29mm to 35mm to 50mm -> My evolution to the Cromotor

Ignoring my long bout with the 5305 hub motor (groan... I could just forget all of that) I have spent the majority of my time playing with "9C type" motors.

Remember when I landed those 8x8 turns? Those were fun... but 29mm is so little iron
Then we started landing those sweet 35mm HS3540's with sensors. I thought those were great and only just last night finally smoked one.

24S 70A limit
Ebikes.ca 12fet 40A controller modded with nothing but solder on the shunt
(that is how awesome those controllers are out of the box - 100V 70A - thanks Justin!)




So yea... when the cover reads 84C and you go in to eat dinner... then you come out 30 minutes later and it reads 89C.... well that is it. It stinks, its loud, and I done broke it. Time to move on. No looking back.

So some time back (when I decided to throw my life down the toilet ) I retired the KMX trike that had treated me so well. At the time I used to fuss over the fact that it could only take a 20" or 24" wheel but now... oh sweet Jesus... now that is just what I need. A machine that yearns for a 20" wheel filled with this sweet meat



Ok... ok... I totally get it that it makes WAY more sense to run a smaller, lighter, faster spinning in-runner with some gearing. Believe me... I totally get it. My first EV was a Steve Neu motor with a planetary gearbox and 14" prop pulling me on a skateboard. RC motors ROCK!

But I am a mechanical retard. My friends (for the most part) are mechanical retards too and retards who like to have fun gravitate toward that which will give them the most pleasure for the least pain. This is it. Right here. Sprung weight? yea... Single gear? Yea... but looky looky!!!

You see that gaper?
omfg... and those are already huge wires coming out. This is the shit right here - no doubt.



Now it is a little rough around the edges.. this aint for Mr. Fussy Pants who wants everything to look pretty. The men who made these motors had raw performance in mind and so a little finish work is to be expected. A second set of holes was drilled for bicycle spokes (which I like - I will be using 14G standard bicycle spokes that I measure, cut, and thread myself). The holes are not the best... some of them are not all the way through and some are dished (to accept the spoke head) while others are not. All that is fine though - I am just stoked that someone got the work started for me. If I wanted pretty I would just look at all the pictures I have of Luke's mom.

Isn't this always my story though? Am I not the phool who always jumps in on the first or second round of motors before all the bugs are worked out?
I wouldn't have it any other way

View attachment 2

Thick
Just thick... that is how I like them



And would you just look at that? OMFG can anyone say huge axle?
Kenny should take a few notes here.... My guess is that this one wont just strip off the first time I put a 10' breaker bar on it :lol:



So yea - that is all I have for now.
My super-trike is in the Santa Cruz mountains. I plan to collect it in the next few days. In the mean time I need to measure and cut up some spokes. I need to find a nice wide 20" rim. I need a really good hard tire (because I want to do smokey smokeshow burnouts to impress the cops). I need to velcro my pack down and I should be ready to go

Oh yea.... I hardly even have a controller... so I guess I will continue to use my modded out ebikes.ca 12 fet. I am going to see what that thing is made of. When it finally dies I will throw it on the pile of electronics we call Matthews desk and he can get his practice troubleshooting fets

This batch is for friends and family.
One for me, one for Matthew, one for my Mystery Machinist, and two for my esteemed love brother in the UK. I dont know what he will do with his - but I hope it involves a skinny guy popping a wheelie and busting his face up Seriously though - if you are in the UK and looking for one I would think about checking Jozztek in the near future.

As for me - After I get done testing these I think I will carry nothing but these motors for a while and see how things go. I think they will be the perfect complement to my new run of 18 fet controllers (that will never come to be...).

-methods

Very nice.. them axles will require deep slots to work right.. + torque arms..

Yesterday, i finally had a taste of FUN with my kmx, on 18S 60 amps, ( waiting on the next shipment of packs to run full 100v.. )

But i'm running an old X5.. :lol: ... itching to get one of thexe cro motors but got too many projects on the go ..... will wait for you guys to iron all the bugs out and get into it next season.. by wich time the next thing to have will be " new with bugs " .. argh.. never ends.

I am glad you are giving this motor the attention it deserves. Nobody has seriously talked about it just yet. I think it is seriously under-appreciated so far.

A few people have said that this forum has a Crystalyte bias. Once people get these motors going, i think that will change in short order ... hey... 10 pounds lighter, 5mm-10mm more magnet, and a proper axle. This is the end-game bicycle hub motor IMHO.

