'lightest.bike' 1.7kg 1000w mid drive

[neptronix]

I would bet their measurements were done with the dual cog version. 'at the chainring' would make sense there.

 

[neptronix]

But then those claims are no longer valid?!?

I think you'd have to ask them for clarification but we're probably talking about a ~5nm possible difference between dual chainring and the sort of single chainring configuration we have today.

 

[neptronix]

Honestly we can only speculate. RPM and other data is never supplied with these newton meters ratings.

I've seen 250w drives advertise 120nm also.

continuous wattage is the better determinant of what the power will be.

 

[1boris]

The bafang G310 is supposedly whisper silent due to the spiral cut gears. But that hub drive is easy to blow up.

The q128H 800w is pretty good motor

AKM-128H 36V/48V 800W Rear Driving Hub Motor For ebike [AKM-128H 36V800W] - $125.00 : Zen Cart!, The Art of E-commerce

Zen Cart! AKM-128H 36V/48V 800W Rear Driving Hub Motor For ebike [AKM-128H 36V800W] - ★★★★★ AKM-128H 36V/48V 800W Rear Driving Hub Motor For ebike Specification: 1. Voltage: 36V/48V. 2. Brake type: V-brake, rim brake and disc brake are compatible 3. Connector: Waterproof Hall sensor and...

topbikekit.com

 

[neptronix]

You have lots of millimeters of adjustment and things you could flip to make dual chainring + throttle happen.
Doesn't seem like a big science experiment.

Rear gearing cassette swap could also possibly change the ratio favorably? or have you already got a 11t on the wheel?

Can the top of the sprocket really not contact the top of the chain? it may reduce chain wrap to the drive's sprocket but the torque sensor adds some wrap back.. so.. if we can do that, there's no reason you couldn't put a 46t on there.

 

[neptronix]

Medium mounts are here!
Very happy, it looks like it could make the motor fit with my recumbents, though it will look goofy when installed!

 

[Swifty]

Lightest ebike kit Product Configurator

Lightest ebike kit. Save 25% with presales. You can select accessories and upgrades in the checkout section. Included Items: Lightest motor, Ergal (Aluminum Alloy 7075 ) crankarms, External premium freewheem, Magnesium Chainring Spider, Aluminum chainguide, 36T Chainring, LCD e-bike display

www.lightest.bike

 

[neptronix]

That sounds about right for mid drives and how they're rated.
Take a 100nm rated ( at the crank ) with a 30T gear to a 10T gear..
What do you get at the wheel.. 33.33nm

Consider that 23nm of torque at the wheel is produced by a hub motor at 35mph.
33nm when in a 11t gear on the cassette would be pretty awesome if true, but this 33nm is probably a peak value, or at low RPM.

Once you are pedaling it is probably putting out more like 20nm since this motor is tuned for 1000w continuous.
( notice that on this graph, the torque is reduced the fast we go.. just a natural motor power curve.. a mid drive will also have this curve across the pedal speed range. )

Here's a leafbike 1.5kw model, used as a model for a very efficient motor ( lightest should be more efficient than this, but this is one of the more efficient hubmotors. )

 

[raylo32]

All these numbers... all these graphs... all these maths... Will this motor actually drive a bike? Do you guys have one on the road (or trail) yet?? And why does the chart above in post 507 say "offroad: no"?

 

[raylo32]

Sounds like a lot of bother for an unproven motor, especially hacking your BB shell. I hope it is worth it.

I’m not in a position to test mine. I’ll be chopping and facing my 73mm bottom bracket down to 68mm, waiting for a new crankset and chainring to arrive, and bleeding my brakes before I’ll have a functional bike.

I was able to find a new in box HXR Easy Shift crankset on eBay for a good price. That will give me what Bikee can’t. Outboard bearings and a 30mm axle two piece crankset. A modern bottom bracket. But I will need to chop down my BB shell to 68mm to make that work. I’ve covered this already, but the motor mounts turn a 73mm BB into a 79mm BB which will cause problems when trying to fit any other bottom bracket than the cheap square taper adjustable one from Bikee. So I have some work to do.

 

[Pilot Engineer]

I've decided against building up my new(old) bike with the Bikee Lightest. I'll either just ride it as an acoustic bike, or get the CYC Photon.

I was able to find a new in box HXR Easy Shift crankset on eBay for a good price. That will give me what Bikee can’t. Outboard bearings and a 30mm axle two piece crankset. A modern bottom bracket.

