Bafang Ultra, Phaserunner + CA with custom frame

Hello everyone,
inspired by Daxxie (https://endless-sphere.com/forums/viewtopic.php?f=6&t=96212 ) and JPC6000 (https://endless-sphere.com/forums/viewtopic.php?f=28&t=95671&hilit=bafang+ultra) I decided to build something similar. I have a nice workshop with machines etc. as I have been restoring classic motorcycles for decades (here's a link to a build thread of my seeley racer: http://forums.sohc4.net/index.php/topic,171911.0.html).
Why an E-bike? Same reasons as many of my age have: some overweight, need of physical training...

The building is always the fun part, therefore I made myself a jig and startet to build an aluminum-frame from scratch



Main profiles are standard 80x30mm U-profiles with 2,5mm thickness, no fancy 6066 or something. Seat tube came from a german supplier, head is 6061, made on the lathe.
I wanted flexibility with the battery, therefore the huge "box" as frame-triangle.
View attachment 1
The battery is from ali, 14s7p (52V, 19,2Ah)

Here is the raw frame after welding ( I did heat treat it already)


Edit:
Geometry is
Reach 440mm
Stack 626mm
Head Tube Angle 66,5°
Seat Tube Angle 74°
Wheel Base 1246mm

The forks is a DNM USD-8, damper DNM RCP-2 and the rear suspension parts came from an old Intense M1 downhill-bike. I know that this taiwanese damping stuff is heavier than Fox or suchlike, but I had to be careful with the costs for the project. I tested the forks and the damper in my old Cannondale Prophet and they worked really fine, both are good to tune and sturdy.
The whole process went fine until here. Now I'm struggling with the electrics

Without the great work of Daxxie and JPC6000 I wouldn't come far, that's for sure. I will post details later...

Let's proceed: to keep ahead of the cable knot in my head, I made myself a wiring diagram like those I'm used to from the motorcycles:



Please excuse the bad quality. The drawing is 100x70cm and my phone is shitty. I will try to scan it in the office and post again

Edit: Here is the scan:


This was a lot of work, but it was worth it. Everything worked from the very start, even PAS (with the 5.6k resistor) works flawless.

I'm now struggling with the configuration of the CA. I have the judder like daxxie, PAS doesn't deliver power as strong as throttle, I still have found no way to switch to a preset with an extra button ("cheat button" for the cops to cut off at 25 km/h etc.)

I rode it today for the first time! I started the project in september 2018 and now, it's on the road. Moments like this are the best!

As you can see, I managed to hide almost all the cables inside the frame. When I unpacked the Cycle Analyst and read the manual I couldn't believe it: all those cables and ugly JST-connectors around my handlebars! So I changed the few connectors that have to be visible to HIGO and extended the other cables to send them down into the frame.
But there's still so much to do...suspension is too soft, a chain with more links, chainwheel size, shorter stem, pressure point of the front brake, mudguards...and I'm still waiting for the right reamer for the seat tube, so I had to improvise...
However, power delivery with thumb throttle is amazing, faster then you want in a blink of the eye! In the next weeks we will see what it is capable of.
cheers,
eli

elias said:

I rode it today for the first time! I started the project in september 2018 and now, it's on the road. Moments like this are the best!

Click to expand...

Gorgeous! You should be proud!

Thanks!

It's working smoother now. I still haven't found the time for a long trip, but did a couple of test rides to tune everything in (and lost pedal and a couple of screws in the forest while riding hard for the first time )

Chain has 130 links now, chain wheel is 48 teeth, rear is 10-Deore XT.
Reached speed so far in the forest was around 50 km/h, that was in 6th of 10 gears I will put on my motorcycle gear and look out for a quiet country road and try what happens in the big gears...
Here are screen shots of the config so far.

Hey Elias,

Just got back from a biz trip and found this posting by you.

Thanks so much for sharing this. I am a LONG way behind you on my build, but I am certain this information will save me hours of debug time in the future.

I cannot wait to hear how the higher gears run out in the country!