Good luck getting it above ambient temp with your 12fet :lol:

methods said:

I need to find a nice wide 20" rim.

Click to expand...

IMHO, the Recumpense 47mm wide 20" rims are pretty awesome and probably up to the job.

Hi Methods, I'm in the same mind. I have been going through the same dilema caused by force feeding too many phase amps into too little amount of copper in the smaller hubs. I orderd a Cro Then ordered another.
The smaller hubs are efficient putting out 1000-2000w as they where designed for, above this things start heating up, a lot, somtimes to much.
I consider most of thre mao hubs to be of equally auspicious quality so to compare 2 hubs i just multiplyed the magnet surface area of each by the radius of the stator=(potential torque) then divide by the tyre radius=(potential thrust). I get the Cro in a 24" rim about 30% better than a Magic pie in a 14" moto rim. Not as much as i thought but an improvment. The small stator diameter and large wheel in my example makes the cro suffer. But it will hopfully handle the square edge bumps better and not tear off the derailer so often.
With a run up my standard downhill bike could ride up a flight of 10 stairs before the conversion and with the 14" heavy hub i can't even hit a curb at full speed. I run a 26" front and a 14" rear motocross rim and what really rubs gravel in my wounds is when riding with my motocross mates and they call it a penny fathing!
I totally agree about the very large rc motor multi speed gearbox bikes. Toolman2's rc bike hoses both our pies on the same input for 60% of the power consumed on a typical off road ride. But it sounds like a VERY VERY big RC car is about to run over you.

Zappy

Another wise decision from MethTek.com

Keep me in mind when you get the next batch. I should be ready by then.

So I am trying to think of the absolute fastest and most hasty way to get this motor on the back of my bicycle....

A quick measurement shows that these are about the same spoke pattern as a 9C (though wider) so I think my plan is to tear apart a 2-cross that I built way back in the day (actually it was the first wheel I ever built). They are 14G stainless spokes that I turned myself... so they are a little hard to deal with... and that 2-Cross puts a bit of stress on the nipples... but I think this may be just what the doctor ordered for a quick fix.

1-Cross does not seem like enough for this much torque in a 26" wheel

The spokes were cut a touch long so the wider hub should not be a problem. As it stands the spokes almost get to the flats of the nipples, and I have a big bag of extra long nipples if things get desperate.



The only real problem with this quick fix is that the rim is so damn skinny... it is a high quality welded double wall rim - but it is for little nerds. I need something more substantial for my ego.



Yes... I see the angle that the spokes are coming out of those nipples and I know that is not a good thing.
Haste makes waste
Waste makes for good internet threads

Alternately I could just take apart a 20" 9C motor... I have one that I laced with good spokes around here somewhere - but I think it is at my hooch in the mountains.

The reality is when you own a shop full of ebike parts and insanely expensive stuff none of it ends up on your own bike... the crap is what ends up on your bike I would have it no other way though... I love it ghetto.

-methods

Ok... patience got the best of me for sure this time. I guess I am learning that if I don't do projects like this RIGHT NOW they just dont get done. It is kind of lame that I have a pile of beautiful Zero motorcycle rims at my other shop - but hey... this is what I have and I am about to be a guy riding a bike with a Cromotor in 20" on 24S so... yea.... it ain't that bad!

So I got so far as actually putting the 26" rim up on my work bench



Then I got to thinking about how much sweeter it would be to feel the fury of 20" under my butt....


So I gutted that sorry little 2812 motor and took its bones


Cheap Chinese pot metal crap is what this is...


All the spokes are in but not yet snugged up
View attachment 1

Going to go eat lunch now - when I get back I will tighten this up and go try to break my face. I wont have pedals (since I dont have a freewheel) so I will just take those bastards off and ride around like a mad hyena - 26" up front and 20" in the back.


-methods

24S in a 20" bmx wheel... Please video your face so I can see your expression on the first ride. After you twist the throttle I think you'll understand.

FWIW I can go 60mph on 30S so expect to run over 45mph, be careful it will be a little torquey.

Yea - I simulated it.
This is really for my trike where the instantaneous thrust is not so much of an issue... but today I have only my Kona Stinky Primo so that is what I will ride it on.

