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Mini Hiryuu - Mid power ebike

GRIN did give me this advice almost 3 years ago:

141 is only 3mm on each side compared to 135mm which is the standard for rear slotted drop outs.
You can make any of our solid axle style motors work for your bike. I would recomend one of the following.
1) Our GMAC geared motor which has excellent torque as well as a locked clutch for regenerative braking. The 10T wind would be a good option for extra low end torque.
2) The Nine Continent RH212 is a really robust direct drive motor. It is completely silent and would have virtually no servicing required.
Hey if the axle diameter is a fit then i don't see any problem with going to spacers and possibly losing your rear mechanical brake - the regen on either of these motors can be pumped up to levels beyond that of a 203mm mechanical disc. I'm thinking you also lose a few gears but you won't need many.. :)

GMAC should probably be driven by an infineon clone because apparently the phaserunner does drive the motor but stutters at higher RPMs. Cutler mac still sells infineon clones and they're excellent controllers. The extra noise of the infineon would be above your tolerance threshold htough.

RH212 is the budget sleeper motor here; i'm too picky about efficiency to try it
I don’t see the GRIN all-axle overheating in a 24” on steep climbs in the motor simulator
Hey if it works in your situation.. that's all that matters.

We can get down to 80% efficiency at a 5% grade.


But if we swap to 22", we shift that pain point to about an 6.2% grade. ( going slower as a result of the wheel size difference helps a bit too )


If you don't have rollercoaster like terrain like i do in the mountains, 24" will do fine.
Build update!

em3ev 'king shark' is finally here, it's basically just a Reention DP9 like ebikes.ca's, but with a bluetooth BMS.

I have 24" tubes and a 60mm XT connector on the way.
Should have the bike running with the all axle motor very shortly.

As for the bikee mid drive, i'm still waiting on parts since the 11th... it's being thrown in to the back of my motor evaluation queue.
As for the bikee mid drive, i'm still waiting on parts since the 11th... it's being thrown in to the back of my motor evaluation queue.

Wait, you ordered parts from Bikee on the 11th and they just ghosted you? I had an offer to buy my Lightest motor, but mine is just going in the parts bin for now.
Nah, i actually had a consult afterwards that was great.

I got an email that PAS sensors were in on the 26th and they were on some holiday, but they're about a week past the date they said would ship.
Mini hiryuu is coming together!

I bought a 24" front wheel with disc brake but decided i really didn't like the look of it.
Put a 26" x 1.95" up front and i have a 24" x 2.4" Kenda cargo tire out back.

The front tire measures as 25.5" and the rear measures 24.5". At a distance, the tires look like equal size, and i'm pleasantly surprised at how non-goofy the 24/26" setup looks.

I plan to run the rear tire at -10 PSI versus the front so that it can contribute some rear 'suspension'. Fingers crossed that we have adequate ride quality at 30mph between the tire, smooshy seat, and suspension seatpost... despite the slightly reduced tire diameter.

mini hiryu.jpg

My cannondale recumbent had a 113mm wide bottom bracket and 175mm crank arms. I decided to reproduce that setup on this bike because my long legs loved it.

Have a 48T chainring on it but it probably needs more like a 56T. BB might actually be able to get narrower too. Will ride and adjust from there.

mini hiryu 2.jpg

Without the front fork compressed and with some low profile pedals, i still have a little over 4 inches of ground clearance, which should be adequate for road riding.

If i need more, it's probably not much. There do exist 24 x 2.6" tires, and i could easily get a taller front tire to help add clearance if i'm wrong about this.

What's left?


[ ] Find out how the heck to get a ebrake lever hooked up to this Phaserunner v2, since Grin is having problems with their phaserunners and i can't buy a new one.. Sent Grin an email. New Phaserunners are out of stock..
[ ] Waiting on delivery of the satiator charger cable and triple bob.
[ ] Support bracket for the frame bag to push it forward so more battery weight sits over the front fork.