Gary (and everybody else) - some of those settings for the CA are obsolete, I have found better ones I will post new screenshots this weekend...
I tried to drive some distance with the above set-up on the street yesterday, but with the 48-teeth chainring (and 11 teeth as 10th gear of the shimano cassette) I reached 50 km/h in seconds. The 50km/h mentioned above I reached with thumb throttle without pedaling in 6th gear. But pedaling on the streetin 10th gear still felt like I had a big turbo-diesel under my seat AND the pedaling frequency was mad. So I changed to a 55 teeth chain ring. The bike still pulled like mad and as I went uphill somewhere between 45 and 55 km/h the new chain (Shimano HGX) broke. Pushed home, fixed the chain, second try - chain broke somewhere at another link
As the longer ratio creates a bigger torque on the chain, it can't withstand the forces, I believe. Maybe something else was wrong, as Karl Gesslein says in his Blog, that he always uses 10 gear derailleurs, but I checked chainline, position and tension of derailleur etc.
My conclusion: I bought a Sturmey Archer RX-RK5 IGH with a 1/8 chain, a 17 teeth rear and 55 teeth front chain wheel. Together with the IGH (longest gear ratio is 0,65) that would make a final gear ratio of around 0,2 which should be good for 70 km/h or more, if you think what RPM-reserves the motor must have that it made 50 in the 6th gear as well...
At least, brakes and suspension work great now. The whole bike has a weight of 32 kg :wink: and that weight gives you a quite solid feeling.

Here's the new config. Throttle response was too slow, so i raised the Fast Ramp Uprate, and shifting time was too short, so cut off for 0.4 sec now.



Cheers, elias

Thanks Elias!

I have my bike built in my garage now minus wheels and gear set. We got a mock up kit from the Rohloff distributor and just verified the fit of the unit! Today we ordered DT Swiss H1700 front 30mm and matching rear rim with
Rohloff 14 speed IGH. With more than 500% range, I will start with a 40 tooth front and 16 tooth rear then see where I am at.

I will start out with your settings above but I expect I will need to fine tune for my 60 volt triangle with 50 amp continuous BMS.

Gary, sounds good. I went for the Sturmey 5 because Ron of electricbike.com suggested that one shoudn't have too many gears with a lot of power:
https://www.electricbike.com/mid-drive-kit-igh/
I used a SunRingle MTX33 rim with 2,6mm spokes. Had to widen up the spoke holes etc. I used the thick spokes because the 2,0mm ones moaned and creaked all the time while accelerating and braking even though they were under a lot of tension.
elias

Just found this thread and all I can say is: WOW :thumb:
What a nice build! More photo's would be appreciated

Hey Elias,

Thanks again for the setting starting point! I have loaded your settings and I have the bike completed, just wating for the Rolhoff and wheel sets to arrive in two weeks.

Here are a couple of photos from my build. If I have time this weekend, I will take a set of 27.5 wheels off another bike and use them to fine tune the settings before my correct 29er wheels show up!

Frey HT 1000 waiting for wheels!

So you're hiding the cables,phaserunner etc. in the frame box and the battery sits in the triangle then? :thumb:

I have everything together so far, but new problems arise... It doesn't matter how tight I bolt the rear wheel, it moves with the chain pull (the right side slides to the front till the wheel touches the left side of the swing arm. Arrrgggh. My swing arm has a custom width of around 150mm so that I could fit everything I want with adapters and as I made a spacer from aluminum for the chain side that functions as a hanger as well, I'm afraid that this aluminum-hanger glides on the aluminum swing am.
That means I have to make some tensioner for the rear wheel as in motorbikes. At least it's raining anyway since days and continuing...

@ SlowCo:
I will post new pics when everything is working and presentable, OK?

Yes, my electrical goes into the frame cut out where normally the Reention Dorado Battery pack sits. All I need to fabricate was the simple cover! You on the other hand are a master fabricator and next to your efforts, mine are very meager!

My goal was to go beyond the Doradra pack limit of 80 cells which limits you to either 52v17.5AH or 48V 21AH.

Now I will have 60 volts and 50 amps for 3000 watts on this build. I chose the frame to use narrow 2.2 MTB 29er wheels on a HT frame. If everything goes well and I feel the motor can take more current, I will then build a full suspension version but instead of 60 volts 28AH, I will get a 72 volts version and increase BMS from 50 amps to 60 amps to see if the Bafang Ultra will handle over 4000 watts!

I have already ordered the Ultra replacement for when I find the limits of this one by "letting the smoke" out of the motor.

