PaulD's lightweight mid drive development

Very Good, to have different plates for the different style frames . :thumb:

In regards to someone saying that 350 watts in enough ... No it is not.

I live in a Hilly area , I often am seeing over 1k watts on the Cycle Analyst when going up hills.

Add to that at my Age I have arthrits/ inflammation in my knees, ... and weak cardio vascular system.
If I did not have these conditions I would not need a e-bike in the first place ,
So
Higher power possible with higher voltage packs and A throttle are must have features .

( I already use XT 90 's on all my wiring harness that connect the battery pack to controller on my current conversion. )
 
ScooterMan101 said:
In regards to someone saying that 350 watts in enough ... No it is not.
Click to expand...

I think we can all agree that 350W is enough for many people. It's more that a typical pro cyclist can deliver for an hour. I totally understand that not everyone has the fitness and mobility to pedal or they want to go motorcycle/scooter speeds. This kit is not intended for them.
 
How much will they run?
 
Wow, that's a really nice looking little package!
 
PaulD said:
\
I think we can all agree that 350W
Click to expand...

No we can't. If 350w is enough for many people it's only because they can barely ride a bicycle in the first place and 15 mph is terrifying. 350w sucks ass and is very SLOW! Professional cyclists aren't fast, regular humans are barely moving at all.

Your frame of reference is probably distorted by your love and skill for pedal pushing and bike control. 350W is more than enough to make bike control the limiting factor on technical terrain but so what? I would be more willing to accept 350W if the system was a lot lighter and smaller.
 
aCeMadMod said:
Nice work. How much dose the motor wight ?
Dose it use sun gears?
What are the pad things?
What cost of setup? And watts
Thank you
Click to expand...
The motor with ASI controller, wiring as shown and mounting plates is about 4.7lbs. The battery is about 4lbs.
Yes, it uses a planetary gear reduction (12.6:1)
I think you are referring to the controller cover. This just covers and protects controller wiring.
As noted above, total price for the kit (motor, controller, battery, freewheel, bb, cranks, display) is a little under $1500. Max power is 450W.
 
neptronix said:
Wow, that's a really nice looking little package!
Click to expand...

Thanks Neptronix! Trying to keep the wiring nice and clean is a challenge with kits that will be mounted to a wide variety of bikes.

flat tire said:
PaulD said:
\
I think we can all agree that 350W
Click to expand...

No we can't. If 350w is enough for many people it's only because they can barely ride a bicycle in the first place and 15 mph is terrifying. 350w sucks ass and is very SLOW! Professional cyclists aren't fast, regular humans are barely moving at all.
Click to expand...

Ok, I think we'll have to agree to disagree on this. :D
 
Very nice effort. Next time I'm down that way I'll have to check it out perhaps?

Two things,

1) It is too bad that Sempu etc. don't make an ISIS type bb. I have pretty much promised myself that I won't buy another bike without that interface, it is just plain superior to the tapered spindle and way more crank options out today.

2) No throttle? I just like to have one on board for the times when it becomes the best tool for the job.

Keep up the good work!
 
Bigwheel said:
Very nice effort. Next time I'm down that way I'll have to check it out perhaps?

Two things,

1) It is too bad that Sempu etc. don't make an ISIS type bb. I have pretty much promised myself that I won't buy another bike without that interface, it is just plain superior to the tapered spindle and way more crank options out today.

2) No throttle? I just like to have one on board for the times when it becomes the best tool for the job.

Keep up the good work!
Click to expand...
Thanks Bigwheel. Let me know when you are down this way, and we'll get you on a test bike.
1) - Yes, square tapered is a bit out dated, but sufficient for most riders. We have a lot of test miles on the Sempu, and they seem to be holding up well as long as you don't let your crank bolts get loose. We are using high quality Miranda cranks which help. I abuse it regularly on the trails here, but I am not very heavy. Heavy or very aggressive riders should wait for our ISIS or Cinch solution (working on it).
2) Yep, just like a Shimano or Bosch bike. I wanted it to be Class 1 legal, but the savvy DIY'er could certainly wire up a throttle. Settings on the ASI would have to change, but it's certainly doable. If there is enough interest, I would consider a throttle version.
 
PaulD said:
file.php
Click to expand...

Hey Paul, what's that cute looking battery package I see there!? :wink:

Big kuddos on getting a custom kit design from development into what is getting very close to full production. I love seeing people succeed in making their vision pan out, it's never an easy or short road to travel.
 
justin_le said:
Hey Paul, what's that cute looking battery package I see there!? :wink:
Click to expand...
:) That's our Grin inspired potted battery pack. 10S3P LG MJ1 cells with Grin's amazing full featured LIGO bms. It's potted in super tough UL 94 V-0 polyurethane. With our stealth quick release mounts it's a pretty tidy package.

justin_le said:
it's never an easy or short road to travel.
Click to expand...

