Very lightweight e-bikes

[flecc]

You have to be careful drawing conclusions from any statistics. The reason they break might be because they crash more since they're often used for racing and riding at the limit of tyre adhesion.

You really are desperate! You've seen the links, four frames broken by a commuter and occasional weekend rider. Three by another with no mention of any untoward events, and his change to stronger frames stopping the problem. Several posting about the need to avoid undue stress from riding techniques, something not at all necessary with other bike frame types.

And the last contribution to example 7 giving lives to his use of frames from experience, aluminium 9 to 12 months, steel TIG welded 18 to 24 months. And once again he solved his problem by changing his bike type to rugged frame 29er mountain bikes, proving beyond any doubt that the road bike frames are much more vulnerable, nothing to do with accidents.

You've always made clear your preference for moderate cost sprung bikes, even including full suspension, disc brakes etc, nothing remotely relevant to the road bike scene. I really don't think you have any knowledge of this subject, and unlike me, never posting anything about the road and race bike scene until choosing to pick this argument.

I've posted my opinion with supporting information, you've posted your opinion. Why not leave readers to make their own minds up?

 

[jerrysimon]

Just to add that I have had very good success with the use of Tongxin/Keyde motors on small wheeled bikes and on flatter terrain based in Cambridge. Having fitted about a dozen now (primarily on small wheeled bikes) I have only had one failure and that was not a failure in that it just started making a loud noise after 1K of use. I was never able to track down the problem.

I did convert my daughter's Mountain Bike (26" wheel) adding a Tongxin motor which she used with no failure for two years. She has M.E and added very little assistance. Again though like me used primarily on flatter terrain in and around Cambridge. That has been sat in my shed for the last six months since I purchased her a bespoke ebike cheap from Halfords

It is clear that Tongxin/Keyde motors have their place and are better suited/more reliable in certain applications. I would suggest for small wheeled bikes in flatter or hillier terrain. I also think it very important to keep the current down on these motors.

As per my other post I am planning on trying both motors on a hybrid full sized bike but again in and around Cambridge.

PS just to plug my 11.5kg Ti Brompton

M2LX with a front Keyde motor.

Jerry

 

[KTM Bike Industries UK]

I made clear that my mention of suspension was a guess since I have little relevant experience.

It's facile to pretend that bike weight reduction efforts are similar for all bikes, they clearly are not. It's on the lightest road bikes bikes that they are pushed to the limit. I repeat, the frame failure rates on very light road bikes are far, far higher than on any other type of bike.

I'm not sure how can you say you don't know about one massive part of the industry but then in the same breath make a sweeping statements about the whole industry.

And yes, they are.... we're a brand - there are 240 bikes in our range. The desire to make bikes lighter is pretty much equal across the range and our customers are just as demanding about weight be it a mountain bike, a road bike, a city bike or an eBike. There is no difference.

Cheers
Col

 

[trex]

recipe for under 15kgs e-bike:
Buy this 8kg carbon road bike from Rutland cycles for £675, add a $400 kit then you have a very light weight ebike. Why the drama?

 

[flecc]

There is no difference.l

There is, it's as I've said throughout, in the results.

Other types of bike like MTBs, mountain bikes and utility bikes don't suffer the frame failure rate of the lightest road bikes. Clearly their weight saving measures are not pushed to the low level of safety margin that road bike frames are in order to minimise weight.

I say to you as I've said to Dave, I've posted my opinion with supporting information, you've given your opinion, so let's leave it to readers to decide who they believe.

This thread was posted by KudosDave asking for members opinions. I gave mine. There was and remains no justification for the attack on my opinion. Others contributions should have been solely their own opinions, leaving KudosDave to decide from all the responses.

 

[flecc]

recipe for under 15kgs e-bike:
Buy this 8kg carbon road bike from Rutland cycles for £675, add a $400 kit then you have a very light weight ebike. Why the drama?

Agreed, no drama on this account from me. I questioned the alloy frame 11 kilo Annad durability, 15 kilos all carbon based seems more reasonable to me.

 

[KTM Bike Industries UK]

There is, it's as I've said throughout, in the results.

any chance you can send me a link to these statistics / results as I've never seen any brand in the bike industry publish anything.

I can give you the details of all the road frame failures from KTM in the past two years in the UK, as an example..... There is only one road bike related one, and thats because the rider hit the back of a car he was tailing and snapped the forks. We've not had a single road bike frame fail.

Other types of bike like MTBs, mountain bikes and utility bikes don't suffer the frame failure rate of the lightest road bikes. Clearly their weight saving measures are not pushed to the low level of safety margin that road bike frames are in order to minimise weight.

this is just wrong I'm afraid, and this is true for every brand I've got experience of and in every shop I've worked in or visited. Most high end road bikes are ridden by people who don't push them anywhere near the limits they are designed for, mountain bikes on the other hand get ridden in appropriately all the time, and as such the failure rate is higher.

