Cheaper bike

[D8ve]

I support crank on efficiency grounds.
In engineering terms using gears to maintain torque over a wide speed range is classic. It also allows a greater range of speeds while maintaining efficiency.
I like that.
Hubs have there own advantages of simplicity which is also nice too.
There is a place for both at the moment.

 

[Kudoscycles]

Trex,I suspect within this forum is someone who can provide the correct maths,my comment was taken off the Powerpedals website.
I have no motive on this one,the torque of the Tonaro at the back wheels is considerably higher than any TCM motor bike I have ridden. We all had opportunity to ride the Tonaro at the Eden project,it climbed a hill that no other bike tackled,many Pedelec members were there,the Tonaro used to be the benchmark that we all looked to,at that time.
With regard to torque....just thinking this logically if the torque on a bicycle is not higher at the back wheel than on the crank then what would be the point of having gearsets on bicycles.
As an aside I did find that if torque is force x radius,assuming a crank length of 175 mm and rider weight of 140 lbs - 80 ft lbs,or 109 Nm torque,Note this is rider weight and the force exerted on the pedals by the rider which can be 3 times his own body weight,resulting in a torque of maybe 400 Nm...which clearly explains why rider input has such a dramatic effect on hill climbing and chain load. Also the effective torque from an e-bike motor is much higher than the nominal figure,otherwise no electric bike would have any use for hill climbing....there the governments investment in my uni education and the wonderful student apprenticeship that Ford Motor Company paid for,was not totally wasted.
KudosDave

 

[trex]

...
What I mean is that it was not so much that the TCM was working well,it was that the SWX was working badly,note only at slow speed(less than 6mph). I ride my Secret bike ,it has an SWX motor, but the light weight and small wheels allow me to easily reach 6 mph so the problem can be overcome.
However,once we all realised the torque of the BPM motor was available at very low speeds (about 4 mph) and the power came in strongly at much lower motor speeds then the advantage of the crank drive was lost.
Also the hub drive system eliminated all the gear change problems associated with crank drive.
However,I must say that hill climbing is only one aspect of the rideability of these bikes and that the Bosch and Impulse drive systems have been developed to the point that they are very smooth bikes to ride,my favourite bike is still the KTM 400 sport with Bosch drive but it costs £2k.
I wonder how many manufacturers will be releasing BPM (or equivalent) motored bikes at the Eurobike show,early September....certainly the initial offerings from KTM are tending towards that direction.
KudosDave

classic spin, dave.
If extrapolated logically, BBS02 (BPM class power) should be allowed on legal e-bikes, would you say? the BBS02 is capable of 40mph when derestricted. Then you see my point: the power race is mad. The law will need to be clarified with regard to how much instant power e-bikes are allowed to have now before somebody gets seriously hurt.

 

[Deleted member 4366]

I support crank on efficiency grounds.
In engineering terms using gears to maintain torque over a wide speed range is classic. It also allows a greater range of speeds while maintaining efficiency.
I like that.
Hubs have there own advantages of simplicity which is also nice too.
There is a place for both at the moment.

That's what the theory says, but nobody has ever been able to prove it. My side-by-side trials show the hub motor to be more efficient. The KTM with hub motor trounced the Bosch in the hill-climbing efficiency test.

 

[trex]

The KTM with the P hub motor was powered with a 47V 10.5AH battery against 36V 8.4AH Bosch. For a fairer comparison, pitch BBS02 against Pana hub.

 

[Kudoscycles]

I support crank on efficiency grounds.
In engineering terms using gears to maintain torque over a wide speed range is classic. It also allows a greater range of speeds while maintaining efficiency.
I like that.
Hubs have there own advantages of simplicity which is also nice too.
There is a place for both at the moment.

D8ve....in theory yes...but at the moment we don't have a bicycle transmission system that was designed to be combined with an electric motor,the derailleur system with the necessity to lift the chain under load is not suitable.
Has the e-bike industry really moved on much since the guy who bolted an Audi windscreen wiper motor onto a bicycle?
Maybe we need to copy the motor car or motorcycle,which invariably attach the torque changing mechanism (the gearbox) seamlessly to the power source.
Trans-x of Taiwan bring to every Eurobike show a gearbox attached to a crank drive motor fitted into the bottom bracket,at the last show the gearbox was auto change. But this never seems to get beyond the prototype stage.
I could see someone like Bosch,who have the r&d and cash to go through the development ,but it should be a relatively simple design to attach a small gearbox to their existing motor....is this the future?
In the meantime their appear to be 3 choices..
1) BPM hub motor plus derailleur
2) TCM crank drive plus Nuvinci hub
3) Bosch type crank drive with power reduction on gear change
KudosDave

 

[trex]

dave, here is a suggestion: let dmsims have your Eiger for a few days, then he'll tell us how well the Eiger with the Nuvinci does on the 15%-20% hills around his house compared to derailleur.
Another suggestion: bring it to Redbridge next month.