Thanks Justin! I definitely underestimated the challenges involved despite my past experiences with new product development. So many hurdles with procurement, and tricky technical stuff.. I'm stoked to get these into customer hands soon!
 
On the first page you mentioned a theoretical max of 60Nm at the crank. Is that still the case?

Looks like a very clean lightweight kit! Very impressive! Can I get a quick test ride next weekend?
 
Hey All,
I'm stoked to announce that our pilot production run is now available! These first pilot builds will be available for a slight discount. Feel free to ask any tech questions here. I'll start a new thread in the for-sale section. I also have various ebike parts available in my online store. Ebike cranks, Sempu bottom brackets, and some sprockets for #25 chain.

pronghorn,
I'm working on a new dyno setup to do empirical validation of the crank torque. I've been experimenting with higher phase currents for the last 6 months, so we are likely exceeding 60Nm in the production config.
 
I am interested in how your custom freewheel will allow a mid drive to use the sophisticated Sempu "torque-sensing" BB...nobody else has that option....
 
spinningmagnets said:
I am interested in how your custom freewheel will allow a mid drive to use the sophisticated Sempu "torque-sensing" BB...nobody else has that option....
Click to expand...

Hi Ron, the custom freewheel bolts to the Sempu T4 sensor shaft with 5 M5 screws. All of the riders power goes through this shaft and that is how the Sempu measures both right and left leg output.
The Sempu T4 is normally supplied with a rigid spider that bolts to the shaft, but this doesn't allow for a mid-drive freewheel.
The custom freewheel uses big 50mm ID bearings so it fits around the spider and it's big external bearing without forcing the chainline outboard.
 

Attachments

  • sempu freewheel.png
    sempu freewheel.png
    179.6 KB · Views: 3,708
  • sempu freewheel CAD.png
    sempu freewheel CAD.png
    10.8 KB · Views: 3,708
agniusm said:
Very, very, very very nice.
Click to expand...

Thanks Agniusm,
Here's a pic of the custom wire EDM ratchet ring. I'm using White Industries pawls and springs.
Edit: I forgot to mention that there are 2 offset sets of pawls, so with the 40 tooth ratchet, we get 80 points of engagement.
 

Attachments

  • ratchetring.png
    ratchetring.png
    170.1 KB · Views: 3,592
I'm using White Industries pawls and springs
Click to expand...

All materials are not the same. I had the pleasure of meeting the owner of White Industries at one of the Interbike meets. Cheap steel "looks like" high quality steel. Not only the quality and consistency of the material can vary, but the case-hardening, and the heat-treating too...

White Industries is in it for the "long game"...high quality and low volume. They are the best available, and this was a good choice.

For a short time, I was a QA inspector for aerospace sensors at Barksdale Controls. We ran lifetime cycle-testing on samples of sensors 24/7, in the millions of cycles. Quality materials coupled with a quality design will last your lifetime.
 
Bigwheel said:
1) It is too bad that Sempu etc. don't make an ISIS type bb. I have pretty much promised myself that I won't buy another bike without that interface, it is just plain superior to the tapered spindle and way more crank options out today.
Click to expand...

Searching images on the web turned up an ISIS version of the Sempu, does not seem to be available for purchase yet.

https://www.aliexpress.com/item/32671603270.htmlbilateral-torque-sensor-transducer-433x367.jpg
 
I have a production kit and IMO it's a masterpiece of design and execution. The motor/controller, display and all attachments weigh slightly less than eight pounds and, since my bottom bracket and crankset weigh slightly more than two pounds, represent a net gain of less than six pounds. The battery and "cradle", which attach where the water bottle mounts on the down tube, weigh slightly more than four pounds. Also, there is an instruction manual online.
 
If you still need another tester, i have a pair of recumbents here, as well as some long 1-30% grades to scale.

400px-Salt_Lake_City_-_July_16%2C_2011.jpg
 
You must log in or register to reply here.

Similar threads

R
    • Like
L-Faster / Dome Motor 450W Mid-Drive Build
2
Replies
25
Views
3,053
DanGT86
DanGT86
C
Chimera”... Antique style E bike build, circa 1915...why and how
Replies
6
Views
913
classicalgas
C
R
    • Like
A critique of mid-drive riding recommendations (and hub drive criticisms)
Replies
15
Views
5,030
Bullfrog
B
R
Mid-drive PAS with stuck or non-existent freewheel/clutch gear
Replies
8
Views
867
richj8990
R
R
Dual chain/drive lightweight mid drive - advice needed.
Replies
1
Views
287
flat tire
F
Back
Top