'lightest.bike' 1.7kg 1000w mid drive

neptronix said:

Oh it has that thick grease huh..
I would be very unhappy about that drag and would want to convert it to an ATF bath immediately.

Because it has removable internals, there's a very small area on the hub where you could have ATF hanging out. Tilt the bike a few degrees and that ATF is coming out of the side seals so now you need to figure out how to make that not happen and make ATF spillage only happen out the axles which should be minor.

ATF would improve the efficiency and durability of the drive. We don't know by how much.

It's another science experiment to throw money into and i'm starting to get exhausted with this effort already.

My semi recumbent will do 37mph on 1200W and has two gearing stages so i have more than enough room to regear.
I'm trading gearing problems for mounting problems but i think those would be easier to cure with the lowest amount of compromises. I think that's the better route to go.

I've sent an email asking bikee if there are any other possible options. I'm not crossing my fingers.

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I still maintain that a compound chainring is your only practical option on the 26er. And you can test that without Bikee's involvement. Just disable the torque sensor and take it for a throttle only test ride with a 50/36 chainring setup. That should work with the existing firmware.

This is a very reasonable idea compared to all others explored and i'm okay with it being throttle operated full time, so why not..

I forget, did your throttle just work w/o the upgrade code you received?
Also do you know where i can get this throttle you have? is it just some standard bafang throttle that works on the BBSxx kits or what?

To enable the throttle you might need buy the Superhero DLC, the horse armor pack, unlock the rainbow hair colors pack, and the additional 25 lives pack.

But any bafang throttle should work. Here's the one I used with the Bikee kit:

Thinking about these IGHs.. many of them are heavier than this drive itself.. that's kind of sad.



The conversion cost would be similar in price vs an IGH but have a better result. But my bike's out of operation for a while.

Asking for a quote on this.

neptronix said:

Thinking about these IGHs.. many of them are heavier than this drive itself.. that's kind of sad.

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The conversion cost would be similar in price vs an IGH but have a better result. But my bike's out of operation for a while.

Asking for a quote on this.

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And loose-chained IGH installs suck because you have added the drag of the hub, but not removed the drag of the derailleur. So IGH are really best for single-speed frames, and that won't work with the Bikee kit.

Yeah i get that bit about the tensioner.
You are taking a ~3% hit even with a Rohloff and that kinda sucks.

Great points. Buying the lightest ever motor to pair it with a heavy hub is kind of backwards.

But honestly, I only think the lightness of this drive is relevant in eMTB applications.
Otherwise, the massive battery needed for range at speed will outweigh the ligness gains anyways.

Lightness and efficiency usually go hand in hand. If the motor is really somewhere in the 90% efficiency neighborhood then your battery needs are lower and you can chose to take advantage of that either by making the bike lighter or just enjoying the extra range. The weight differential doesn't matter that much in terms of range.

When you start overvolting a high efficiency motor the efficiency curve tends to have a really slow dropoff or even a gain. When we're at higher speeds this extra efficiency matters and allows us to push the motor a lot further than it's rating would imply.

This is the case with the Shengyi SX2. It's probably got razor thin lams and great stator construction. It's rated 500w but as you can see you can flog the absolute hell out of it. Probably for very long periods of time.



Similar case with the leafbike 1.5kw ( 90.5% peak efficient hub ) where the efficiency range is super broad, so running 6kw on it for a few miles here and there is no problem. A 82% efficient motor would melt fast in that same condition because we have additional 100's of watts of heat we didn't have in the 90.5% peak efficient hub.

The heat budget can be increased on this motor ... and we probably have a very broad efficiency range... so this is probably an ebike tuner's dream.

Versus something like a CYC Photon or BBSx where you are constantly fighting heat issues.. and part of that lower efficiency is due to thicker or poorer quality materials so you're for the most part stuck with stock power or close to it because as you add the volts, the efficiency goes down quickly instead of remaining flat or increasing.

The fact that it weighs 4.1lbs is just a bonus!

I somewhat agree.
If you just want power, I think you should buy a qs mid mount motor and get it over with.

What the lightest really brings for me is the promise of good torque sensing in a high quality drive that could be reliable.
Still hoping it will end up like that one day

IMO, this whole "lightest" concept is a little silly. I was a hard core road biker for many years and while never a total weight weenie I agree that a pound or 2 on a 18 pound bike that is to be human powered is a big deal. But 2 pounds difference on an e-bike that will weigh in at ~40-50 pounds (with battery) and be powered by ~1000w of motor power is trivial. IMO the $ and engineering required to trim a couple pounds off the motor could be better spent improving other aspects of the design.... or just allowing it to be sold for less $.