Not Crucial:

[ ] Buy flatout sealant for rear tire.
[ ] Custom rear rack that takes advantage of the smaller rear wheel, allowing the cargo to sit lower and more towards me for a better center of gravity than a typical 26" rack. Or i may modify an existing one.
[ ] Rear panniers to hide the motor.
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Pls be careful with -10 PSI in the rear!
Less pressure is appropriate for a fatter tire. The cross-sectional area of a 2.4" tire is about 1.5X that of a 1.95" tire, so anything up to about that inverse ratio of pressure is good. However, rear tires almost always carry more weight and therefore should have higher effective pressure.
I'm talkin' 40PSI up front ( we have an air shock up front, who cares ) and 30PSI out back.
Rear tire is 24 x 2.4".
I'm talkin' 40PSI up front ( we have an air shock up front, who cares ) and 30PSI out back.
Rear tire is 24 x 2.4".
To have the "same" pressure in a 2.4" tire as a 1.95" tire at 40 psi, the fatter tire would be at 27 psi. Because the "more pressure in back" rule applies, you're doing it about right.
Makes sense!

I'm a bit crabby, the build is stalled because i can't get a new phaserunner ( continually out of stock ) and apparently running a ebrake lever on my ~2015 era phaserunner without an era appropriate CA is experimental.

I also read that the L10 connector can only handle 85 phase amps for a burst.. the manufacturer rates it for 45A continuous:
Suzhou Cusmade Electronic Technology Co., Ltd.

This means that during acceleration and hill climbing, i'm wasting some % of my energy in the wires and also the battery, which is saggy itself.

It sounds like the motor could benefit from 4mm hobbyking bullet connectors on the phase wires as usual and possibly upsized wires.

Simulator says that for a 24.4" tire, peak ( saturated ) torque is the following:
50A 120A phase 3077 controller: 77ft-lbs
Phaserunner: 65.9 ft-lbs

There's probably another 5 ft-lbs of torque potential with thicker cabling; even if i never run that power level, the couple percent efficiency i get is worth it because a 19.5ah 52v battery is going to be saggy, and i want to utilize it right near the point of what we'd considered abusing the component, and no more..

..off to see if i can get a controller from cutler mac.
Grin got back to me. I had to escalate the question up to level 10 tech support ( Justin )

Apparently there is a hidden blue wire in the throttle connector of the Phaserunner V2. A on-off brake throttle can be wired between the black ground wire and the blue brake wire.

Really glad i didn't have to get another controller because Grin is currently out of phaserunners while they are working out a technical issue with the current batch of controllers.
Did the modification. Next step is to program the controller and take 'er for a test ride.

That Triple Bob can make for a nice tight fitment of these 52v 20ah batteries. I really like it. I would have preferred to get the battery up front even more but the water bottle holes were really low on this bike. Good enough.

I have a way in mind to put the battery and controller in a frame bag and get away with it. Mini Hiryuu could end up a lot stealthier than it's predecessor.

2024-05-19 23_16_05-Window.jpg

Honestly the contrast between the front ( 1.95" ) and rear ( 2.4" ) tire looks goofy. Despite the regen doing most of the braking, i could also go for a disc up front in the rare instance that the regen fails.

Have a disc wheel and 2.2" tire on the way for the front.
Yes i have plans for a rack that sits a few millimeters above the smaller rear tire for a very low center of gravity on the cargo. I will add panniers mostly to just hide the motor. :)
Okay, got everything wired..

Cycle satiator prematurely stops charging the em3ev battery every 30 minutes on average, it says it shorted, and i have to force start it again. This happened from 20% SOC as the em3ev battery was shipped all the way up to the 80% i charged it.
I have brand new satiator battery charging cables so this can't be the problem.
The satiator is 10 years old but has very little use.

Phaserunner V2 autotune worked, throttle and brake line show expected voltages, both work, regen works, regen stops accelerator.

System check complete.

Acceleration to top speed on 80A phase / 30A batt is good. About 15 seconds to get to a top speed of 33mph w/o heavy pedaling. Would prefer a little more power.

Motor is incredibly quiet and throttle is amazingly smooth compared to my old infineon clones.

But out in the field, weird and dangerous things happen:

Throttle will suddenly stop working after a few uses, CA V2 displays 11000W, throttle then stops working. Turn off battery, turn it on, then everything is working again... rinse repeat.

I tried pedaling once after this event, the throttle started working again after a while, then the bike went WOT. The ebrake didn't stop the power. I had to grip the front brake super hard and jump off the bike then lift the rear wheel to prevent burning up the motor.

Got back home, checked the voltages of the throttle and brake, everything looks right and responds right, settings seem correct.

Throttle voltage: 0.82v resting, 3.83v fully engaged
Brake voltage: 3.43v resting, 0v engaged.


Using the following settings which seem rational.


