Mid drive and cadence upper limit (top end).

Trail Cruiser

Well-Known Member
Hi Court (administrator), I always hear you say that the mid drives are limited by the assist cut off at a not-so-high cadence RPM, so you have to upshift if you want to go faster . Bosch used to have favorable feel since the cut off is 106 RPM so you can pedal fast enough. The assist cut off in Yamaha, Brose, and other popular OEM brands are in the 80-90's RPM. However, things have changed now and you should really check it with a cadence meter especially when you tested the recent Giant ebikes since they now use the new Syncdrive that has higher cadence cut off of 110-120 RPM.

This is from the E-mountainbike magazine: " The pedal-assist on the SyncDrive Pro works in the three strongest support modes with a cadence up to 120 rpm, and up to 110 rpm in the lower two modes. This is another diversion from the Yamaha PW-X, which only supports up to 120 rpm in the most powerful pedal-assist mode." http://ebike-mtb.com/en/first-ride-giant-full-e-0-sx-pro-new-syncdrive-pro-motor/

So your preconceived idea on Mid drives does not apply anymore to this newer models.

By the way, The newer Giant ebike has a cadence meter on it's display panel so there is no excuse not to check it.
 
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RoyL

Active Member
Also think the BBSxx range have a high natural cadence, far too high imo.

No matter what pas level you`re in you get the impression you`re always trying to keep up with the motor.
 

Trail Cruiser

Well-Known Member
Also think the BBSxx range have a high natural cadence, far too high imo.

No matter what pas level you`re in you get the impression you`re always trying to keep up with the motor.
In the Bafang BBSxx, I actually like that it is not limited by the motor cut off at high cadence, thereby providing a more natural feel. My other bike is a hub drive and another is a non-electric powered, both I use as my basis for comparison. If I can spin above 120 (esp when I accelerate aggressively), then I should be able to do it also on a mid drive.

I also ride a TranzX mid-drive that has a cut off ranging from 80 RPM at PAS 1 to 100 RPM at PAS 4. This makes me think that the BBSHD is the VTEC among the mid drives out there.
 
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flymeaway

Well-Known Member
Hi Court, I always hear you say that the mid drives are limited by the assist cut off at a not-so-high cadence RPM
??????? You can program the controller to do just about anything you want. As I recall...from memory the upper (speed) limit is 99, can't remember if it's KPH or MPH, but either way you'll be moving right along. Perhaps I'm not pedaling at 120 RPM (cadence) but I regularly go well over 100 RPM (cadence) when climbing steep grades.

Court J.
 

Trail Cruiser

Well-Known Member
??????? You can program the controller to do just about anything you want. As I recall...from memory the upper (speed) limit is 99, can't remember if it's KPH or MPH, but either way you'll be moving right along. Perhaps I'm not pedaling at 120 RPM (cadence) but I regularly go well over 100 RPM (cadence) when climbing steep grades.

Court J.
I posted this addressed to Court Rye the administrator since I noticed that whenever he reviews a OEM mid drive, he always mention about the high cadence limitations, and that the Bosch has a higher top end compared to other mid drives. This old notion does not apply anymore to newer OEM mid drives. Bosch has an indicated top end of 106 RPM, however, the newer Yamaha based Synchdrive has a top end of 110-120 RPM.

The Bafang BBSHD is a whole different league, it has a top end of 150 RPM at 48 volts (130 RPM at 36 volts). A well trained bike sprinter also has does 150 RPM clown pedaling at its peak performance. Maybe, Bafang took into consideration that well trained athletes may also be using their ebikes?
http://image.dhgate.com/0x0s/f2-alb...t-sale-b-bike-new-design-good-quality-48v.jpg

And that may be the reason why Bafang won in the Ebike endurance race in Germany?

 
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Trail Cruiser

Well-Known Member
Where did you find this spec.? Just curious.

Thanks,

Court J.
You did not see the link I posted.
http://image.dhgate.com/0x0s/f2-alb...t-sale-b-bike-new-design-good-quality-48v.jpg

and here; " The RPM is increased to 130-150RPM from the BBS02 750W which ran at around 120RPM which is way faster than you could ever pedal"
https://electricbike-blog.com/2015/...2ish-that-fits-a-68-120mm-bb-with-giant-fins/

Bicycle sprinters are whole different animals, they can clown pedal to rapidly accelerate to 150 RPM (unheard of to the regular cyclists!).
http://www.active.com/cycling/articles/how-great-bike-sprinters-are-made

Here is a video just to give a general idea of how fast the cadence of these sprinters are.
 
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flymeaway

Well-Known Member
You did not see the link I posted.
Are you referring to motor RPM or pedaling cadence RPM? Your posts reference both.

For instance: " The RPM is increased to 130-150RPM from the BBS02 750W which ran at around 120RPM which is way faster than you could ever pedal"

I'm honestly not certain how to interpret this quote since pedal cadence is entirely dependent upon gearing.


Thanks,

Court J.
 

Trail Cruiser

Well-Known Member
Are you referring to motor RPM or pedaling cadence RPM? Your posts reference both.