Compounding the problem my controller is a return from a customer. It saw 9V on the logic rail so now the throttle pretty much just works like a light switch... nothing... nothing.... BAM. lol...

This should be good. I have my summer riding jacket (it is 90F outside today) but I may just put on the real jacket and gloves.

-methods

Go steady there Methods! great post too, they sure do look pretty amazing and the vids I have seen from other folks are a little scary and a bit too fast for me :lol: however one would be fun in my KMX where I feel more planted and it will have less tendency to wheelie. I am going to get down and see Steve this summer so I can maybe try one out, keeping my eyes on this thread to see what you get up to!! stay safe and have fun

Grrr... kicking myself in the ass for using that Chinese rim and spokes
Things that should stretch dont
Things that should not stretch do
Grrr... every nipple stripped, every hole bulging, :?

Got it all laced up and pretty true tho
Off to the bike store to get tape and a tire before they close.

Got it wired up to my 100V 70A controller
Spins true in the stand - almost smashed my computer

Gonna smash my face tonight....

-methods

Ok - back from the bike store.

Decided to try a new tire - $20 bucks - I will let you know how it turns out
It fit on the rim very nice. Not too loose, not too tight.





I love these sick thick tubes! If you are running a standard tube stop it... just stop it :wink:
I did not fill this with goop - but I might - dont tempt me....

View attachment 3

Now this is an important point:
You see these two things? One is a rim strip and one is rim tape. Until now I always preferred the rim strip since it is so easy to put on and it can be reused. It never occurred to me though that with a double wall rim and high pressure on the tube.... it will tend to push down in the holes and beg to get cut. SO... from now on I am only going to run this cloth tape. Apparently it wont give so no concerns about tube titties getting nipped off in the hole.



Do yourself a favor and cut the hole bigger!!!
They tend to size these for some imaginary valve that is bigger than a presta and smaller than a schrader. It is WAY easier to cut a hole right now than it is to jam a phat schrader through once the tire is on the rim. Dont forget your downhill tube will have a MUCH THICKER SCHRADER valve... so make room.

And test fit it :wink:
Some times you have to take a little aluminum off of the rim.

View attachment 1

Ok - rim true, tire on rim, now where is my bike?



-methods

Did I mention how pissed I am at myself for using those damn Chinese pot metal spokes?
omfg...
at least 10 of the nipples are stripped round
Rim is bulging at a third of the nipples
Entire rim is out of true right where it joins (not welded)
Spokes wont stretch since they are so damn big

Take it from me (the guy who does it wrong every way possible on the path to doing it right....) Standard off the shelf 14G high quality stainless steel spokes will do the job every time. They stretch - so you can put a good tension on them and they keep it. You do it right and they are not going to break. You can get a spoke cutter for next to nothing.

Justin at ebikes.ca sells some nice 13G spokes cut to order. You can use his spoke length calculator to figure out what you need - it has hub motors loaded up already which makes the calculations a lot easier. Price is right too!

Or just send your hub to JRH
I was looking at his site the other day - some real pretty wheels on there. He has all the right gear to lace just about anything you want. If I was not the brokest bastard on the planet I might actually consider sending him one of these to lace up.

ok.. ok... back on track
Found my bike

The original Kona Stinky Primo that was once the basis for "Project Mayhem" (I would post a link but the pictures are hosed so no point)


So I spun the drops on this many X5's ago. Back when I was a dumb nut who thought I didn't need a torque arm.... flipping retard...

If you are not running a torque arm just stop it.
Seriously
Stop it!

Doc has some torque arms for sale that look like they were machined from a block of aluminum the size of a space shuttle. Justin has some nice beefy torque arms. Steer away from the Chinese Knock-offs that are selling for $5 all over the place. They literally don't work.

Anyhow - looks like I need to file down a few mm here. Plenty of room... plenty of room. I have a pair of custom "axle holders" that are not pictured here. All we really have to do is get this frame aluminum out of the way. The "axle holders" slide over the axle and bolt into place. I will have to enlarge those as well.



And the other side will need to go down a few mm too...
I hate this sort of work.



Forgot the Father in Law was coming for dinner so I am not going to be able to finish tonight. I have a couple of orders to pack, I have to run some people over with my car, maybe break a few beer bottles over some citizens heads. Be back tomorrow.

