plans to build a mid drive in ns snabb

[neskafe81]

What motor to make a project or replica of paradox kinetics or cyc x1 with what controller?
I have access to cnc machines and milling and lathes.

I am thinking about a project for my ns snabb bike.
I live in a country where cyc x1 costs a lot...
I am thinking about using a motor from a skateboard or rc car.
I wonder if such a motor would be ok?
6384 120KV 2970W 2.5 ~ 4N/m

 

[E-HP]

Are you saying that you’re trying to replicate a 250Nm system by starting with a 4Nm motor?

 

[neskafe81]

Are you saying that you’re trying to replicate a 250Nm system by starting with a 4Nm motor?

What motor do you suggest? As I've seen, most of all motors don't have any big torque, the old cyc x1 had about 2nm, most of them have high RPM 9 to 22k RPM, so it seems to me that some motor from a drone, skateboard or larger scale rc would make sense.

 

[amberwolf]

Are you saying that you’re trying to replicate a 250Nm system by starting with a 4Nm motor?

That can work, if you build a good gearbox, as long as you keep in mind the output will be only 1/63rd as fast as the motor itself.

Let's say you only want to go 10mph, for an easy number. From this chart

Wheel diameter to speed/RPM chart

When contemplating a non-hub motor, the maximum motor RPM target and gearing equations can get complex. By selecting the lowest top speed that can satisfy your performance needs, torque will be maximized across the resulting rpm band. From reading here, most builders have settled on wheel...

endless-sphere.com

that gives 129.3rpm needed at a 26" wheel.

If the motor is 120kV, then it spins 120 times for each volt applied to it.
To get the required torque you need to gear that down to 1/63 of that speed, so you get only 1.9rpm per volt out of that.

To get 129rpm for 10mph at the wheel (because you can't gear that up or you lose teh torque you're after), you have to use a battery that is at least 129 / 1.9 = 68v.

If you want 20mph, you need at least twice that.

Etc.

None of that considers the power levels required, since most of the tiny motors you're looking at need a lot of airflow to run at the rated power, so you either have to use a bigger motor or run it at less power or add a forced-air cooling system, or some kind of liquid cooling, etc.

 

[E-HP]

That can work, if you build a good gearbox, as long as you keep in mind the output will be only 1/63rd as fast as the motor itself.

Let's say you only want to go 10mph, for an easy number. From this chart

Wheel diameter to speed/RPM chart

When contemplating a non-hub motor, the maximum motor RPM target and gearing equations can get complex. By selecting the lowest top speed that can satisfy your performance needs, torque will be maximized across the resulting rpm band. From reading here, most builders have settled on wheel...

endless-sphere.com

that gives 129.3rpm needed at a 26" wheel.

If the motor is 120kV, then it spins 120 times for each volt applied to it.
To get the required torque you need to gear that down to 1/63 of that speed, so you get only 1.9rpm per volt out of that.

To get 129rpm for 10mph at the wheel (because you can't gear that up or you lose teh torque you're after), you have to use a battery that is at least 129 / 1.9 = 68v.

If you want 20mph, you need at least twice that.

Etc.

None of that considers the power levels required, since most of the tiny motors you're looking at need a lot of airflow to run at the rated power, so you either have to use a bigger motor or run it at less power or add a forced-air cooling system, or some kind of liquid cooling, etc.

That doesn't sound like a replica of a CYC X1.

 

[scianiac]

Many similar drives have been built but I would first define what you actually want, if you want everything the CYC has that is going to be much harder than doing something with more limited applications (but probably better at those). That is so say the CYC drive can do many things but many tradeoffs have been made for it to do those. If you want a lightweight drive, with high peak power, that can be pedaled, with torque sensing, driving through the bike's drivetrain directly that is a lot all at once. Which is why the CYC is prone to overheating, power ratings are peak not continuous, hard on dirvetrains, noisy, and complex.