 

[Kudoscycles]

classic spin, dave.
If extrapolated logically, BBS02 (BPM class power) should be allowed on legal e-bikes, would you say? the BBS02 is capable of 40mph when derestricted. Then you see my point: the power race is mad. The law will need to be clarified with regard to how much instant power e-bikes are allowed to have now before somebody gets seriously hurt.

I never find the power of any BPM motored legal bike to be excessive,if what is being sold by my London Dealer is typical it is taking the lion share of the mid range priced product.
Obviously any right thinking person would think that a 40 mph bicycle ridden by a 14 year old on a seafront or bridleway would be stupid.
I know I am going to regret asking this.....but what is BBS02?
What will bring this all to a head is the current sellers of mopeds and scooters,which are clearly the 500-800 watt bikes that I see millions of in China,they weigh 50-90 kilos and are very powerful.
The sellers claim all the usual no tax,mot,helmet,registration....but they also say that can be ridden by 14 year olds and you can refuse a blood test or breathalyser test....I read into that that their market is drunken 14 year olds who want to legally terrorise pedestrians. There is one advertising on this forum,is this a Pedelec ?
KudosDave

 

[flecc]

Trans-x of Taiwan bring to every Eurobike show a gearbox attached to a crank drive motor fitted into the bottom bracket,at the last show the gearbox was auto change. But this never seems to get beyond the prototype stage.
I could see someone like Bosch,who have the r&d and cash to go through the development ,but it should be a relatively simple design to attach a small gearbox to their existing motor....is this the future?

I doubt it could be the future since the concept has a fundamental flaw in the intrinsically hybrid e-bike field.

Electric motors for legal e-bikes only need two gears, or by a stretch three, to adequately cover the road speed range at near maximum efficiency.

Cyclists need many more to maintain optimums of cadence and personal efficiency, especially in challenging territory. So a combined gear system will always compromise one or the other.

The nearest we ever got to a solution to this conundrum was the Swizzbee, a motor driving one side of a form of wheel hub differential, the rider's derailleur driving the other side. The output into the wheel was the sum of the two inputs differentially adjusted.

 

[Kudoscycles]

dave, here is a suggestion: let dmsims have your Eiger for a few days, then he'll tell us how well the Eiger with the Nuvinci does on the 15%-20% hills around his house compared to derailleur.
Another suggestion: bring it to Redbridge next month.

But the Eiger has the same motor as the Woosh that he has already rejected ,so what would be the point?
Now what would be a good idea is to let dmsims have a ride on the Kudos Tornado,as he has owned a Woosh CD,that would be an expert comparison. Dmsims........what is your location I have a number of new dealers who have a Tornado for testing,you will be amazed!
I can't go to Redbridge,will be out playing boats at that time but I wish Hatti all the luck with the Woosh day.
Whilst we are on the subject of shows,Kudos will be repeating its Redbridge show April/May next year,Although Kudos pioneered this show at such an excellent venue,it really does need good and expensive promotion to get an adequate footfall.

 

[trex]

I never find the power of any BPM motored legal bike to be excessive,if what is being sold by my London Dealer is typical it is taking the lion share of the mid range priced product.
Obviously any right thinking person would think that a 40 mph bicycle ridden by a 14 year old on a seafront or bridleway would be stupid.
I know I am going to regret asking this.....but what is BBS02?
What will bring this all to a head is the current sellers of mopeds and scooters,which are clearly the 500-800 watt bikes that I see millions of in China,they weigh 50-90 kilos and are very powerful.
The sellers claim all the usual no tax,mot,helmet,registration....but they also say that can be ridden by 14 year olds and you can refuse a blood test or breathalyser test....I read into that that their market is drunken 14 year olds who want to legally terrorise pedestrians. There is one advertising on this forum,is this a Pedelec ?
KudosDave

I agree that the power of the BPM is not excessive on 36V when you weigh 18st and have to face a big hill. But if the BPM is allowed, on the strength that instant power does not count, only the label does, then what stops somebody to label the BBS02 'Nominal rating: 250W'? The BPM can deliver about 43% more instant power than the TCM with the same battery kit but the BBS02 give 100% more. The BPM can take 48V while the TCM can't. You need to see the madness of this, dave.