How would you fit a modern bottom bracket with 30mm axle two piece crankset on the Photon?

 

[Pilot Engineer]

View attachment 346242

I swapped my medium mounts with @neptronix for his short mounts. Posting this photo to illustrate the incompatibility between the short mounts and a 42T chainring. There’s no clearance. Also, the motor cog is narrow-wide, and so a narrow-wide chainring is probably not an option. Getting the motor cog and chaining to line up with the right amount of slack if both were narrow-wide would be sheer luck.

Ah, you got me!

Well, I guess a more efficient approach would be to put a 38T on the bike above and you'll be riding your bike, with 10 minutes of work. From 42T to 38T means a 9.5% increase in cadence comparing to your target one: I guess that's not a huge deal.

But if you want to put a photon on, you go ahead with that.

BTW, for other members, I'd like to point out few things, in random order:
1) there's no reason why a narrow-wide chainring wouldn't match the motor
2) the motor wasn't specifically designed for the 36T chainring: it works with any chainring size. The higher the cog, the higher is the perceived torque at the chainring. The torque at the wheel will be the same, but if you had a motor exerting the torque at the chainring, by increasing the chainring size, you'd be decreasing the torque at the wheel.
3) the motor is compatible with 68, 73, 83, 92, 100 and 120mm bottom brackets
4) The motor can come with either square taper or ISIS spline. But we don't know the parents of the ISIS spline version.
5) The larger chainring you can use with short mounts is 36T. You can find this and other info in the Compatibility section of our website ( https://lightest.bike/COMPATIBILITY )
6) If you want additional info about the motor: simply ask me or write to info@lightest.bike !

Enjoy your rides!
All the best
Matteo

 

[Pilot Engineer]

I'm sorry, I just have to add some additional commentary. This whole time, the engineer of the Lightest Kit, and founder of Bikee has been lurking on this thread... and finally this is his contribution to the discussion. He could have answered questions about the confusing torque rating, addressed manufacturing errors in the mounting brackets, offered words of encouragement or insight.

Nope. He drops in with this little elon-style shitpost.

I introduced myself in the 9th post of this thread, and I answered to those who asked questions to me. You've been sending us questions by email, to which we all replied.

So if you're asking questions here, my guess is that you don't want to hear our answers, otherwise you would have sent us an email rather than posting here and hoping for me to answer.

Unfortunately I cannot always keep up with the different threads on different platforms, that's why I pointed out that if someone has a question for us, the best way is to contact us!

 

[neptronix]

@Pilot Engineer - While you're here:
Is there any problem with installing a chainring a little larger, making the chain touch the top and bottom of the chainring?

I notice in most installation pictures, the top part of the chain never touches the chainring.

 

[Pilot Engineer]

"Well, I guess a more efficient approach would be to put a 38T on the bike above and you'll be riding your bike, with 10 minutes of work. From 42T to 38T means a 9.5% increase in cadence comparing to your target one: I guess that's not a huge deal."

"The larger chainring you can use with short mounts is 36T."

Those two statements aren't compatible.

"The higher the cog, the higher is the perceived torque at the chainring. The torque at the wheel will be the same..."

OK "perceived torque." I'm not familiar with that measurement. I'll need to check around with other vendors to get the perceived torque ratings of their motors.

The first statement ( put a 38T on the bike above) is referred specifically to your bike, my insight .

The second statement ( "the larger chainring you can use is 36T) is the general rule, without seeing the bike. If a bike has a more open angle, then the 38T won't fit.

About the perceived torque, think about it in this way:

You have a photon, with 110Nm at the chainring. You put a 36T chainring on it, with the smallest cog at the wheel being 12T ( for simplicity sake). The torque at the wheel will be 110*12/36= 36Nm.

Now, on the same bike, you switch to a 42T. Now your torque at the wheel will be 110*12/42=31Nm.

Now, on the same bike, you put a Lightest, high torque, with 120Nm. The torque at the motor sprocket is 33Nm. Since the motor sprocket has 10T, the torque at the wheel is 33*12/10=39,6Nm.

Now, on the same bike, with the Lightest, you put the 42T chainring. Now the torque at the wheel will be the same as before: 33*12/10=39,6Nm .

In order to exert this 39,6Nm torque at the wheel, with the 42T - 12T gear ratio, the photon should exert 39,6*42/12= 139Nm at the chainring.

