Belt and chain custom frame build thread

[Hummina Shadeeba]

Luckily there’s no eddies formed in the motor mount tube

Belts are new to me. I’m a long-time chain bike rider.

It uses a two-way throttle with a mid-drive which seems rare.


I’m hoping to find a two-way throttle that allows more degrees of rotation accelerating instead of the 50/50 split acceleration/brake it has now. Please tell if u have advice.


The bottom bracket flexes when standing on one leg and the belt will move across the big unflagged pulley. It has 2mm extra room to move across the pulley but should’ve made it 4. Couldve gotten the pulley made with flanges but didn’t because of possibly seemingly obsessive goals of better efficiency and less noise and wanting to assure it was aligned and not rely on the pulleys. I rarely ride standing on one leg so likely wont change anything.


Wish I had the frame made longer and would feel more secure at higher speeds…30mph high at least. Wish the bottom bracket was lower.

Wish it had 1 1/8” headtube and I had to have external bearing cups made so can use 1 1/8” fork. Thank god for that possibility and needing a 1” fork is ridiculous. I glued the cups in and were a slide fit.

The saddle is pure full carbon. Pure full stiffness. Ridiculous. One day I’ll probably get something but in this upright position it’s not bad. Kinda nice.


7:1 gear ratio
83100 motor. 69x50 stator. .15mm laminations which is super thin. I swapped the motor’s hub to add big bearings. the shafts that came with it are loose at 11.95mm for ease of assembly I guess and produces annoying vibration noises at 8mph and 12mm shafts in the mail. Retaining fluid, even the thick kind, didn’t work with the out-runner requiring sliding the shaft through both bearing and it rubs off. Also tried using a center punch tool. That does work at holding the shaft in the bearings but it’s a delicate job and I went into it too fast. Should’ve set the center punch to low force and the dents and rises I made on the shaft compressed the bearings and didn’t spin smoothly. The coming shafts are as short as possible but the shaft length as it is here isn’t an obstacle for feet.

Locking bushing is very nice, and solid, and simple.
Gt3 belt is the best these days. Or gates gt4 or whatever. Most torque. Quietest. It is very quiet.

Track rear hub uses an aluminum adapter to fit 144 bcd chainrings. The front chainring is 21 teeth and all-n-all it’s surprisingly quiet. 3/8” chain.

The freewheel just fits the smallest chainring bolt pattern



I can stick my fingers into the motor and touch the windings. It’s very nice to see how things heat up and also see the heat leave very fast. I had planned to add some forced air or water cooling from the seatpost but it stays cool enough.



Flipsky 75100 aluminum esc with no limits firmware programmed to 200 motor amps but doesn’t go over 55 and the motor saturates then and only 45kv

24s3p lifepo4 k2 26650 cells. 87v full charge. Potted in 60D polyurethane

 

[larsb]

83100 and .15 mm lams, did you measure them? Who’s the seller/manufacturer of this motor?
(i might get one for my next build)

 

[Hummina Shadeeba]

Measured and was accurate

Ant Innovation AT 83100 9.5kw Brushless Motor with Watercooling System

The new design 83100 Brushless Motor with Watercooling System for Electric Jetboard. The stator is made of 0.15 Kawasaki silicon steel by special process. Improve power and torque. Reduce heat generation. The efficiency is greatly improved. The maximum power reaches 9500 watts, the continuous...

www.antinnotech.com

They will sell it in parts and unwound!


I think this bigger size motor using just 12 teeth and 14 magnets makes it rattle at a certain speed and the rotor gets pulled back and forth a lot when cogging. Maybe not an annoyance if you don’t put the motor in a sound enhancer like I did. it’s also very hard/impossible to get retaining fluid on the nearer bearing and shaft. I bought more shafts assuming they weren’t truly 12mm but they are. I’ll be using the center punch but cautiously

 

[larsb]

Thanks, that’s a nice motor. I might do a wind on one if i ever get done with all the efoil tinkering.

With the thin lams and a 7 Nm conservative torque it’ll get you a lot of oompf for the dollars.

 

[larsb]

i wonder regarding the saturation you write about above, i’ve seen 80100 in 130kV start to saturate at about 150A, with respect to your kV that’s at roughly 50A - but the knee of the torque curve at this level of saturation isn’t very pronounced.

Therefore I think your loss of increased torque above 55A is coming from something else than saturation. Do you get a similar performance with different controllers?

 

[Hummina Shadeeba]

I have a couple flipsky 75100 escs and will get another of the same bike going with one of them this week to see. Those are only escs I have that can do 87v.

why would the esc only put out 55amps when I go full throttle up a hill when it’s set to as high as 200 motor amps and 140 battery?

 

[larsb]

Probably a hidden setting somewhere in vesc tool.
Similar issue on the efoil forum was this:

 

[Hummina Shadeeba]

Hmm interesting and I’ll see if that does it. Nice find.

I’ve been kayaking on the sf bay for the last two days and looped by groups of rented efoils. They use me for their games. I like them and I’m tough to please being raised on quiet old wood sailboats. kids these days I’ll tell ya…. No not really and more so I’m finding them all the same speed and it’s too slow. How fast your vessel go?

How much torque and how is it relate-able to bike torque?

Today was looking at a sunk boat’s mast sticking a foot out of the water at low tide and agreed w my associate an efoiler or a boat is going to get it. There’s so much stuff out there to hit..is sonar integrated?