Vbruun said:

Great points. Buying the lightest ever motor to pair it with a heavy hub is kind of backwards.

But honestly, I only think the lightness of this drive is relevant in eMTB applications.
Otherwise, the massive battery needed for range at speed will outweigh the ligness gains anyways.

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Estoy completamente de acuerdo, es un kit muy caro.y con muy poca potencia.

Vbruun said:

I somewhat agree.
If you just want power, I think you should buy a qs mid mount motor and get it over with.

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Not the case for me, i want just enough power and no more. A QS mid is large enough and heavy enough to severely compromise the bike in a number of ways.

raylo32 said:

IMO, this whole "lightest" concept is a little silly. I was a hard core road biker for many years and while never a total weight weenie I agree that a pound or 2 on a 18 pound bike that is to be human powered is a big deal. But 2 pounds difference on an e-bike that will weigh in at ~40-50 pounds (with battery) and be powered by ~1000w of motor power is trivial. IMO the $ and engineering required to trim a couple pounds off the motor could be better spent improving other aspects of the design.... or just allowing it to be sold for less $.

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The 25% less good version of this would be the Revel Propulsion drive, which achieves having a reasonable Q factor and not needing a proprietary bike-side drivetrain. 5.8lbs and 650w rated. $1,290.

The 40% less good version of this mid drive is the CYC Photon and it currently costs $30 more and has less power, a significantly compromised Q factor, and driveline parts limitation like most asian mid drives. it's an above average, but not good design.

Considering this is a top shelf product not made with cheap asian labor and mid-low grade materials, i think it's a great value even if they were asking the full retail price of $1200.

Anyway it seems the shelf closest to the top shelf is more expensive than this, so can we really complain about the value..

raylo32 said:

IMO, this whole "lightest" concept is a little silly. I was a hard core road biker for many years and while never a total weight weenie I agree that a pound or 2 on a 18 pound bike that is to be human powered is a big deal. But 2 pounds difference on an e-bike that will weigh in at ~40-50 pounds (with battery) and be powered by ~1000w of motor power is trivial. IMO the $ and engineering required to trim a couple pounds off the motor could be better spent improving other aspects of the design.... or just allowing it to be sold for less $.

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I don't think its silly at all and I am glad they put in the effort to keep the weight down. When I see a product that is crudely designed or non-optimized in the physical package it always makes me wonder what other corners were cut.
Also, I worked hard in my fatbike build that the motor will be going on to keep weight low, and would hate to put an anchor on it.
Vbruun said:

Great points. Buying the lightest ever motor to pair it with a heavy hub is kind of backwards.

But honestly, I only think the lightness of this drive is relevant in eMTB applications.
Otherwise, the massive battery needed for range at speed will outweigh the ligness gains anyways.

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I would argue that the lightness of the drive is important in any type of bike other than maybe cargo. Anytime you jump a curb or lift the bike for transport you feel the weight. The light motor ALLOWs you to spend the weight somewhere else i.e. the igh

Vbruun said:

I somewhat agree.
If you just want power, I think you should buy a qs mid mount motor and get it over with.

What the lightest really brings for me is the promise of good torque sensing in a high quality drive that could be reliable.
Still hoping it will end up like that one day

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The lowest power QS mid drive (3Kw) weighs more than an entire XC mountain bike! Those are motorcycle class motors. I don't even understand how they can appear in the same conversation as a Bikee Lightest kit. It's not even the same universe.

I also think that the low weight will be great.
I am going to add about 4kgs(8,8 pounds) to my bike, with the motor and the battery combined.
I'm building 2 52v 520wh batteries, so I can bring a spare on long trips.
The total weight of my full suspension 29er will be under 20 kgs. That's great for a 1000w ebike.
My old setup was 4,5 kg motor and 5 kg battery, 750wh.(20,9 pounds)
I think it will feel more like a mtb again now with almost the same power.

rhauff said:

I don't think its silly at all and I am glad they put in the effort to keep the weight down. When I see a product that is crudely designed or non-optimized in the physical package it always makes me wonder what other corners were cut.

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It's a peculiar obsession of cyclists from places where bikes are not serious transportation. Outside of bicycles, only aerospace and racing are similarly obsessed with weight shaving (but for observably valid reasons).

From mopeds on up, everybody else making vehicles clearly values things like durability, cost, ease of use, and comfort more highly than weight. And places where bikes are regular transportation feel the same way about bikes. A Dutch pedal-only bike can weigh 25kg or more, but it gets used much more than an American recreational plaything.