So, to get the same performance, the photon should "add" 29Nm of torque ( 26% more!). This is not real torque that our motor added, it's just perceived, That's why I said that "the higher the cog, the higher is the perceived torque at the chainring.

 

[Pilot Engineer]

@Pilot Engineer - While you're here:
Is there any problem with installing a chainring a little larger, making the chain touch the top and bottom of the chainring?

I notice in most installation pictures, the top part of the chain never touches the chainring.

Hi Neptronix, the chain and the chainring are spinning in sync, so having it slightly touching the top of the chainring will only bring some rubbing noise in the small rear cog.

So, you should decide, basing on how much it touches, whether it's worth or not. If the chain slightly touches and you're almost never using the smallest cog because your mainly use the bike on mountains or hills, the you can go for it. If there's an consistent overlap ( the whole chain is overlapping the chainring ) and you're frequently using the smaller cog, then I'd go for either a longer mount or smaller chainring.

Hope this helps,
Matteo

 

[neptronix]

^-- makes sense to me that the motor cog is determining the output torque instead of the chainring.

 

[Pilot Engineer]

Your introduction, the 9th post of this thread was 4 years ago. FOUR YEARS. And your last contribution to this thread was a year and a half ago. You are only drawing attention to the fact that we payed you only to wait years for this motor kit to finally arrive.

Your replies to emails have been copy pasted already to this thread. Nobody was baiting you into answering. I am sharing my experience with the other members of this forum... a space dedicated to sharing experiences related to the electrification of bikes. As you've seen, we've even exchanged parts from your kit as well.

When I pointed out that your medium mount is countersunk on the wrong side, support asked me to fix it myself, and then offered me a short mount instead, which was backordered. That wasn't a solution. As I have a 42T chainring. If you can't tell, I gave up on Bikee support. Can you blame me? Step outside yourself, and try and view things objectively... can you you blame me for giving up on support?

Your posts seems full of resentment, and I'm sorry for that.

If all this is due to the fact that the support asked if you could countersunk yourself a plate which was out of stock, I really apologize. For some that's a quick fix. Moreover if you consider that you were planning to trim off your bottom bracket, the countersunk thing is way easier. We told you that the right plate was coming in 20 days and we offered to send you one free of charge.

 

[neptronix]

Can you please take this private, you've been ragging on this company for many months and chose to not even try the drive.
Kind of beating a dead horse then if you are not looking for solutions... not helpful for others looking at hte thread trying to find out of this drive is good or not.


Shame nobody else has got it running but we are out of biking season in most part of the world. ES gets a lot less active around this time.

Luckily, it's just starting to thaw over here. Today is the first day of bike-compatible weather, hitting 50f in about 1 hour from now.
Weather here usually stops sucking around mid February.
I should be back in action pretty shortly.

 

[nervagon]

Can you please take this private, you've been ragging on this company for many months and chose to not even try the drive.
Kind of beating a dead horse then if you are not looking for solutions... not helpful for others looking at hte thread trying to find out of this drive is good or not.


Shame nobody else has got it running but we are out of biking season in most part of the world. ES gets a lot less active around this time.

Luckily, it's just starting to thaw over here. Today is the first day of bike-compatible weather, hitting 50f in about 1 hour from now.
Weather here usually stops sucking around mid February.
I should be back in action pretty shortly.

OK. All of my posts have been removed from the thread, and I will never mention this motor again on ES.

 

[neptronix]

OK. All of my posts have been removed from the thread, and I will never mention this motor again on ES.

Aight, best wishes to you!

Hi Neptronix, the chain and the chainring are spinning in sync, so having it slightly touching the top of the chainring will only bring some rubbing noise in the small rear cog.

So, you should decide, basing on how much it touches, whether it's worth or not. If the chain slightly touches and you're almost never using the smallest cog because your mainly use the bike on mountains or hills, the you can go for it. If there's an consistent overlap ( the whole chain is overlapping the chainring ) and you're frequently using the smaller cog, then I'd go for either a longer mount or smaller chainring.

Hope this helps,
Matteo

Makes sense, thanks for the info!

I think the unfortunate thing about this drive is the chainring height limitation on most bikes.

At 90RPM cadence..