-methods

Doc's parts are solid steel.. not aluminum ! ( i got a pair.. going on m KMX tomorrow.. was going to use on chopper.. but kmx is priority right now )

When possible, i prefer to grind down the axle instead of the dropouts.. but they need to drop way in there so the nuts have a good clamp surface to keep things in place..... considering how much power this sucker is going to see.. i'd keep the axle material lol....

What we really need is a proper pinch type torque arm, not just relying on the flats.. but actually slotted with a nut and bolt at the end to grip the axle.. then add the nuts just for show.

The cromotor is certainly the best hubmotor made right now. I have been wanting one for myself but don't have the budget or the bike for it. Whats worse is that I have laced up 4 of them and have 2 more waiting for parts, so I get to fondle them but not use them :lol:


You are really going to have fun with em, can't wait to hear your experience in the saddle!

johnrobholmes said:

The cromotor is certainly the best hubmotor made right now. I have been wanting one for myself but don't have the budget or the bike for it. Whats worse is that I have laced up 4 of them and have 2 more waiting for parts, so I get to fondle them but not use them :lol:

Click to expand...

Gotta say, i actually feel bad for ya here :lol:

Looking good, Patrick!

Here's mine, getting close:



Those are 12 gauge spokes with custom made washers in the stock holes in the Cromotor. This Cromotor is from the last batch.

Ypedal said:

Doc's parts are solid steel.. not aluminum !

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doh - I don't know why I would say aluminum. That makes no sense.

johnrobholmes said:

Whats worse is that I have laced up 4 of them and have 2 more waiting for parts, so I get to fondle them but not use them :lol:

Click to expand...

:lol:

Methods,

1.
Your bicycle dropouts are giving you a message... use body armor while testing!

2.
10 bucks that you ll never look back after playing with Hal´s hub motor.

gensem said:

Methods,

1.
Your bicycle dropouts are giving you a message... use body armor while testing!

That is no joke friend... I have body armor and I dont even own a motorcycle! When I flew over the bars on my chopper bike I got hardly a scratch - only spot that hurt was my thigh where it got caught in the handlebars.

I know those drops look bad - but they actually dont hold the motor. There are steel plates that bolt on either side that completely surround the axle and hold it vertically and horizontally. Axle nuts are not even needed.

2.
10 bucks that you ll never look back after playing with Hal´s hub motor.

Click to expand...

I have been on a long voyage for many years trying to find a motor that is all smiles and no frowns. I am 99% sure this one will be the ticket... and if it is not... I will just have to drill 1" holes in it spray.

I think it is going to be great - especially in 20" with 24S.

I have a feeling that you will outgrow 24S rather quickly in that 20" wheel if high speeds are your bag.

I also have a feeling that someone is eventually going to need a 36FET with some of these to really max it out

https://ec.irf.com/v6/en/US/adirect/ir?cmd=catProductDetailFrame&productID=IRFB4127PBF

methods said:

I have been on a long voyage for many years trying to find a motor that is all smiles and no frowns. I am 99% sure this one will be the ticket... and if it is not... I will just have to drill 1" holes in it spray.

I think it is going to be great - especially in 20" with 24S.

Click to expand...

Im using 17" moped rims so you should get a bit more torque, but thats really not necessary the motor has alot of torque... I really wanted to have a higher kv cromotor, like 15kv with a bigger flux area and maybe even more cooper fill.

Speed is actually not my thing... too scared of losing my skin
(I say that speaking literally)

Acceleration is my thing... so I don't think it will be long until I need a higher current limit. Should have never sold Doc by 220A kelly controller.

Speaking of controllers... where the hell do I buy one?
Fark... I need a controller like right now. I am tired of waiting for myself to produce them.
Someone please sell me a controller 18 fet, 24 fet, 36 fet... I dont really care... any of them will do.
I need a fix to hold me off until I can get a line going. All of my manufacturers are dragging their feet.

Those fets are nice but that 20mOhm rdson is a bit of a buzz kill for me. Even the 4115 puts me off - I have tried to incorporate it into a few of my designs and I always end up back with the IRFB4110 and sub 1mOhm rdson.

-methods

neptronix said:

I have a feeling that you will outgrow 24S rather quickly in that 20" wheel if high speeds are your bag.

I also have a feeling that someone is eventually going to need a 36FET with some of these to really max it out

https://ec.irf.com/v6/en/US/adirect/ir?cmd=catProductDetailFrame&productID=IRFB4127PBF

Click to expand...