Controller & throttle background? had 0 miles on it, never powered up, sat in a shed outdoors for 5 years, in a closet for another 5. No rain intrusion. 0-100F temperature swings and 20-100% humidity swings while in the shed. But the components should be sealed and designed to not suffer the elements.

Ok, the components are 10 years old, close to 1st gen grin components. But this is all very frustrating. I also cannot get a new phaserunner from grin.

Very frustrating.

Sent an email to grin to see if they can help. if i run this controller again, it will be oriented so i can easily yank the power cord.
Looks like we have a save.

MAC motor tech / cutler MAC didn't respond to their contact page, but did respond to an email to both addresses on file.
They can get me a 3077 12 FET infineon and a 3 speed switch. They say it has sinewave function and is an eb3xx.

I'm a month out from getting one, so the only sane thing to do is to reuse this bike as a test platform for the lightest.bike mid drive.
We only have a few weeks left until it gets to hot to ride out here for 3 months.

Have a 26" rear ( with cassette ) and front wheel ( with disc ) coming now.
Well, we have a curveball.

A fine tuning of the throttle dead zone, and.. i can't reproduce the behavior at all now on a 2x longer ride.
It's unnerving to know that some combination of settings can result in WOT with no ebrake lever to stop it. At least there is a warning sign. It's possible that the programming software is missing some safety checks against user stupidity.

In my case, this was the first time programming it and i'm used to simple AF to program infineons. I did read the manual.

The CA 11000W problem stopped happening and the CA behaves as normal now, except it has a high amount of wattage reading drift.

It looks like i can wire an on-off switch. This sounds like a necessary insurance policy.


I inspected the CA for moisture/corrosion/dust and the thing was flawless inside.

I think it is reasonable to think that my connectors are suspect considering the amount of time the phaserunner and CA spent in a dusty environment. The response from ebikes.ca implied this might be the cause.
Okay, riding impressions.

The 2.4" rear at 25psi is pretty nice and i am VERY surprised at how well the bike rides on our crappy pavement.
I hit a top speed of 34mph and it felt confident over the crap.

I really like how smooth and quiet the phaserunner is.

Running this motor at 90A phase, i find that the power is allright, but it can take a while to accelerate to 30-34mph.

Comfortmaxxing turned out well. You do feel the aftereffect of bumps when dropping off the curb but it's super damped by the seat post and the gel seat and the seat's elastomers. The front end is really plush, so if you kind of dive into a bump with the frontend hitting it first, you can reduce the impact on the rear.

The Reention DP9 battery case is acoustically unimpressive, it has a noticeable amount of play between the battery and connector plate and likes to clunk on every bump. I think some strategically placed rubber could improve this.

The suspension seatpost is spring based and has a clunk during motion as it hits a non-existant bump stop. I put the cover on and let's see if that improves it.
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Also here's a reality of using a bike that cost $299 new. The water bottle attachments are crooked AF.
And yes, this battery is mounted totally correctly.

Yeah... we're going with a frame bag.

2024-05-21 13_58_48-Window.jpg
Moved the triple bob up one water bottle mount. Wow, you can get the battery quite forward. But the battery isn't any less crooked. What a bummer.

I might end up building a custom battery support to get around this.

2024-05-22 00_44_46-Window.jpg
Moved the triple bob up one water bottle mount. Wow, you can get the battery quite forward. But the battery isn't any less crooked. What a bummer.

I might end up building a custom battery support to get around this.

View attachment 353335

How heavy is that big battery and how many screws hold it down? A full 24 oz water bottle is 1 lb 10 oz. I have a small 4.5 lb water bottle battery which needs the mounting points relocated with 2x 5 mm Rivnuts (weaker than factory brazeon) and I am worried if that's too much weight/ stress.
A full 24 oz water bottle is 1 lb 10 oz. I have a small 4.5 lb water bottle battery which needs the mounting points relocated with 2x 5 mm Rivnuts (weaker than factory brazeon) and I am worried if that's too much weight/ stress.

Most battery rails that mount on bottle bosses have more than two places to attach them. Often there are three or more mounting holes, and in most cases they're slots that can have a fastener at each end. So if you know where you want to install it, you can add more rivnuts.

I mounted my Hailong pack (when I had one) with three clamp-on bosses like these:

Mine were larger in diameter for 35mm tubing, but looked exactly like these. I used a plate of aluminum to bridge between them and reinforce the Hailong plastic rail, but washers sandwiched between the clamp bosses and the battery rail would be enough support I think.