I argue that corners are more likely to have been cut on a lightweight toy bike, either because of overzealous weight reduction, meaningless pursuit of novelty and marketing distinction, or plain old profit driven greed. Practical bikes have stronger customs and standards to uphold, and aren't the business of get-rich-quick types.

I've had heavy bikes and relatively light bikes. The light ones are easier to pick up. The heavy ones usually work better on the road. I don't mind a lightweight bike, but I'll take a strong one over a just-strong-enough one any time I have the choice.

neptronix said:

Not the case for me, i want just enough power and no more. A QS mid is large enough and heavy enough to severely compromise the bike in a number of ways.



The 25% less good version of this would be the Revel Propulsion drive, which achieves having a reasonable Q factor and not needing a proprietary bike-side drivetrain. 5.8lbs and 650w rated. $1,290.

The 40% less good version of this mid drive is the CYC Photon and it currently costs $30 more and has less power, a significantly compromised Q factor, and driveline parts limitation like most asian mid drives. it's an above average, but not good design.

Considering this is a top shelf product not made with cheap asian labor and mid-low grade materials, i think it's a great value even if they were asking the full retail price of $1200.

Anyway it seems the shelf closest to the top shelf is more expensive than this, so can we really complain about the value..

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I don't get how the Revel drive is 25% less good. The designer just isn't interested in higher voltage and power. The design of the system itself is quite elegant.

I would say Revel is equal, and Photon is 25% lesser. You are being overly harsh on both those systems.

nervagon said:

I don't get how the Revel drive is 25% less good. The designer just isn't interested in higher voltage and power. The design of the system itself is quite elegant.

I would say Revel is equal, and Photon is 25% lesser. You are being overly harsh on both those systems.

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Why revel is 25% less good:
- Motor weight x watts suggests lower efficiency.
- Requires a 36v battery.
- Owner of the company has a very anti DIY and anti high power attitude. <-- dealbreaker
- More expensive.

Why photon is 40% less good
- Q factor is so bad it's biologically unsound, even with a 68mm bottom bracket <--dealbreaker
- You're stuck with the proprietary drivetrain.
- Power/weight/efficiency wise it's only marginally better than a BBSxx ~10 years after the BBSxx was released. <-- dealbreaker
- Expensive relative to the overall quality of the drive.

YMMV, my opinion is very subjective and Q factor is where the Photon loses the most points in my eyes and i favor efficiency a lot because it correlates with hot roddability..

neptronix said:

Why revel is 25% less good:
- Motor weight x watts indicates lower efficiency.
- Requires a 36v battery.
- Owner of the company has a very anti DIY and anti high power attitude. <-- dealbreaker
- More expensive.

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650w opens up igh options, no?

maiz said:

650w opens up igh options, no?

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Yeah but you won't really need one at the lower speeds it can operate. You might as well stick to a derailleur setup which is more efficient.

So, while I was playing around on the GRIN motor simulator with the BBSHD and different voltages I realized that the difference between a 48V and 52V pack in RPM/top speed is only 2.5%.

And, aha, it dawned on my idiot brain. My loaded and unloaded RPM tests weren't done with a fully charged battery. That is the explanation for the lack of performance increase at 52V in my calculations. A somewhat depleted 52V volt battery performs about on par with a full 48V pack. The performance margin is razor thin already. Mystery solved: I'm just kind of dumb.

I should have a new next generation em3ev 19.5ah battery in ~6 business days.

I've got a laser tachometer, CA standalone, and a thermal camera. Should be able to get some data.
Maybe we can save this thread after all, IDK!

What is a "next generation" battery? Does it use anti-matter, dilithium crystals or have a warp core? . I have a couple of ~ 11 or 12Ah 52V EM3EV batteries that have served very well. 19Ah would be even better, assuming it isn't super heavy, because I am just using 2 water bottle mount screws to hold it on. A much heavier battery might need one of those double or triple Bobs.

neptronix said:

I should have a new next generation em3ev 19.5ah battery in 6 business days.

I've got a laser tachometer, CA standalone, and a thermal camera. Should be able to get some data.
Maybe we can save this thread after all, IDK!

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raylo32 said:

What is a "next generation" battery? Does it use anti-matter, dilithium crystals or have a warp core? .

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It's nothing super pivotal, but em3ev switched to 21700 cells, added potting, and UL rated their batteries.

I don't see any discussion of this on their website. Which form factor case and cells did you get?

neptronix said:

It's nothing super pivotal, but em3ev switched to 21700 cells, added potting, and UL rated their batteries.

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