2nd ebike and first built = I'm lost

Hi everybody I want to build a commuter for summer. I have a Voltbike Yukon for winter (generic chinese ebike I guess). I would like to build something smaller and more efficient for commuting. Ive been reading a lot of post on endless sphere and I would like some advices before I order something.

Desired max speed on level ground. mph or kph = 40-45 kph
Desired max range at what cruising speed. mph or kph 20-30 k
Preferred bike wheel size, or wheel size of bike you want to convert. 26 inches
Brake type of motor wheel. Disc
Rider weight. 140 lbs
Terrain. Exp: mostly flat / mostly road
Budget = 700-800 usd
Giant Yukon https://www.dropbox.com/s/6cronlujb19dk0i/yukon.jpg?dl=0


-The frame is small i can only fit a "shark pack". I don’t want to use lipo or something else.
-I need a PAS because I want to pedal most of the time. I really like the PAS on my Voltbike Yukon
-A geared hub is my first choice because it's small, light and it can freewheel.
-A mid drive might be an option but if it involves too much maintenance I'll pass because there are not many hills in Montreal.
-A hub is not interesting for me because it's too heavy and there's a drag unless someone can point me to a small hub with less drag (like the smart pie)
-1000-1500 watts peak should be more then enough.
- I would like to keep my 8 speed cassette.


So far my best choice seems to be:
BMS Battery
https://bmsbattery.com/ebike-battery/774-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
with this rear hub (which rpm?)
https://bmsbattery.com/ebike-kit/769-q128c-135mm-500w-rear-driving-ebike-hub-motor-wheel-ebike-kit.html
+ Torque arm
https://bmsbattery.com/ebike-parts/450-a-pair-of-ebike-torque-arm-parts.html

What do you think?

Thank You

Hi, perhaps a middrive would eek out a little more efficiency/range, but of course you already realize it may not be worth. The geared hub sounds like a good fit per your post.

I however, would strongly consider em3ev over bmsb when it comes to overseas vendors. As far as rpm, you may find the best efficiency with gear that goes about 10% over the max speed you are planning - of course depending on time at top speed vs stops/starts and low speed. Splitting hairs in your situation tho- I'd go for 5-10% higher gearing than desired max speed.

What type of pas does your current bike use? I guess it won't be a problem to continue it's use with a new kit. I prefer throttle only for the simplicity and the added control, but understand the appeal of decent pas.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=76519&p=1157945&hilit=+q128#p1157945
Note at the end of the first page the discussion of rear brake disc/motor clearance.

328 rpm,,, and 48v for your desired speed. Kind of a small motor to run that hard,, but since you are very light it can work ok.

It will be about 2, maybe 3 pounds lighter than a larger, stronger motor that most would advise, or I would advise if you weighed more.

I still sort of think you ought to go with a bigger geared type motor, for better durability running 25-28 mph. That size motor is better suited to 30-35 kph.

What do you mean by 40 - 45kph? The 328 rpm Q128 will cease power at 40 kph with 48v, but there won't be any significant power after about 35 kph. Those speeds will be about 10% higher with a charged battery. It would be OK for cruising at about 35 kph while pedalling steadily, though at that speed you'll be using 25 wh/mile or more, so a 400wh battery would give 16 miles (about 25 km), which is what you said you wanted.

Thank you for your replies! I can try to be more specific.

nutspecial said:

Hi, perhaps a middrive would eek out a little more efficiency/range, but of course you already realize it may not be worth. The geared hub sounds like a good fit per your post.

I however, would strongly consider em3ev over bmsb when it comes to overseas vendors. As far as rpm, you may find the best efficiency with gear that goes about 10% over the max speed you are planning - of course depending on time at top speed vs stops/starts and low speed. Splitting hairs in your situation tho- I'd go for 5-10% higher gearing than desired max speed.

What type of pas does your current bike use? I guess it won't be a problem to continue it's use with a new kit. I prefer throttle only for the simplicity and the added control, but understand the appeal of decent pas.

Click to expand...

Right now my other bike use a Bafang BFSWX02 48v code 12. It top at 36 kph without pedalling (GPS) and 45 kph unloaded. The controller is 20 amp peak I use 3-10 amp most of the time. It’s a fat bike so it’s great for winter but overkill for summer. Other than that I like the system, I can pedal when I want , use the PAS or throttle it’s really flexible. I’m looking for the same kind of system on a lighter bike. I would also like to increase the top speed (to 40-45) for a short section of my commuting where it’s easier to “follow” the traffic. My first option was the MAC from EM3EV but EM3EV doesn’t have a small pack, I don’t see a PAS in the Kit and I’m not sure it will fit a 8-speed freewheel. I would also preferably order the whole kit from one store that’s why I ended up with BMS.

d8veh said:

What do you mean by 40 - 45kph? The 328 rpm Q128 will cease power at 40 kph with 48v, but there won't be any significant power after about 35 kph. Those speeds will be about 10% higher with a charged battery. It would be OK for cruising at about 35 kph while pedalling steadily, though at that speed you’ll be using 25 wh/mile or more, so a 400wh battery would give 16 miles (about 25 km), which is what you said you wanted.

Click to expand...

So basically the 328 in a 26 inch won’t be really efficient ? I also thought of usingthe 36v 201RPM which would give m something like 266 rpm if i’m right. This should be slightly faster than the bafang code 12 on my heavier fat bike. I might be able to reach 40 kph unassisted am I right?
[*] EDIT I found the answer from mototech in another post. Should be something like that, maybe more 38 kph

motomech said:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=76519&p=1157945&hilit=+q128#p1157945
Note at the end of the first page the discussion of rear brake disc/motor clearance.

