many roads.

However the weight limit of 16 stone kind of knocks out use of G-tec bike, the frame is weakened by having a removable section to replace the belt, I assume this is why low weight limit?