Author Topic: E bike plus frame  (Read 470 times)

gido

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E bike plus frame
« on: October 14, 2017, 03:27:32 PM »
Looking for X large ebike carbon frame that fits bafang mid drive motors. I found only this http://m.dengfubikes.com/index.php?s=/192.html



Sitar_Ned

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Re: E bike plus frame
« Reply #1 on: October 14, 2017, 07:32:55 PM »
I'm interested in this as well, if anyone has any info. Really interested in ebikes and am hoping to see a growing number of choices in chiner ebike frames. If you build one, please post a build thread.. I'd love to get an ebike section of the forum going.

Gido, is the bafang motor one that you own or plan to buy? Would you say it's the best bang for your buck? I literally just started looking into ebikes a couple of days ago so don't know much about the motors.

Thanks, and welcome to the forum btw.


gido

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Re: E bike plus frame
« Reply #2 on: October 15, 2017, 03:03:40 PM »
Thanks Sitar_ned,
I will post a tread if I find a suitable frame for my build. Bafang is the undisputed king for DIY ebike community(BBS series) and best bang for your buck. Their new generation motors with integrated tourqe sensor are on par with big players Bosch, Shimano, Brose, Yamaha...and have many advantages in price, throttle option, DIY battery, open software, more power, easy availability. We just need modern geometry quality frames with short chain stay, boost rear spacing, intube battery space...then we can build excellent DIY ebikes :)




Sitar_Ned

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Re: E bike plus frame
« Reply #3 on: October 16, 2017, 08:44:46 PM »
Thanks Sitar_ned,
I will post a tread if I find a suitable frame for my build. Bafang is the undisputed king for DIY ebike community(BBS series) and best bang for your buck. Their new generation motors with integrated tourqe sensor are on par with big players Bosch, Shimano, Brose, Yamaha...and have many advantages in price, throttle option, DIY battery, open software, more power, easy availability. We just need modern geometry quality frames with short chain stay, boost rear spacing, intube battery space...then we can build excellent DIY ebikes :)

Ah, okay.. So the motor tech is there and affordable we're just waiting for some frame options. Well, hopefully the demand is enough to make that happen.

Thanks for the info.

Sitar_Ned

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Re: E bike plus frame
« Reply #4 on: October 16, 2017, 08:47:24 PM »
Oh. Just checked and the bafang is a touch over $700.. a bit higher than I expected it to be. I was guessing $400ish

« Last Edit: October 16, 2017, 09:20:24 PM by Sitar_Ned »

Peter60

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Re: E bike plus frame
« Reply #5 on: October 24, 2017, 04:59:04 PM »
Is there any experience with the E bike carbon frame from Ican (or Imust):
http://www.icanbikes.com/html/MTB/E_bike_series/355.html

What do you think about this proposal?

Sitar_Ned

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Re: E bike plus frame
« Reply #6 on: October 27, 2017, 10:11:32 AM »
After a bit of research, it seems ebikes are mostly limited to 20mph due to US laws. While I think that's acceptable, I would prefer it be 30mph at least. I would think you could build up a pretty stout ebike with fat rims that would remain stable at pretty high speeds. Hell, road cyclists get over 40mph on those skinny ass wheels. Luckily, it seems there are ways to bypass the manufacturer's speed limitations on some models. I'm sure within a couple of years the options will open up even more, and as battery technology / electric motor tech progresses.. I think ebikes are shaping up to be pretty interesting indeed.

mezastel

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Re: E bike plus frame
« Reply #7 on: October 30, 2017, 11:19:23 AM »
I have extensive experience with ebikes, so let me add a few subjective thoughts:

  • You don't need a carbon frame on an ebike. In fact, I would advise against it due to the higher stresses on an ebike's rear wheel. Steel - heavy steel - is just fine. I mean one of my ebikes is 27kg and I don't care - why should I, it's an electric bike. And no, getting it up the stairs isn't a problem.
  • Comparing factory bikes with Bosch/Yamaha systems and Bafang is like comparing BMW and a Lada. Factory systems feel solid and safe, Bafang is a random chinese factory experiment where key features such as pedal assist are an afterthought.
  • Bafang does not have a torque sensor. This is a critical feature in an ebike and not having it means your Bafang-equipped bike is essentially a moped that has no idea how much torque you need at a given time. Makes the bike harder to drive and a lot less safe!

If you do decide to go for a Bafang, I would recommend a fatbike rather than a plus bike because, honestly, it doesn't matter and the fat tyres will give you even more comfort. Remember -- weight doesn't matter at all.

Another recommendation -- don't install a derailleur. I used to have derailleur-equipped ebikes, then I got one with Rohloff 500/14 and OMG I will never have a derailleur on an ebike ever again. There's just no point! Also, remember ebikes can wrap a dirty chain around the motor when you have enough slack, well, with a hub gear your chain doesn't move anywhere -- it's stretched to maximum, so you're never at risk of chewing it up. I had so much trouble with this!

Let me know if you have any more ebike questions :)

Sitar_Ned

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Re: E bike plus frame
« Reply #8 on: November 07, 2017, 10:08:23 AM »
Thanks for the input, mezastel... good info.

I'm a little confused though as to why you would disregard total weight when building an ebike though. I understand your point about needing addition strength, and I haven't looked into it but I had assumed carbon would be plenty strong enough. Evidenced by the current carbon fiber ebikes on the market, right?

Personally, if I was buying an ebike (and I may within a couple of years) I would absolutely care about the weight and would make efforts while doing the build to keep it fairly lightweight. I mean, wouldn't the weight directly affect the effectiveness/efficiency of the battery? Also, I was under the impression that you can pedal an ebike when not using the battery power.. the weight would certainly matter, it seems.

mezastel

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Re: E bike plus frame
« Reply #9 on: November 24, 2017, 01:34:07 PM »
The weight of the ebike has marginal effect on the efficiency of the battery. Most of the energy goes into acceleration, not into actual maintaining of speed. What an ebike give you is an ability to very quickly accelerate from stationary position. I have ebikes of different weights, from 16 to 27kg and I see no difference in battery consumption. Ultimately, the weight of the bike is marginal compared to my weight (77kg) so a +/- 10kg change in the weight of the bike only translates to just around 10% total weight saving. It's just not worth it.

Some of the things you can have as a result of "f~k weight economy":

  • Install a heavy planetary gear hub such as Rohloff or NuVinci
  • Install a rack and put a load on it. I use the rack to take my son to school (30kg)
  • Use heavy 1.5mm bicycle tubes; this is puncture protection at the cost of extra weight

Honestly, I wouldn't worry about weight unless of course you go for carbon. Carbon doesn't take the stresses so well, not to mention that any direct impact has a chance to just break it. With carbon, perhaps you do need to calculate weight. And I do know that carbon ebikes exist, but they mainly exist because they are commuter folding bikes that you need to be able to pick up. Most ebikes are too heavy to pick up, which is why manufacturers add Walk Assist functionality so you can get them easily up the stairs.

About pedaling the ebike when not on battery power. On Yamaha: yes, doable. On Bosch: no way; the front sprocket is too small to make pedalling comfortable. And if you go for a gear hub, well, that makes things even worse: pedaling a Rohloff without assist is possible, and if you run out of power you can do it for short periods of time, but it's not very efficient and you won't go fast. You should be OK pedaling on a Bafang, but I haven't tried it myself so I cannot say for sure; Yamaha bikes have large front sprockets so it's not such a big deal there.