But the Eiger has the same motor as the Woosh that he has already rejected ,so what would be the point?
Now what would be a good idea is to let dmsims have a ride on the Kudos Tornado,as he has owned a Woosh CD,that would be an expert comparison. Dmsims........what is your location I have a number of new dealers who have a Tornado for testing,you will be amazed!
I can't go to Redbridge,will be out playing boats at that time but I wish Hatti all the luck with the Woosh day.
Whilst we are on the subject of shows,Kudos will be repeating its Redbridge show April/May next year,Although Kudos pioneered this show at such an excellent venue,it really does need good and expensive promotion to get an adequate footfall.

The point is to compare the efficiency of the NuVinci against the derailleur on a challenging terrain.
Both bikes have about the same motor and Lishui controller, so it's down to NuVinci versus derailleur.
I predict that the NuVinci will waste about 10% extra energy on 15% gradient through shearing of the oil surface, it will also lock up and can't shift under heavy rider weight, totally inferior to the efficiency of a derailleur on first gear.

 

[Kudoscycles]

I doubt it could be the future since the concept has a fundamental flaw in the intrinsically hybrid e-bike field.

Electric motors for legal e-bikes only need two gears, or by a stretch three, to adequately cover the road speed range at near maximum efficiency.

Cyclists need many more to maintain optimums of cadence and personal efficiency, especially in challenging territory. So a combined gear system will always compromise one or the other.

The nearest we ever got to a solution to this conundrum was the Swizzbee, a motor driving one side of a form of wheel hub differential, the rider's derailleur driving the other side. The output into the wheel was the sum of the two inputs differentially adjusted.

But Tony,don't you think that many (note not all)of these electric bikes are now bought as mini mopeds.
A day out in an e-bike dealership is a eye opener. So many customers don't want to pedal,want to go everywhere up to 28 mph,want to ride down cycle tracks,want a throttle,don't want tax,insurance,helmet,cost less than £1k...I would say that represents 40 per cent of the market.
Ideal bike for them is a cheap S class bike with a throttle .
Not much to do with cycling!
Regards
Dave
!

 

[Kudoscycles]

I agree that the power of the BPM is not excessive on 36V when you weigh 18st and have to face a big hill. But if the BPM is allowed, on the strength that instant power does not count, only the label does, then what stops somebody to label the BBS02 'Nominal rating: 250W'? The BPM can deliver about 43% more instant power than the TCM with the same battery kit but the BBS02 give 100% more. The BPM can take 48V while the TCM can't. You need to see the madness of this, dave.

You didn't tell me what the BBSO2 is?
So I cannot answer your question of whether it is madness.

 

[trex]

just google 'bbs02'
Here is a quick review:

http://www.electricbike.com/bafang-bbso2-750w-mid-drive/

 

[flecc]

But Tony,don't you think that many (note not all)of these electric bikes are now bought as mini mopeds.
A day out in an e-bike dealership is a eye opener. So many customers don't want to pedal,want to go everywhere up to 28 mph,want to ride down cycle tracks,want a throttle,don't want tax,insurance,helmet,cost less than £1k...I would say that represents 40 per cent of the market.
Ideal bike for them is a cheap S class bike with a throttle .
Not much to do with cycling!
Regards
Dave
!

Fully agree when we're speaking of UK customers, and it's long been true.

Back in 2003 when A to B magazine was critical of the very low pedal gearing on Thompson's e-bikes, making pedal assist at over about 8 mph impossible, Thompson senior retorted, "Our customers don't pedal, won't pedal".

But as Trex remarked earlier on the potential for the BPM, European customers (mainland) see things differently. Since that's by far the bulk of the market, design has to be predominantly for there. The large markets of The largely flat Netherlands and Denmark don't need either BPM power or motor gearing, and Germany already has higher speed and power classes.

The rest of the EU market is of little more consequence than ours, being very fragmented in what is wanted.