The weight saving measures are pushed just as far for every type of bike, and in fact in MTB (MTB stands for mountain bike) there are no legal limits for what can be raced so they push things further than road and as such failure rates are higher.

 

[flecc]

any chance you can send me a link to these statistics / results as I've never seen any brand in the bike industry publish anything.

I was quoting from the online links I provided earlier, not industry statistics. That post was to d8veh to show that these lightweight frame breaks occur, following his statement that the idea that they break was "ridiculous".

I've asked you to respect the original thread intentions and the intent of my expressed opinion. I add that you made no contribution of an opinion for the OP, entering the thread solely to attack my opinion, not for the first time I must say.

I prefer to enter this forum to help others and add interest where possible, as I've just done for a couple of others. Perhaps you could do the same with advantage?

 

[103Alex1]

then there is only one practical solution for very light weight bike: crank drive.

I agree in principle - that's why the Vivax was attractive, but the cost and maintenance are so disproportionate as to make the whole proposal a non-starter.

The other crank drive solutions just seem far too rough and ready to be compatible with what one would be trying to achieve.

I am still keeping an open mind, but at the moment just can't see that lashing a monster of a BBS-01 to a carbon road bike makes any kind of sense (hence interest in the Keyde).

 

[KTM Bike Industries UK]

those on-line links don't really mean anything much, its possible to find things on the internet to back anything up if you search. Industry statistics is what you really need.

do you have any idea how many lightweight road bikes are sold in the UK? although I'm not sure what you count as lightweight? But do you have any idea? or any idea what % of this category you think fail?

and then how does this compare to other types of bikes, how many do you think sell of those types, and how many of them fail?

so as you don't have the numbers to back up your opinions its probably not worth me trying to help give you some information to help you understand whats going on across the industry.

So just to show some things about testing carbon bikes, this is worth a watch

..... why is it so hard to share links? What am I doing wrong????

Cheers
Col

 

[flecc]

those on-line links don't really mean anything much, its possible to find things on the internet to back anything up if you search.

You just are not getting it are you, so I repeat my last two paragraphs in the hope that you understand:

I've asked you to respect the original thread intentions and the intent of my expressed opinion. I add that you made no contribution of an opinion for the OP, entering the thread solely to attack my opinion, not for the first time I must say.

I prefer to enter this forum to help others and add interest where possible, as I've just done for a couple of others. Perhaps you could do the same with advantage?

I'm not interested in a protracted argument on this or any other subject, it's not my purpose for being in this forum. Your opinion could have been expressed to the OP without choosing to attack another member's opinion instead.

 

[Deleted member 4366]

You started it, Flecc by implying that the Annad frame isn't strong enough for a motor. You expressed concern about the strength of the frame in posts #35 and #65. and each time i try to allay your fears, you argue the point. there's no facts anywhere that show that the Annad frame is not strong enough. Its just a figment of your imagination based on some broken frames on totally different bikes. You've no idea what material Annad use in their frames, how they heat treat it, how they weld it, or what are the actual stresses there are in the frame. I find it ridiculous that you think that the Annad frame is not strong enough not that you have experience of frames breaking. It's the way you jump to conclusions without the relevant facts that I object to.

"I'm not interested in a protracted argument on this or any other subject, it's not my purpose for being in this forum"

Come off it, Flecc. Every time somebody disagrees with anything you say, you argue it to death - just like this one.

 

[flecc]

to.
Come off it, Flecc. Every time somebody disagrees with anything you say, you argue it to death - just like this one.

And you don't!!!!

I expressed my doubts about an 11 kilo alloy frame e-bike in direct response to a request for opinions from the OP. He didn't ask you to start an argument, you could have been content to answer the OP by expressing your own opinions about the bike without directly targeting me with disagreement. It's not your right to make the OP's decision and he didn't ask you to do that.

I did not start this dispute by giving my opinion to the OP, you did by attacking my view, and that is what has always happened in every dispute we've had. If in future you confine yourself to giving your own views in posts instead of looking for an argument, I won't have any cause to argue my position, no matter how different your views are to mine.

I respect the right of others to have a different opinion, you don't seem to as your often aggressive responses show.