With all of the information and help I have gotten from this site, I figure that the least I can do in contributing to the general knowledge fund is to establish the upper limits of the Bafang Ultra! With the controller out of the drive I think it may take the heat! I will be monitoring the temperature closely thru the CA temperature readout.....

BTW: Elias, how fast have you gotten your work of art to? 60KPH?

Well, if I was a master fabricator, things would work!
Gary, I didn't try on the street, the bike is still in my basement workshop. What I did do was pulling through the gears with thumb throttle while the bike was on the montage stand. The speedo showed 92 km/h at full RPMs of the Bafang - but of course with no load If it's going downwards for a long time, maybe that would happen on the street as well, but I don't feel very comfortable about it! I can see that you are a motorbike owner as well. Do you really want to put 4000W and more into that Frey frame? Or their fully frame? I mean, it looks nice for sure, but I doubt that it will be rigid enough, really! Think of Daxxies Video (where he shows the judder while accelerating) and how the titanium frame bends under 2500W. I bet your alum frame will bend and crack without some reinforcements.
The reason I went into custom frames in motorcycling was that Honda and Kawasaki built great engines in the 70ies, but bad chassis. I had many critical moments on the street because a frame couldn't handle the power of the engine. OK, here in Germany, we are talking about those fast curves on the autobahn which you want to take with 200 km/h
But those experiences were actually the reason that I went for my own frame for an ebike. I had seen the frames of some chinese manufacturers at the Alibaba site but decided that they are not rigid and sturdy enough for what I wanted to do. On my build everything is thick and solid and I didn't care too much about the weight. I wanted the Chassis bullet proof...
For example at first, I bought a Votec rear triangle for the bike. Votec builds top class mountain bikes, with state of the art engineering, but they are also known for lightweight builds. That old Intense swing arm in comparison is massive! Thick tubes, fat ends, bigger bearings etc. Even though it is battered, it is much sturdier than the perfect and high tec looking Votec swing arm.
Well, those are just some thoughts...

Anyway, thinking about all that standing in the workshop I decided to make some pics for y'all:

Here is the right rear end with the custom hanger


What I will do is weld up a lot of material to the rear ends of the swing arm, make a new hanger into which goes a M5 screw showing backwards through a counterpiece with a nut behind. This will keep the right side of the axle in place...

Here is a pic of CA and front light on their aluminum mount

View attachment 2
With that arrangement I have the shortest way into the frame for the cables coming out of the CA and the handlebar looks clean and bicycle-like...

Here is a pic of the rear wheel. I simply welded on alum rings with threads to fit a Zefal No-Mud mudguard. Easy and clean look.


Same mudguard on the front. But as it is an USD fork, I was in trouble. So I made those alum parts which mount on the brake adapters. Thankfully the DNM USD-8 has brake mounts on both sides...Why not mount a typical USD-mudguard? Because I hate the looks of mudguards under the lower triple clamp. When BMW and others started building their big enduros in the 80ies, we used to call them "duck-beak-bikes" (in german "Entenschnabelmotorrad", not a beautiful word as well)

Btw, the build started as an enduro/DH-bike but with that speed potential I decided to convert it to a commuter after my first ride. So the front will get a Schwalbe Moto-X tyre as well.

What required most of the time while building? Of course building the jig and making the main frame. But beside that it was the lid of the box


It was critical for the statics of the frame (not that I would do any calculating or CADing or clever things like that :wink: ) that the upper area of the frame is very stiff. But as the lid had to be there, I had to mill massive parts from 10mm thick aluminum that are hold together with M8 screws. The lid was 2 weeks of milling. Keep in mind that I have a job and kids and wife and house so that was from 8 to 11 in the evening and on the weekends. But still, I stopped counting how many times I had to re-clamp the thing on the mill!
I love working on conventional machines. I can see of course the benefits of CNC-machines, but I would hate the thought of sitting at the computer for days to construct something like this (without any experience). Working with my old mill sometimes feel like carving wood. You do something, look at it afterwards and decide the next step. The final product is not necessarily what you planned in the beginning - it is better!

Cheers, elias

Hi Elias,

I find your postings to be greatly enjoyable! Your work is really, really nice. Your skills are amazing! My background is metal packaging manufacturing as an EE. I have many years experience with German engineering. Your bike is built the way I would build it if I had your skills: Well Engineered and twice as strong as needed.