For instance: " The RPM is increased to 130-150RPM from the BBS02 750W which ran at around 120RPM which is way faster than you could ever pedal"

I'm honestly not certain how to interpret this quote since pedal cadence is entirely dependent upon gearing.


Thanks,

Court J.
The "RPM" is the crank RPM after the motor goes through the gear reduction process. The crank RPM is the same as the pedal RPM or cadence. The motor usually spins at 2-4 thousand RPM and needs to be geared down to match the rider's cadence.

Road cyclists almost always has cadence, besides the road speed on their display monitors.

If you have bafang mid drive then this is not an issue since your cadence is usually below the top end of the motor. However, on the old yamaha, brose, impulse their top end are in the 80's RPM and if you pedal faster than 80 RPM, the motor assist is not there anymore. You already surpassed the top end of the motor.
 
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MLB

Well-Known Member
If you are a regular rider that understands and practices spinning, 150 isn't "that" far out there.
I regularly hit 130 when sprinting and can spin 140 but not with any power.
I'm 57 and 30lbs overweight but in good cardio shape. Point being I'm not exceptional in any way. ;)
 

Trail Cruiser

Well-Known Member
If you are a regular rider that understands and practices spinning, 150 isn't "that" far out there.
I regularly hit 130 when sprinting and can spin 140 but not with any power.
I'm 57 and 30lbs overweight but in good cardio shape. Point being I'm not exceptional in any way. ;)
Spinning on an exercise bike is different but it is a good exercise anyway. On a running bicycle you also have to put a lot of load to it in order to maximize your accelerating potential.
 

JRA

Well-Known Member
The biggest cause of ghost pedaling is inadequate high gear ratios on e bikes. Most all the speed pedelecs have at best 115" high gears which spin out at around 25mph and beyond that the efficiency of human pedaling effort drops dramatically. If you want to spin at 140 rpms fine but most people are more comfortable and efficient in the 80-100 rpm range over long distance and in order to have effective human pedaling input at 45 kmh/28mph you need at least a 130" gear or a 52/11 on a 28"er. More is even better as you can apply more pressure at the pedals to relieve the motors assistance even more if you want to exert more energy and stay on top of the motor.
 

RoyL

Active Member
AKA, "clown pedaling".
very true Thomas,

i have the BBS02, very difficult to go out for a leisurely ride, the system always seems to want to get up to that 120rpm area, pulling back the pas level slightly helps,

i think that`s why the BBS range are more demanding on the battery as opposed to the torque motors
 

Trail Cruiser

Well-Known Member
very true Thomas,

i have the BBS02, very difficult to go out for a leisurely ride, the system always seems to want to get up to that 120rpm area, pulling back the pas level slightly helps,

i think that`s why the BBS range are more demanding on the battery as opposed to the torque motors
I would guess Bafang has considered to accommodate the possibility of athletes who might ride electric bikes and spin to above 120's (once in a while). Just like a car with the capability to red line your engine, but not intended to be used all the time (only when really needed).
 

Thomas Jaszewski

Well-Known Member
Please see attached link.
http://image.dhgate.com/0x0s/f2-alb...t-sale-b-bike-new-design-good-quality-48v.jpg
In other countries they use 36 volts and detuned controllers to comply with the local laws.
Be careful drawing conclusions from Bafang posts. Bafang's specs as published should not be considered as gospel. Yes there are 36V models but not 36V BBSHD. Controllers are not detuned. They are quite different between products. Different FET's and internals. I have several including unpotted, and have owned most if not all versions. I currently ride an EU version.
 

Thomas Jaszewski

Well-Known Member
very true Thomas,

i have the BBS02, very difficult to go out for a leisurely ride, the system always seems to want to get up to that 120rpm area, pulling back the pas level slightly helps,

i think that`s why the BBS range are more demanding on the battery as opposed to the torque motors
I think that in the USA the market is very different among BBSxx buyers. The market is also very different between DIY and OEM bike buyers. In my opinion and experience the BBSHD is better suited to those who want speed and power and are more inclined to use more throttle. The BBS02 better suited to the more athletic and serious rider using the gearing available. They are VERY different motors. The BBSHD can be left in 4th or 5th of seven and just ridden as a single gear. Take offs in gear with throttle are no issue and you have a 26MPH single speed. Do that with any regularity and weight on a BBS02 or 01 and you'll soon be being a new motor. It's interesting that you find the 02 as being similar. I'd guess you are more of a serious bike rider and the torque versions of mid drives would be your cuppa.
 

Trail Cruiser

Well-Known Member
Be careful drawing conclusions from Bafang posts. Bafang's specs as published should not be considered as gospel. Yes there are 36V models but not 36V BBSHD. Controllers are not detuned. They are quite different between products. Different FET's and internals. I have several including unpotted, and have owned most if not all versions. I currently ride an EU version.
Here's another site with the article.
https://electricbike-blog.com/2015/...2ish-that-fits-a-68-120mm-bb-with-giant-fins/