 

[Artstu]

Just the job for one of those light rear hub motors.

http://www.bikeradar.com/road/news/article/taipei-cycle-show-swiftcarbon-debuts-sub-700g-sculp-road-frame-40251/

 

[Kudoscycles]

Oh dear,come on guys lighten up (no pun intended,honestly!)...I go away from my posting for a few hours and all hell breaks loose. There is clearly an appetite for light weight bikes but at the moment I dont think the supporting parts are there to achieve it. My thoughts are-
The frame can be ally,these modern ally frames are only about 1 kg heavier than a carbon frame,it is easier to mount parts to ally and they are less costly
The Keyde/Tongxin type motor I just dont have enough confidence to commit to volume production...I know some customers have good results,some bad....it is ok if you are making a one-off but volume production has so much more responsibility.We need a bigger motor manufacturer that can achieve the performance of the BPM motor with a weight about 2 kgs,I think it will happen but not now.
There is not a battery with 10Ah capacity about 2kgs weight and there doesn't seem to be an imminent breakthrough. Battery manufacturers keep appearing with claims of quicker charge,longer life,lighter weight but they dont seem to make it into production.
If the foregoing happens I think a nice and strong e-bike can be produced about 14-15 kgs,based upon a donor vanilla bike of about 9-10 kilos,but 11-12 kilos is just too light-unacceptable compromises have to be selected that make the bike impractical.
I am off to the Shanghai show in April...there are always 50 plus battery manufacturers and many motor/controller suppliers with new product...perhaps something new will make such a lightweight bike an affordable reality.
In the meantime my Cobra/Arriba/Escape/Tornado/Typhoon series at about 20-21 kilos is as light as possible using a good motor and 10Ah battery.
thanks for everyones input,this posting is obviously of interest to many,considering the time it has stayed at the top and the number of viewing and postings. Lightweight with power and range is obviously the future.
KudosDave

 

[Geebee]

The Reef bike and I assume therefore the Annad are Alloy frames with a carbon fork, so not a super light full carbon job, and Reef seem to think the frame will last.

"Your Reef invisiTRON R1 electric bike is covered with a Comprehensive Warranty on all parts including a 3-year warranty on the frame and 1-year on the battery, motor and the electrics. We are confident that your electric bicycle will have no problems during the warranty period."

Yes treatment is a factor, we had a down hill comp locally and the interstate competitors (the more polite ones) said the track was technically challenging.
The amount of broken bikes over the day was horrifying, and I mean broken as in at least 2 seperate peices and these were bikes designed for downhill.
There will always be broken frames no matter how they are built but a road bike treated as a road bike can last even when relatively light weight.

 

[Arbol]

There is not a battery with 10Ah capacity about 2kgs weight and there doesn't seem to be an imminent breakthrough. Battery manufacturers keep appearing with claims of quicker charge,longer life,lighter weight but they dont seem to make it into production.

Are you sure? 40 cells of Panasonic PF make a 36V11.6Ah. Each cell weights less than 50g, so the total is less than 2kg. BMS barely adds weight.

 

[Deleted member 4366]

Indeed. Panasonic now have 3400maH cells that will give you a 13.6aH battery at 2.5kg including BMS and case, or you could have a 30 cell 10aH at about 1.8 kg, which would be OK for a light-weight low-power bike, but not enough current for a BPM.

Although we've not seen any step changes in battery technology, there's been steady improvement in discharge rates and energy density. A couple of years ago, when bottle batteries first came out, they were 8.8aH and struggled to give 10 amps continuous. Now, 11.6aH ones that can do 18 amps continuous are readily available, which is a 15% increase in capacity per year and about 35% increase in discharge rate. If that rate of improvement continues without breakthrough, in another two years we'll have 15 aH bottle batteries weighing 2.5 kg that can give 32 amps.

 

[KTM Bike Industries UK]

I've asked you to respect the original thread intentions and the intent of my expressed opinion. I add that you made no contribution of an opinion for the OP, entering the thread solely to attack my opinion, not for the first time I must say.

I prefer to enter this forum to help others and add interest where possible, as I've just done for a couple of others. Perhaps you could do the same with advantage?

I appreciate my comment wasn't directed at the original topic. However I did think your comments needed picking up on.

As such a valued, prolific and opinionated contributor to this forum, I'm sure many will read your posts and assume you know what you're talking about.

Whilst in many / most cases you clearly do. I'm afraid when you state opinions that aren't correct, I'm sure you have to expect someone who knows the facts to pick you up on them / help you. I wasn't trying to start an argument, I was simply trying to, as you put it:

enter this forum to help others and add interest where possible

If you don't want to learn more about the parts of the industry you have admitted to not knowing about thats fine. But please don't try to say I'm arguing with you, just because I entered this thread to try to help you understand things more clearly.

Regards
Col.

 

[bmc]

recipe for under 15kgs e-bike:
Buy this 8kg carbon road bike from Rutland cycles for £675, add a $400 kit then you have a very light weight ebike. Why the drama?

Certainly a very good price for a carbon road bike, but with sora groupset and the rest of the finishing kit, I would guess it's nearer to 9kgs than 8kgs.