Yes, I am a motorcycle nut for my whole life! In 1974, when I graduated high school, I rode a 750cc Kawasaki two stroke triple. Those things were crazy fast, stock, and we would port them and add bigger expansion chambers and bigger jets! We called them the "flexi Flyers" because the frames wiggled like a wet noodle when we put all that power to the rear wheel! That was the first time I went over 160MPH on a bike a little over 250kph. My best was 205mph on a Hayabusa that was chipped.

For me I think the Frey HT frame will be OK. I will be looking for straight line speed on this, not enduro or even cross country. Once I establish the limits of the Bafang Ultra, I will ride it more or less in a safe and sane manner. :lol: I will not be trying to pull the rear wheel out of the frame with massive torque. (like you my friend!) I will roll on slowly.

I have looked at frames of similar design to yours as seen on HPC, Alibaba etc. It's just that it seems too much like a motorcycle and I am looking for a bicycle experience. Perhaps my Frey frame will wiggle like a wet noodle and take me back to my youth! At least before it self destructs.

Please keep posting! I find myself looking forward to the next chapter of "Elias' build"!!

I hope to do a little testing this weekend and fine tuning my CA and PR settings. I ride a 17 mile loop here on the California Delta with water on one side and farmland on the other. I should take a photo to show you the water side is higher than the farmland side! Kind of like you see in the Netherlands. Not too technically challenging but easy on the eyes.....
BR,

Gary

garyal1 said:

BTW: Elias, how fast have you gotten your work of art to? 60KPH?

Click to expand...

My Ultra Phaserunner goes exactly 60km/h with 2250W @52V

I have a 72V 50A battery now but cant get autotune to work properly at 72V.
Broke 2 chains experimenting with 3000W @72V
Still needs some finetuning.

Daxxie, I love your build as it is really clean! How is it then, accelerating out of the curves? Any bad load change behaviour? Rear wheel wiggling like the 750 two-stroke Kawi of Gary or my stock CB750 SOHC :lol: ?

Concerning tensioners:
Once again I found out that I'm totally clueless about what already exists in bicycling. The tensioner I imagined already exists:

its from problem solvers. Thats what they sell - great products!
My last bicycle I built up before this was a steel framed Gitane racer with Campagnolo derailleur. That was in 1983! Things have developed since then...

However - hopefully, my build will be on the road this weekend (if it doesn't rain) and I will find out one thing or two...

elias

Hi Daxxie!

I hope you got my thanks on another post. All the work you guys did figuring out the Bafang Ultra on other posts is what actually convinced me to pull the trigger on building my own high current bike, Thank you again!

60KPH at 2250 watts with 52 volts pushing sounds good! I wonder what 60v50A 3000W will give me? I am fat! 225lbs.... I will be lucky to match you!

The rear axle adjuster Elias shows looks perfect to me. Just NOT in black!

Although I have not yet even ridden mine one inch as of yet, I have been having a lot of fun learning about the Grin PR and CA. trying to match the craftsmanship of you guys.... but failing miserably compared to you guys. Still it is a lot of fun!

Daxxie, how hot can you get that Ultra running with throttle pegged for a few miles? Hot enough to cook an egg?

I am just now starting to look for a 72 v triangle with 60 amp rated smart BMS. Here is the company from China I used for the 60 volt 50 amp 28AH I have now: Here is where I bought:

https://cn1520893666wtzi.en.alibaba.com/productgrouplist-810398942/Mountain_Bike_Triangle_Battery_Pack.html?spm=a2700.icbuShop.98.6.3bda590cOiJg2e

New drop out with wheel adjuster ready to go:



If only the rain would stop...

Well, I put a set of 27.5 wheels 10 speed Shimano on the bike for set up purposes. I do have a small "judder" on initial acceleration, but I will ignore this for now as it is not too bad.

I have the current limits in both PR and CA3 set at 60 amps. My battery is 60 volts 50 amp BMS. I also have the watt limits up over 4,000. Bike runs fast! However, it seems there is a 40 amp limit somewhere because the bikes stop increasing current at 40/41 amps. about 2500 watts.????

This is an Alibaba battery and I am wondering if maybe they did not give me a 50 amp BMS as ordered, but instead gave me a 40 amp BMS.???? Any thoughts on how to tell what is holding me back on current?

Speed topped out abound 38 MPH, but I could probably gotten a few more out of it....