With 29" wheels, you need a 42T with a 10T rear cog to hit 32mph (51.5kph) which means we have more room in the gearing than needed ( good ).
With 26" wheels and the same 10T > 42T, we can only hit 28.9mph (46kph) in that gear. So we want a little taller chainring to hit the max continuous speed.

Nervagon noticed the original design was using 2 chainrings in some configurations. Can the drive still be used this way to overcome the chainring height problems when you need > 42T with some various adjustments? or are there some other problems with that?

 

[nervagon]

My build:
Progetto: Motore Piccolo Arrabbiato

As I complete my sunk cost fallacy project, I will honor my word, and never mention this company or product by name. And I promise to thrash the shit out of this motor!

 

[neptronix]

Bad news for CLWB recumbents. Chainline just doesn't work. Drive was not designed to be rotated by 180 degrees.



Dual chainring would be the way to go on a BikeE or similar CLWB.
The mid mount is not long enough to put the drive on.

What can i say, it was not designed to be installed backwards.

It looks like the inframe mount, hybrid mount, or long mount might make the dual chainring drive style possible because the drive appears to have sliding mounting points. I imagine there is enough adjustment to act as a tensioner.

Would the above idea possibly work, @Pilot Engineer?


Comments on installation.

Tons of bags of parts ( nuts, bolts, spacers, washers, everything else ) is a little intimidating. Maybe 60 parts all in all, and some redundant for my case ( better to have too much hardware than too little ).

Some things could have been preinstalled for an easier and less intimidating science project.

More spacers for things than you can shake a stick at, lightest co really wanted to make sure your chain line is good. I give this two thumbs up.

The idler arm gashes into the metal case when installed. Could be a lot more elegant.

68mm bottom bracket fitment was good and easy.
Driveline lined up with no drama. Nice.

Chainring carrier bolts and nuts seem undersized. The real problem is torquing down the tiny drive head. It looks like it can take a thicker bolt too for a better connection. I think this part of the hardware might be too lightweight.

Out came a 110mm BB and in went a 122mm BB.

I made a really big mistake when assembling it and put both bearings on one side of the 122mm axle. This lead to me trashing the threads one of the plastic cups. Totally my bad.

The mid size drive plates that hold together the assembly can be reversed and this makes the tapered nut > chainring interference problem mentioned by nervagon previously disappear.

The maxaraya recumbent has a middle bottom bracket where i could mount the drive forward as designed, but the solution might involve too much creativity. One fun possibility is that i could flip what side i want to drive, and use the front.




The issue with a 42T chainring being not big enough to hit top possible speed on a 26er is a big problem for me. I would want 48T. I also may want to run a 23" motorcycle tire for ultra puncture resistance. That creates another gearing issue. So on a 26er, i am probably looking at dual chainring. On the maxaraya above, some creativity may yield a solution without a longer mount and dual chainring, hence retaining the originally high efficiency skip-a-reduction-drive quality of this motor.

Pray for me, this is going to be the most difficult bike motor install of all time, and it's kind of my fault

 

[Pilot Engineer]

At 90RPM cadence..

With 29" wheels, you need a 42T with a 10T rear cog to hit 32mph (51.5kph) which means we have more room in the gearing than needed ( good ).
With 26" wheels and the same 10T > 42T, we can only hit 28.9mph (46kph) in that gear. So we want a little taller chainring to hit the max continuous speed.

Nervagon noticed the original design was using 2 chainrings in some configurations. Can the drive still be used this way to overcome the chainring height problems when you need > 42T with some various adjustments? or are there some other problems with that?

As long as the chain stays on top of the chainring, then you can use larger chainring.

The 2-chainring configuration is still valid, but you'll be able to only use that with the throttle as torque sensor won't work.

 

[Pilot Engineer]

Dual chainring would be the way to go on a BikeE or similar CLWB.
The mid mount is not long enough to put the drive on.

What can i say, it was not designed to be installed backwards.

It looks like the inframe mount, hybrid mount, or long mount might make the dual chainring drive style possible because the drive appears to have sliding mounting points. I imagine there is enough adjustment to act as a tensioner.

Would the above idea possibly work, @Pilot Engineer?

This is a really tough installation and a lot of creativity is needed. I would suggest to change the bike, but let's try to find a solution, knowing that it will be something very, very peculiar.

One question: what happens if you rotate the motor so that it will sit in front of the head tube of the first recumbent that you posted?

Would you please post a picture of the motor, with medium mount in that position?