My point is what are you after, it's fine if it's all of those things but it's often much easier and in the end better to design a build that is very good at what you are going to really use it and throw out all the features you don't really need. For instance the tradeoff I made on the bike in my avatar is it can't really be pedaled but what I gained was more power, more reliability, a much simpler and quieter gear reduction. On the other hand if you wanted more pedal assist performance you can use a smaller motor with less power so the gear reduction doesn't need to be as beefy and the bike's drive train can be used.

 

[neskafe81]

Bardziej myślę o zrobieniu czegoś takiego jak cyc x1 i paradox kinetics, ale muszę pomyśleć o przekładni i silniku. Planowałem zapłacić do 250, może 300 euro za sam silnik, mogę kupić przekładnię lub zrobić ją, jeśli będę trzymał się modelu paradox kinetics, nie będzie to trudne. Gorzej jest z przekładnią cyc x1, ponieważ jest tam przekładnia planetarna.

 

[neskafe81]

Zamierzam używać tego silnika w enduro i downhillu, dlatego chcę go zbudować, ponieważ każdy middrive do 700 euro jest słaby i mocno odstaje od ramy. Najbardziej zależy mi na tym, aby motocykl jeździł bardziej jak motocykl niż typowy motocykl, dlatego myślę o czymś takim jak wyżej wymienione projekty.

 

[amberwolf]

That doesn't sound like a replica of a CYC X1.

I'm sure it isn't--it was just a "let's say" to give some numbers examples for the OP (asusming I even did the math right).

FWIW, the CYC X1 has a reduction gearbox on the end of the motor, as well as the gear reduction from the motor output to the pedal chainring; I don't know what that total reduction is. but that's how any of these ssmall motor drives get the power they do.

 

[amberwolf]

Bardziej myślę o zrobieniu czegoś takiego jak cyc x1 i paradox kinetics, ale muszę pomyśleć o przekładni i silniku. Planowałem zapłacić do 250, może 300 euro za sam silnik, mogę kupić przekładnię lub zrobić ją, jeśli będę trzymał się modelu paradox kinetics, nie będzie to trudne. Gorzej jest z przekładnią cyc x1, ponieważ jest tam przekładnia planetarna.

Zamierzam używać tego silnika w enduro i downhillu, dlatego chcę go zbudować, ponieważ każdy middrive do 700 euro jest słaby i mocno odstaje od ramy. Najbardziej zależy mi na tym, aby motocykl jeździł bardziej jak motocykl niż typowy motocykl, dlatego myślę o czymś takim jak wyżej wymienione projekty.

I don't understand any of that.

 

[marty]

I don't understand any of that.

Polish to English

I'm more thinking about doing something like cyc x1 and paradox kinetics, but I need to think about the transmission and engine. I was planning to pay up to 250, maybe 300 euros for the motor itself, I can buy the gearbox or make one, if I stick to the paradox kinetics model it won't be difficult. It's worse with the cyc x1 gear because it has a planetary gear.

I plan to use this engine in enduro and downhill, that's why I want to build it, because every middrive up to 700 euros is weak and sticks out significantly from the frame. What I really want is for the bike to ride more like a motorcycle than a typical motorcycle, so I'm thinking about something like the above-mentioned designs.

 

[neskafe81]

sorry my translator is broken

 

[neskafe81]

I don't understand any of that.

I translated on my phone and at that moment I had the entire page translated into Polish and I didn't see that I had sent it in Polish, I understand English but I wanted it to be as good as possible and I decided to use a translator

 

[neskafe81]

here is a link to the topic that got me really interested in building such a drive, it looks easy, I already asked a colleague from work and he told me that building such gears shouldn't be a problem. I'm just wondering if there is an alternative to the scorpin engine? A cheaper one that doesn't cost 500 euros, and what kind of controller for something like that?

link

PARADOX KINETICS

This looks nice: http://factoryjackson.com/2015/03/18/paradox-kinetics-high-power-e-bike-motor/#.VQu-tEXtwkE.twitter https://www.facebook.com/paradoxkineticsems/ http://paradoxkinetics.com Anybody heard of it/tried it? I like the "no secondary chain" setup like bafang. Just wonder how...

endless-sphere.com

 

[2old]

A couple of members who don't seem to post anymore used RC motors. You might start by looking up their threads.

