Mini comparison DD vs Geared

[MikeSSS]

A friend got a geared hub kit from Luna. The front, geared hub is about the same size as my DD front Aotema hub, but is probably lighter. Both are brushless, the GH has sensors, the Aotema is sensorless. Old rigid mountain bikes, with road tires and spring seats, were used for both hub motors.

Controller size is smaller for the geared hub, GH, it does not have an on/off switch, but there is a power button on the "dashboard". The Aotema's larger controller does have an on/off switch but does not have a "dashboard". The GH is made for 48v, the Aotema is made for 36v but will run well on 48v too.

On the road, both using Luna Shark, 48v, 14Ah, GA cell batteries: both bikes had about the same acceleration and top speed. There was some gear whine from the GH and sometimes some harmonic noise from the DD. Neither was loud, not even close. But they are sort of noticeable if you sneak up and leach somebodies wheel.

Low speed use was very controllable for both bikes, cogging rumble on the Aotema at low speeds is more noticeable when using 48v as compared to 36v, above perhaps 10 mph cogging is not apparent. I did not notice cogging rumble from the GH. The GH freewheels when electric power is not used, the Aotema DD does not freewheel but the drag during no e-power pedaling is not too bad.

With a 36v SLA gel cell battery on the Aotema powered bike and with the Luna 48v Shark on the GH bike, the GH bike had better acceleration and top speed. This was expected, but was not as big a difference as anticipated.

No climbing was done with either bike. Pub visiting was done though and either bike will get you to the calamari in fine style.

Well that's it, GH vs DD turned out to be sort of "six of one and a half dozen of the other".

 

[spinningmagnets]

Thanks for the honest review...many others have reported the same...

 

[Ykick]

I’ve been lucky to ride test many different drive setups over a consistent daily commute for almost a decade. Using identical controller programming and only swapping motors between DD/GH, Watts is Watts…

The touted “efficiency” of BBS02 also left me a little disappointed in the real world. It’s gotten somewhat better with addition of a smaller chainring but it still isn’t that much noticeably better than the 2 flavors of hub motor. It will climb steeper hills more efficiently but average riding it does not make a huge difference.

At the beginning and end of the day, 20-25 MPH requires 400-600 Watts.

There are many factors which can and will influence drive selection. Ease of assembly and servicing as well as weight and distribution to name a few. However, “efficiency” is probably the lowest on my list of practical considerations for a choice of drive system.

 

[dogman dan]

What I've said a lot too. Once going, on a longer open road cruise, all types will end up using about the same wattage to go 20 mph. That's assuming the bikes are very similar, so no changes in drag, no changes in weight, and so on. and all 26" wheel. This is just laws of physics sort of stuff. X weight and Y drag ends up always needing Z wattage. At speed and loaded moderately, all types operate with great efficiency.

But the differences become very apparent when you overload and climb hills, or you get into stop and go city riding.

mid drive can haul the most weight up a hill efficiently, because it can gear down.

Geared hub motor easiest to ride in the city efficient, no need to shift down at every stop for max efficiency like a mid drive, but still takes off from a stop good.

But go to 20" wheel, and a lot of the difference starts to matter less and less. Because now the hub motor did gear down.

 

[MikeSSS]

Luna's geared hub kit had plenty of wire length, a lot more than needed for a simple rigid mountain bike. The connectors could only plug in correctly and appeared to be water resistant. A potential problem could arise from attempting to plug together dis-similar connectors and subsequently bending pins, this is a problem for far sighted old guys. No instructions were included, this would be a large problem for many people, people who haven't done this sort of thing before.

Corpus Christi has a lot of street paving problems, caused by the swelling clays beneath the surface. Riding ebikes at 15 to 20 mph gave a lot of harsh jolting to the riders, the batteries, controllers, hubs, wheels, bikes and racks. My next build will be a mid drive on a full suspension bike. That will give me the climbing ability needed for San Antonio hills and a good ride for Corpus Christi streets.

When you're riding an ebike ... every day is big ring day!