 

[larsb]

It goes about 30 kph, mostly because i don’t go full throttle
It’s got quite nice torque actually but you can’t just floor it and take off, the propeller starts to cavitate and loses thrust then. I’ve crashed my board a few times, hitting underwater rocks mostly. nearly drowned and ended up on the ER after hitting my head on a rock two years ago.

 

[Hummina Shadeeba]

I think a full grip throttle and even a half grip throttle is a poor control especially with a bumpy course as it’s easy to unintentionally twist the throttle as it’s so sensitive if the bike has decent torque (even more so a problem with the limited travel of a two-way throttle). Next bike will try to use stress sensors on foot pegs leaving the hands fully free for maneuvering, with a braking peg on one side and throttle on the other side

Grin used to sell a stress sensor kit but don’t see it anymore. Any other leads? Any links to others who have done similar?

 

[MorbidlyObeseKoala]

I always wanted to try the thumb wheel throttle from the boosted Rev scooter. You roll it one way for acceleration and the opposite way for regen, similar to the electric skateboard remotes. Obviously everything takes some getting used to on rough terrain but I thought it was a really neat, compact design.
Thumb wheel throttle

Also wanted to ask about your 80100 motor. How magnetic is the outer case? Does a nail or other magnetic metal stick to it?

I purchased a really cheap one a long while ago with the idea of mounting it in an old motor casing as protection (open on both sides for airflow obviously). But I realized trying to test fit it the other day that I might rob some efficiency by having a magnetic case in close proximity introducing more drag/heat. Haven't had the chance to try it out yet back to back but it seems like a possibilty.

 

[Hummina Shadeeba]

I always wanted to try the thumb wheel throttle from the boosted Rev scooter. You roll it one way for acceleration and the opposite way for regen, similar to the electric skateboard remotes. Obviously everything takes some getting used to on rough terrain but I thought it was a really neat, compact design.
Thumb wheel throttle

Also wanted to ask about your 80100 motor. How magnetic is the outer case? Does a nail or other magnetic metal stick to it?

I purchased a really cheap one a long while ago with the idea of mounting it in an old motor casing as protection (open on both sides for airflow obviously). But I realized trying to test fit it the other day that I might rob some efficiency by having a magnetic case in close proximity introducing more drag/heat. Haven't had the chance to try it out yet back to back but it seems like a possibilty.

I was worried about the magnetic field escaping the bell and you can see the motor is very close to the frame (and will be closer as the belt has stretched and need to tighten it), but this bell is very thick steel and barely any field escapes. I’ve run the motor without any tension in the frame at highest speed and the current draw was pretty small but I don’t have good tools for measuring. I’d like to make a hallbach/carbon rotor someday to lighten it and see how it performs differently

I’m liking my two-way half-twist throttle and used to it at this point having used it for years with different bikes.

 

[MorbidlyObeseKoala]

Found one at a better price! Still a little pricey but not >$200. They also have an option with integrated buttons that look pretty slick for whatever you'd use those for either on the controller or for lights or something

Two way throttle SPIN-Y2 for diy escooter diy ebike

Spin-Y2 Two way throttle for diy escooter diy ebike Electrical Spec: Maximum Hand grip, specially at full throttle! Bidirectional operation (forward accelerate, backward e-braking) Remapped 0-3.3v signal, extend the hall range to get more interference immunity, and safe for VESC and similar...

spintend.com

 

[Hummina Shadeeba]

Found one at a better price! Still a little pricey but not >$200. They also have an option with integrated buttons that look pretty slick for whatever you'd use those for either on the controller or for lights or something

Two way throttle SPIN-Y2 for diy escooter diy ebike

Spin-Y2 Two way throttle for diy escooter diy ebike Electrical Spec: Maximum Hand grip, specially at full throttle! Bidirectional operation (forward accelerate, backward e-braking) Remapped 0-3.3v signal, extend the hall range to get more interference immunity, and safe for VESC and similar...

spintend.com

Wish I could try it for a day before buying. I’m imagining using the thumb like that for a long ride could be exhausting. I almost bought it.

 

[nicobie]

That's a really interesting bike. I didn't know that you'd fallen so far off the ebike cliff...

 

[Hummina Shadeeba]

That's a really interesting bike. I didn't know that you'd fallen so far off the ebike cliff...

I have one more frame and all the needed parts to make one more bike if u want one. I think ur in the area

I started making skate hub motors. Broke my collar and really I’d always been a big cyclist.

After finishing this dirt bike I’d like to convert a van.

Electronics n batteries are getting cheap and I finally have some money.

And selling this new gravel bike. 55mm top tube

 

[MorbidlyObeseKoala]

Wish I could try it for a day before buying. I’m imagining using the thumb like that for a long ride could be exhausting. I almost bought it.

I do too, I have seen a few people say it was less taxing than the traditional thumb throttle but I am sure it eventually boils down to preference. I suppose it is less strain to roll the button left/right rather than push down/forward, seems like it would be less prone to jerky movements over bumps.

I think they also advertise those add on buttons as latching so you could set up cruise control if you're into that. I don't currently have the time luxury to do a long enough ride to want cruise control or really very many long straights at the same speed but obviously if it has been marketed as a feature, a lot of people do set that up.