Bionx D vs Falco Hx. Is Bionx more efficient?

Mike leroy

Active Member
Upshot: The center-drive generates about three times the amount of hill-climbing power, which is very surprising!

Bionx D generates 50Nm torque for 500W at 4kg
Falco Hx generates 80Nm torque for 1000W at 7.5 kg

Should one expect Torque to be linear with respect to watts?

If Falco is as efficient as Bionx, should falco generate 100Nm of torque, rather than 80?
Or would a 1000W Bionx also only generate 80Nm of torque?

I have only considered mid-drives up to this point. The 8Fun BBS02 torque is not linear. Falco and 8Fun are similar. So, my guess is Bionx and Falco are similar. Mid-drives produce more torque per watt. The unknown is how much torque a 1000W 8Fun would produce.

In this case, the 350W 8Fun BBS02 center-drives produces the same hill-climbing torque as a 1000W Falco hub motor.

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http://ridebionx.com/technology/motor-technology/
  • Nominal power: 200W (AU & UK), 250W (EU), 500W (NA)
  • Torque: 25/50 Nm (18.4/36.9lb-ft)
  • Weight: 4.0kg (8.8 lb)
  • Brushless, gearless
  • Generate mode for energy recuperation
  • Integrated torque sensor
http://www.falcoemotors.com
Motor
Motor 7.5 kg
Rated Power 1000 W
Peak Torque 35 to 80 Nm
Speed Limit 27.5 kph (Europe)
32kph (US)

8Fun BBS02 mid-drive is not linear. Doubling watts only increase torque by 50%.
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Data
Position Mid Motor (Link Removed - No Longer Exists)
Construction Geared Motor
Nominal Voltage 36/48 V
Power 250-350 W
RPM 70-90
Torque 80 Nm
Efficiency ≥ 78 %

Core Data (Link Removed - No Longer Exists)
Position Mid Motor
Construction Geared Motor
Nominal Voltage 36/48 V
Power 500-750 W
RPM 110-130
Torque 120 Nm
Efficiency ≥ 78 %
 
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Ann M.

Well-Known Member
Upshot: The center-drive generates about three times the amount of hill-climbing power, which is very surprising!

Bionx D generates 50Nm torque for 500W at 4kg
Falco Hx generates 80Nm torque for 1000W at 7.5 kg

Should one expect Torque to be linear with respect to watts?
Interesting observation: Part 2 of a YouTube presentation of hub motor vs. middrive showed the middrive weaker without pedaling:


This seems to contradict some of the data you collected, so I am curious and confused since the rhetoric generally passed around is that mid drive motors have more torque, thus better hill climbing ability.
 

Mike leroy

Active Member
I would appreciate any advice on which hardtail bicycle frame would take the 1.5kW Falco motor with a SRAM X01, 11 speed cassette. I was told the total OLD width is probably 150 to 200mm. Also, is limited to a single gear, depending upon the actual OLD (Over Locknut Dimension) width.

I learned that I could achieve 30mph speeds on a 10% grade with the 1500W Falco. Competing with cars in the ride-share lane is possible with Powerful performance of this caliber. My hill offers no bike lane, so the 1.5kW is attractive.
 
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Mike leroy

Active Member
Interesting observation: Part 2 of a YouTube presentation of hub motor vs. middrive showed the middrive weaker without pedaling:


This seems to contradict some of the data you collected, so I am curious and confused since the rhetoric generally passed around is that mid drive motors have more torque, thus better hill climbing ability.
The issue you raise is the same old issue about standards for eBike comparison. Not enough information is provided for consumers to make valid comparisons. On my last run to my local store, I spoke with a former eBike owner. He is very fit. The eBike only helped for short trips, not commutes over 5 miles. He felt A 10kW Honda PCX scooter is most appropriate for suburban hills in the 10% to 15% grade range. The Honda PCX is less expensive and twice as fast as the bikes in the video.

The lack of comparison standards made the Honda PCX an easy choice.

Regarding the video:

The point of the video has no practical value. In other words , it is useless information. Those types of bikes are designed for pedaling, not as suburban scooters. Those HPC bikes are poor scooters, at that.

The motor construction affects performance, e.g., windings, type, etc.... Watts are only a single representation of power. Evidently, the 1000W Falco is slower than the 750W Falco for hill climbing, because the 1kW is designed for a different purpose, I.e., cargo.

The danger of video is essential information may not be presented. What may seem compelling on film for a particular instance, may not be a general explanation in all cases. All detailed information must be referenced, which is awkward to present in video.

The major benefit of mechanical advantage of a mid-drive using the gear system was dismissed. Not mentioning the whole point of a mid-drive is extremely misleading. 95% of the U.S. population will be confused by video like that. The exact purpose and limits were irresponsibly omitted. If you present a very narrow viewpoint, then explicitly qualify the conditions under which an example applies to.

Videos like that scare me because they over-simplify reality. People might get the mistaken impression that it is safe to take a powerful bike into traffic. Details such as chain strength, battery distance, etc...., need to be made explicit. What if the battery power diminishes or dies in traffic at 35mph? The rider could get rear-ended by a 4,000 pound car.

Even the specification data sheets are not enough to draw conclusive conclusions. I do not think the scant information that I collected is adequate. A great deal of information needs to be gathered and processed in an intelligent manner.

If you look at a Strava map for my road, the glaring fact is that riders avoid it. Bicycles are poorly suited to the road, for many reasons that are not easily simplified and packaged in video. Not the point a vendor wants to make about his product, regardless of how interesting or insightful about an isolated, detached aspect.

I still prefer to run two miles to the store and carry groceries up the hill. I remain humored by the bicyclists who refuse to race me up the hill. Bicyclists have all the advantages over a runner.
 

Ann M.

Well-Known Member
Thanks, @Mike leroy , I actually agree with you on the specious comparison of the two bikes in that video. It would have made more sense to compare them while the rider was pedaling since they weren't designed to be scooters.