Click to expand...

I saw the post, this is basically what I’m trying to build but with the integrated controller.


Sorry my english is not perfect hope you can understand me!

Paul em3ev can make any pack you need.
Just send an email with cell type and dimensions you want.

I have to custom packs for my wifes bike 29e cells . they are great.

He also sell the 8speed Screw on type freewheel for the mac.
http://em3ev.com/store/index.php?route=product/category&path=41_56

My bike have a 9speed for 3 years now with no problems.

Erikjan said:

Paul em3ev can make any pack you need.
Just send an email with cell type and dimensions you want.

I have to custom packs for my wifes bike 29e cells . they are great.

He also sell the 8speed Screw on type freewheel for the mac.
http://em3ev.com/store/index.php?route=product/category&path=41_56

My bike have a 9speed for 3 years now with no problems.

Click to expand...

Thank You I'll contact Paul

So basically the 328 in a 26 inch won’t be really efficient ? I also thought of usingthe 36v 201RPM which would give m something like 266 rpm if i’m right. This should be slightly faster than the bafang code 12 on my heavier fat bike. I might be able to reach 40 kph unassisted am I right?
[*] EDIT I found the answer from mototech in another post. Should be something like that, maybe more 38 kph

Click to expand...

The Q128C to use is the 500 W, 328rpm @ 48V and it is very efficient(<80%). It is in effect, the same speed range as a 260 rpm @ 36V motor. This is a mid-speed range that is best for the vast majority of applications.
But it will not reach your speed goal on 36V. For that, you would have to use a 328 @36V and in a 26 inch and it is not a very efficient combination.
The solution is simple, run the Q128 328 @48V on 48 Volts. BMS Battery offers an intergrated 48V/20A battery/controller;
https://bmsbattery.com/ebike-battery/774-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
They now also offer the above with their new torque sensor system. It is so new, nobody has reviewed it yet, but I believe it uses some sort of mechanical device to improve the feel of the PAS.
https://bmsbattery.com/ebike-battery/701-48v116ah-bottle-09-panasonic-battery-torque-sensor-battery.html
That said, the 5 speed limited PAS feature of the "torque imitation" sine wave controller offers a very good PAS experience, especially considering the low-cost of the system.

philtc said:

motomech said:

https://endless-sphere.com/forums/viewtopic.php?f=3&t=76519&p=1157945&hilit=+q128#p1157945
Note at the end of the first page the discussion of rear brake disc/motor clearance.

Click to expand...

I saw the post, this is basically what I’m trying to build but with the integrated controller.

Click to expand...

As an avid cyclist with a long commute to work and family obligations, I wanted a build which would greatly speed up my journey, while allowing me to provide the same pedalling effort as before (and It sounds like the OP is looking for something along these lines). In this, it has surpassed its objectives and rides much like a normal bicycle with some added magic. With strong pedalling, my bike is quick and agile. For the most part, I can sustain 36 kph with under 250W (260RPM@48V Q128c on a 700c wheel), which allows for a much smaller battery.

With motor only, it would be disappointingly weak and wouldn't get my 175 lbs up some of the hills I need to ascend daily under any power level; add some legs and I can easily sustain 25 kph up the same hills with less than 400W motor power. Put much more than 500 W sustained and the Q128c would melt like butter.

Bottom line: the Q128c isn't for everyone, but with pedal contribution, it is highly efficient and a lot of fun to ride. For something that freewheels, can take a bit more abuse and sustain 40 kph without much pedalling, I would consider a Mac.

motomech said:

The solution is simple, run the Q128 328 @48V on 48 Volts. BMS Battery offers an intergrated 48V/20A battery/controller;
https://bmsbattery.com/ebike-battery/774-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html
They now also offer the above with their new torque sensor system. It is so new, nobody has reviewed it yet, but I believe it uses some sort of mechanical device to improve the feel of the PAS.
https://bmsbattery.com/ebike-battery/701-48v116ah-bottle-09-panasonic-battery-torque-sensor-battery.html
That said, the 5 speed limited PAS feature of the "torque imitation" sine wave controller offers a very good PAS experience, especially considering the low-cost of the system.

Click to expand...

This was the inital plan, I emailed BMS about the RPM but now i have no news... We'll see. The problem with the 09 case is it won't fit my frame

molybdenum said:

Bottom line: the Q128c isn't for everyone, but with pedal contribution, it is highly efficient and a lot of fun to ride. For something that freewheels, can take a bit more abuse and sustain 40 kph without much pedalling, I would consider a Mac.

Click to expand...

The reason for the 40 kph without much pedalling is because i have a 42t sprocket I'll have to change it if I want to be able to pedal at 40 kph. Otherwise I pedal most of the time and i cruise around 30 kph.

Quick question, It's might come out of nowhere but would it be possible to use the cyclone mid drive with the BMS battery integrated battery/controller ? that would give me around 800 watts peak and if I want to use more power later I could put back the stock controller with a better an bigger battery.

http://lunacycle.com/motors-and-kits/mid-drive-kits/cyclone-mid-drive-3000-watt-planetary-kit/
https://bmsbattery.com/ebike-battery/774-48v116ah-case-08-bottle-panasonic-battery-pack-battery.html