 

[lnanek]

I often see the smallest Bafang middrive sell for under 200 on AliExpress. If my budget was 250-300 for the motor I'd just immediately buy that instead of messing around with RC motors.

 

[E-HP]

I often see the smallest Bafang middrive sell for under 200 on AliExpress. If my budget was 250-300 for the motor I'd just immediately buy that instead of messing around with RC motors.

Plus you don’t need ear plugs while riding it.

 

[scianiac]

Based on that translation that narrows down the design goals a fair bit, you should look at how the Lightning Rods kits are designed, that type of reduction is pretty ideal for what you are looking for. That is if you are looking for a high power drive that you don't need to pedal, like an ultralight motorcycle. The key is you don't try and reduce the RPM at the crack to pedaling speed, you just reduce it some and then do the rest of the reduction using a very small front chainring and a very large rear. That means you don't need any gearbox and a simple single stage chain or belt drive from motor to chainring will work. You also want to use a quite large outrunner, the rated specs on those motors assume very good cooling and even then are more like peak.

But honestly if you are after that kind of power you might as well just buy an LR kit, like his motors are about the price you're talking about and are better suited than outrunners in many ways. The kit cost more but so will whatever you build yourself. I had planned to build a drive with a large outrunner and maybe I will out some point but honestly it would end up looking pretty similar to an LR kit as I have not seen any better design, certainly way better than the CYC.

 

[neskafe81]

Based on that translation that narrows down the design goals a fair bit, you should look at how the Lightning Rods kits are designed, that type of reduction is pretty ideal for what you are looking for. That is if you are looking for a high power drive that you don't need to pedal, like an ultralight motorcycle. The key is you don't try and reduce the RPM at the crack to pedaling speed, you just reduce it some and then do the rest of the reduction using a very small front chainring and a very large rear. That means you don't need any gearbox and a simple single stage chain or belt drive from motor to chainring will work. You also want to use a quite large outrunner, the rated specs on those motors assume very good cooling and even then are more like peak.

But honestly if you are after that kind of power you might as well just buy an LR kit, like his motors are about the price you're talking about and are better suited than outrunners in many ways. The kit cost more but so will whatever you build yourself. I had planned to build a drive with a large outrunner and maybe I will out some point but honestly it would end up looking pretty similar to an LR kit as I have not seen any better design, certainly way better than the CYC.

I'm still thinking about a healthy UAV engine
or agricultural engine such an engine generates a lot of power it is small and light about 1-3kg. Prices on AliExpress around 150 to 250 euros in FPV drones I know a lot and I have a friend who knows about it, this Lightning Rods set you wrote is cool but it has a really big engine and I want to build a universal set, and it will not fit well into the NS snabb 2019 frame because of the strongly extended lower tube in front of the crank support
thanks a lot for suggesting the idea of "Lightning Rods" I didn't see what it was called before. I'll think about it now.
and do you know any engines for it? So that it is not too big but strong enough?

 

[neskafe81]

ok I think I know what engines would be cool to consider I think they will be good
https://pl.aliexpress.com/item/1005004503876385.html -qs90

https://pl.aliexpress.com/item/1005...ł!644,39 zł!!!1132.70!1132.70!@2103892f173852 77058388865e69a6%2112000036083157230%21sh%21PL%212095346353%21X&spm=a2g0o.store_pc_al lItems_or_groupList.new_all_items_2007540475720.1005005390927198&gatewayAdapt=glo2pol ----

---motor 1500-2000W Voltage

48V -52V
Rated power
1500W
Maximum power
2000W
No-load speed
3000rpm
Maximum efficiency
≥90%
Maximum Torque 7.0Nm
Peak Torque 35N.m

