If you are going to fit a crank drive, you would lose the chainring, saving a little weight. I was thinking of using a 2kg saddle bag battery (10s3P with Panasonic 3400mAH) - the whole bike should weigh under 15kgs with a 35 mile range.
Very lightweight e-bikes
- Thread starter Kudoscycles
- Start date
C
Cyclezee
Guest
A couple of contributors to this thread need to 'lighten up a bit', Flecc isn't one of them. That's my opinion.......for what it's worth.
Everyone is entitled to their own opinion without getting the third degree.
Everyone is entitled to their own opinion without getting the third degree.
Col, I don't wish to know what is clearly wrong. When road cyclists, including commuters, who have suffered more than one breakage on light road bike frames, solve their problem by switching to other types of heavier frame for that same use, that is clearly in conflict with what you appear to be insisting.
Maybe you are comparing apples and oranges, as one example, MTBs being used in very different conditions and in consequence suffering as many breaks as road bikes on the road. That's not what I'm saying.
Maybe you are comparing the total of broken frames on other types to the total on road bikes, not taking into account the very different numbers sold. That would be a misuse of statistics.
But if you are insisting the failure rate in consumer hands of any other frame type is as high or higher than light road bikes, then I do not accept that and we will have to agree to disagree.
A crank drive is the only option on a carbon road frame with 130mm rear dropouts, but I just don't fancy losing my compact chainset.. There will be new carbon frames coming this year with 135 dropouts to accommodate 11speed cassettes with disc brakes, so will also fit a Keyde motor.
This to me is the best current solution for a lightweight road bike........using the tiny keyed bottle battery and depending on how much you want to spend on components you could achieve anything between 10-11.5 kgs.
Plus the fact the motor is hidden behind the cassette and disc rotor, so nice and stealth !! .........at least from the side
A 2kg saddle bag battery pack sounds good, but I'm clueless about batteries.
Perhaps you can elaborate for me.
Could I have half the weight for half the range.?....ie 1kg for 17 miles.
and how would you put it together ?
Bill
I would email XOFO and ask them to make it for me with their saddle bag pack. El Champiero posted on another thread http://www.pedelecs.co.uk/forum/threads/aftermarket-non-genuine-bosch-battery-received-for-testing.17021/ Fine Dragon Technology may do bespoke batteries. It's not advisable to reduce the number of cells to reduce weight.
Lion-ion batteries work best at 2C max discharge current.
You'll need 20A when climbing hills, the minimum capacity should really be 36V 10AH to avoid stressing the battery. BTW, jerrysimon uses the keyde motor mainly on flat roads and legal speed, I ride usually at around 20mph on flat road, guess it rules out the keyde kit.
Lion-ion batteries work best at 2C max discharge current.
You'll need 20A when climbing hills, the minimum capacity should really be 36V 10AH to avoid stressing the battery. BTW, jerrysimon uses the keyde motor mainly on flat roads and legal speed, I ride usually at around 20mph on flat road, guess it rules out the keyde kit.
Last edited:
will summarise my position in the hope you can see where I’m coming from, because as much as I do like a good forum debate, we are going round in circles now a bit, and my dinner is nearly ready J
You said this:
However you’ve now changed your stance, and are saying something that I and I’m sure no one else could argue with.
So now we can agree I hope J
I’ll make a comment about lightweight eBikes.
I think that eBikes will get down to a certain weight maybe 18-19kg ish and then not go much lighter, once they get to that weight people seem to be pretty happy with them and they can be reliable and not puncture on every hole in the road etc etc. What I think will happen is that the range will keep going up for a given bike weight. The push seems to be getting more miles per kg rather than just getting lighter for the sake of it.
I can’t see the point of a eRoad race bike. Road bikes roll so quick and the tyres are so thin that slapping a e onto it just kills the point. Far better to have something a bit more stable and capable of handling the forces and knocks and gives a range that can go as far and as fast as a road bike.
Cheers
Col
You said this:
and this
which just simply aren’t true, and that’s what I was trying to say. Both those statements are incorrect. They might be your opinion, but your wrong. Just like it could be my opinion that the world is flat, but I’d be wrong.
However you’ve now changed your stance, and are saying something that I and I’m sure no one else could argue with.
this is of course correct…. If some buys a heavier / stronger / better bike its of course going to last longer.
So now we can agree I hope J
I’ll make a comment about lightweight eBikes.
I think that eBikes will get down to a certain weight maybe 18-19kg ish and then not go much lighter, once they get to that weight people seem to be pretty happy with them and they can be reliable and not puncture on every hole in the road etc etc. What I think will happen is that the range will keep going up for a given bike weight. The push seems to be getting more miles per kg rather than just getting lighter for the sake of it.
I can’t see the point of a eRoad race bike. Road bikes roll so quick and the tyres are so thin that slapping a e onto it just kills the point. Far better to have something a bit more stable and capable of handling the forces and knocks and gives a range that can go as far and as fast as a road bike.