 

[Kudoscycles]

The point is to compare the efficiency of the NuVinci against the derailleur on a challenging terrain.
Both bikes have about the same motor and Lishui controller, so it's down to NuVinci versus derailleur.
I predict that the NuVinci will waste about 10% extra energy on 15% gradient through shearing of the oil surface, it will also lock up and can't shift under heavy rider weight, totally inferior to the efficiency of a derailleur on first gear.[/quote]

Trex.....please for once,give me a straight answer.....how do you know that the Nuvinci locks up and can't shift under heavy rider weight?
Quote...'I predict that'.....have you been off to the clairvoyant on Southend pier?
KudosDave

 

[Kudoscycles]

just google 'bbs02'
Here is a quick review:

http://www.electricbike.com/bafang-bbso2-750w-mid-drive/

Trex,i just don't get your point,that says 750 watt motor,is it Woosh intention to sell such a motor?
If you put a 250 watt sticker on a 750 watt motor I would suggest that madness is perhaps not the right word,maybe stupid and dishonest would be more appropriate.
Maybe just splitting semantics.
KudosDave

 

[trex]

you should google more, dave.
google 'customers reviews of the NuVinci N360'.
You won't find much compliments for the system.

Here are a couple from amazon customers. They were enthusiastic when they bought it, then less and less over time.

http://www.amazon.com/NuVinci-N360-rear-hole-black/product-reviews/B003RLA3KG

...
Turns out that there was a very slow leak of the N360's internal fluid on the disk brake side rendering the disk brake almost useless. The fluid had a greenish cast that I noticed, when the bike was stationary for a week, on the bottom edge of the brake disk. I called Nuvinci and they determined it was a leak and sent a replacement wheel to the bike store I bought the bike from and replaced it free of charge. Leak is gone and rear braking power has returned.

...
If you are used to a trigger shifter, forggetabut this one. Next, grip crap started binding and cable popped out of the plastic housing. afterwards, couldnt shift over certain points. when the grip crap was working, this nuvinci i got wont shift all the way in the range unless you move the bike. shift adapter would stop half way from extreme low or extreme high. Shift adapter is really badly made. It wobbles and bends on pressure from cables. Hey fallbrook, who approved the final production prototype? certainly not someone who used it.I can guarantee it. Finally had to chuck the grip crap and adapt (A.K.A headache) the sram x4 shifter with a spring attached to other cable. For the 600 or so i got into this, wish i had gone with a Shimano Alfine instead. Oh well, live and learn i guess. For the next one, would definitely go with a shimano. This one is too much mcgyvering involved to work right. Hope fallbrook CEO reads this and get busy.

update: shift adapter grabs badly while trying to shift. sometimes it moves freely, sometimes grabs badly. going in the garbage. what a f*** **** off this is.
Update: got a alfine 11 put in. Difference: very low rolling resistance, quick shifts,ability to remember sweet points and a hell of lot lighter. Nice try fallbrook. If i were you, dump the ball setup and try to figure out how to make a sliding spider gear setup to work. its my mistake, n360 is the later version.

 

[Kudoscycles]

Fully agree when we're speaking of UK customers, and it's long been true.

Back in 2003 when A to B magazine was critical of the very low pedal gearing on Thompson's e-bikes, making pedal assist at over about 8 mph impossible, Thompson senior retorted, "Our customers don't pedal, won't pedal".

But as Trex remarked earlier on the potential for the BPM, European customers (mainland) see things differently. Since that's by far the bulk of the market, design has to be predominantly for there. The large markets of The largely flat Netherlands and Denmark don't need either BPM power or motor gearing, and Germany already has higher speed and power classes.

The rest of the EU market is of little more consequence than ours, being very fragmented in what is wanted.

Flecc......Holland is almost a unique market,they are very traditional in their likes and in fact the very first of the bikes I bought over from China are still their choice,hill climbing ability obviously not a priority.
But Germany,Austria and Switzerland are a different matter,KTM had big problems with Bosch deliveries last year so are having a big push in those countries but using the Panasonic hub motor.
They are trying to create a range of bikes which call upon the heritage of KTM motorbikes,which are very exciting bikes. I think they want the KTM electric bike range to echo that character.

 

[trex]

Trex,i just don't get your point,that says 750 watt motor,is it Woosh intention to sell such a motor?
If you put a 250 watt sticker on a 750 watt motor I would suggest that madness is perhaps not the right word,maybe stupid and dishonest would be more appropriate.
Maybe just splitting semantics.
KudosDave

I am saying that there is a difference between nominal power (what's on the label) and instant power (what's coming out of the motor). The BPM dishes out 43% more power than the TCM can, at its maximum power on the same bike. If the manufacturers continue along the path of the Pana hub (47V 20A), then why not the BBS02 (47V 20A) ? If you feed the BBS02 with 47V 20A, it is so efficient at pulling bikes on flat roads that you can hit 40mph, at that speed, accident will be fatal. So instant power needs to be limited by law. Then you see that the TCM and SWX may be legal and the BPM and P hub not. At least Bafang are honest at labelling the BBS02 as 750W.