Maximum current limit
80A
Phase current peak
150A
or so https://pl.aliexpress.com/item/1005005878654216.html?pdp_npi=4@dis!PLN!979,7 9%20z%C5%82%21979%2C79%20z%C5%82%21%21%211722.25%211722.25%21%402103892f173852734147 93701e69a6%2112000034679077325%21sh%21PL%212095346353%21X&spm=a2g0o.store_pc_allItems_or_groupList.new_all_items_2007540475720.1005005878654216&gatewayAdapt=glo2pol
Net Weight: 1.66KGS
KV: 270
Discharge Current 5.1A/10V
Motor Resistor: 0.0057ohm
Max Current 200A
Outer Diameter 83mm
Max Volt 50V
Max Continuous Power 10kW

 

[StillDre]

ok I think I know what engines would be cool to consider I think they will be good
https://pl.aliexpress.com/item/1005004503876385.html -qs90

https://pl.aliexpress.com/item/1005005390927198.html?pdp_npi=4@dis!PLN!644,39 zł!644,39 zł!!!1132.70!1132.70!@2103892f173852 77058388865e69a6%2112000036083157230%21sh%21PL%212095346353%21X&spm=a2g0o.store_pc_al lItems_or_groupList.new_all_items_2007540475720.1005005390927198&gatewayAdapt=glo2pol ----

---motor 1500-2000W Voltage

48V -52V
Rated power
1500W
Maximum power
2000W
No-load speed
3000rpm
Maximum efficiency
≥90%
Maximum Torque 7.0Nm
Peak Torque 35N.m

Maximum current limit
80A
Phase current peak
150A
or so https://pl.aliexpress.com/item/1005005878654216.html?pdp_npi=4@dis!PLN!979,7 9%20z%C5%82%21979%2C79%20z%C5%82%21%21%211722.25%211722.25%21%402103892f173852734147 93701e69a6%2112000034679077325%21sh%21PL%212095346353%21X&spm=a2g0o.store_pc_allItems_or_groupList.new_all_items_2007540475720.1005005878654216&gatewayAdapt=glo2pol
Net Weight: 1.66KGS
KV: 270
Discharge Current 5.1A/10V
Motor Resistor: 0.0057ohm
Max Current 200A
Outer Diameter 83mm
Max Volt 50V
Max Continuous Power 10kW

I was looking at the QS90 70H and the thing that makes me not want to use it, is the width. Either I'll have to completely forgo using my normal bike drive train or I'll need to position the motor so that the shaft runs along the length of the bike, and then use a 90 degree gearbox to turn the shaft so that the shaft runs along the width of the bike. I'm worried that's beyond my design abilities

 

[amberwolf]

use a 90 degree gearbox to turn the shaft so that the shaft runs along the width of the bike. I'm worried that's beyond my design abilities

There are OTS rightangle gearboxes of many types, shapes, input shafts / collars, sizes, and torque ratings, depending on your budget and system technical constraints, and available time to look them up.

Even places like Grainger have them in numerous designs (although theyll probably cost more there).

Theyre also available in old brushed powerchair motors, which will handle quite a bit of torque, though they are rather large and heavy. (I've used two different kinds on the old CrazyBike2, along with the attached brushed motor, with enough torque at just 36v to tear apart chains, sprockets, and rip the rear axle out of the dropout and bend up the wheel when the chain derailed).

The typical angle grinder will have one that can do a fair bit of speed, dunno the torque capability. Better grinders have better gears and bearings. (there've been a few bikes built to use a whole angle grinder as a middrive).

 

[lnanek]

Reminds me of this video where fully half the time is spent on getting that 90 degree gearbox extracted and building a frame for it to mount it to the bike:

 

[scianiac]

Or you could just like use a shorter motor.

 

[lnanek]

I've seen some RC motor hacks where they put the motor on the rear rack. Should be less concern about motor width if it is back there instead of between your legs/pedals.

Kind of tougher on a full suspension, though. Maybe you can attach the rack only to the swing arm/chain stays or something.