Cheers
Col
Yep providing your batteries can deliver sufficient currrent (only about 6 or 7 amps needed for a Keyde motor) without voltage sag. I run with 1kg, 36v, 3.0Ah batteries that will give me 10 miles in cambridge on my Brompton fitted with a Keyde motor. I also have a 2kg, 36v, 6Ah battery that will give you more miles in a hillier terrain. Not really available commercially, I built these batteries on a DIY basis.
Jerry
Last edited:
I'm sorry if there is a misunderstanding, but there wasn't a change of stance, I was always speaking of like for like use. The point was always about road bikes, used on road of course, so any comparison I made was for that use, emphasized by my expressed lack of interest in some other types. Perhaps I should have clarified that point.
In my London fringe area mountain bikes seem to be used almost entirely on-road, so I tend to forget usages elsewhere.
I completely agree with this Col, reliability, freedom from punctures and good range are all more important to customers than the last vestige of weight saving. True as much for leisure riders as for commuters.
D
Deleted member 4366
Guest
I came to this thread late. I am looking for a lightweight reliable e-bike, preferably MTB style, and I believe current bikes are about 5kg overweight even without carbon frames. I don't see why something like a typical hardtail Haibike needs to be well over 20kg . Once they get more mainstream and the volume high end manufacturers come in the weight will fall off and there seem to be several major technical breakthroughs coming on battery technology as well, especially from companies like Tesla. When we get rid of the Bosch stranglehold and introduce battery competition there will be major price and performance gains.
'lightweight' and 'reliable' are trade-offs. You can of course throw money at it but I don't think mainstream manufacturers are going to be bothered with pushing the envelope in that direction. The motor if anything enables steel frame bikes to be good contenders for high mileage commuter bikes.
Earwig,it is possible to get an 8 Ah battery down to 1.5 kg and the basic bike to about 10kg,without resorting to exotic materials. But a good motor is about 3.5 kg and then we want to add mudguards,lights,carry rack,panniers and soon you are back to 20kg. A step thru frame has to be heavier to achieve satisfactory stiffness,this adds 3kg.
I don't think any of us want to go below 8Ah battery capacity( 20-25 mile range),the basic bike weight of 10kg could be trimmed to 8kg by using expensive materials(if we are prepared to pay the cost). The lightweight motors that are around are produced by small suppliers and the reviews of reliability are mixed,it needs someone like Bafang to mass produce a reliable lightweight motor,perhaps 2 kg is possible. But are we prepared to give up mudguards,lights,racks to save weight.
Are we prepared to loose the hill climbing ability of the BPM motor to save say 1.5 kg weight? Are we prepared to pay £500 more?
A 15kg e-bike is possible but is it a nicer bike than a 20kg bike with all the features most customers seem to want....bikes are all about compromises and choices
KudosDave
Earwig is misguided if he thinks there will be significant leaps in battery technology within a few years.
When the battery was invented more than 200 years ago it was big and heavy.
The same is still true today.
Go figure.
When the battery was invented more than 200 years ago it was big and heavy.
The same is still true today.
Go figure.
Earwig,I have a new bike due out soon,it's just a bit early to release full details,it will be named the Rapide.
I took a nice lightweight sports bike frame,added hydraulic brakes,Bosch style lightweight 11 Ah battery,BPM motor,lightweight full radius mudguards,lightweight rear rack,lightweight led lights. I was very careful to check every gram that I added to the bike without resorting to exotic materials,I don't think any element is over engineered but I couldn't get the weight below 20 kilos. To get down to 15 kilos you have to sacrifice hill climbing ability,drop the range down to less than 10 miles,have nil accessories,no lights,no mudguards.....this is not the bike most customers want as daily practical transport.
The Rapide will be priced at £1395.00,all Kudos dealers have draft information and spy type photos.
KudosDave
Colin,I agree about your point about a road race e-bike it seems to all of us at Kudos that it's a conflict in terms. If for example you took a 7 kg Bianchi style carbon frame bike with drops,added 10 kg electrics,you change the whole character and performance profile to such an extent that the end result would no longer appeal to a road race type customer.
Sort of like buying a Porsche and use it for carrying bags of cement around.
Having said the foregoing I still find it interesting to manufacture an e-bike version of the McLaren Specialised S-Works or the Haibike Pro Race,great flagship bike but who would buy one?????
KudosDave
you could squeeze the electrics (including 36V 10.4AH battery) in a CD kit to under 5kgs.
Related Articles
-
MTF Enterprises announces acquisition of EMU Electric Bikes- Started by: Pedelecs
-
Wisper 806T folding bike wins Which? ‘Best Buy’- Started by: Pedelecs
-
Sustrans calls for protected cycle lanes- Started by: Pedelecs
-
Amazon launch their first UK e-cargo micromobility hub- Started by: Pedelecs
