Bafang “GVT” (internal gearing)

[Chazmo]

Hi folks,

I’m wondering if anyone has used Bafang’s internally geared hub (IGH) products? These apparently shift based on wheel-spin rates and are not controlled by the rider, i.e., there’s no gear shifter. I’m curious about the riding experience of using an e-Bike without a gearset/derailleur… Bafang calls this “Gear Variable Transmission,” as described here: https://bafang-e.com/uploaded/news/202405130108276816.pdf

If this has already been discussed, I apologize. Please point me in the right direction...

Currently, there’s a rear hub motor that includes a 2-speed GVT (a.k.a. “H720”). And there’s a 5-speed(!) rear hub (“G500A”) which is for mid-drive applications.

Frankly, a 5 speed sounds really cool and I could see something like that being sufficient for a fairly natural pedaling experience and it sounds really exciting (even though I’m wary of automatic shifting). I think this 5 speed is fairly new and I doubt anyone has built a bike around it yet. But, the two-speed transmission has been around a while (I think). Has anyone used it? I’m finding it difficult to imagine how a two-speed would give as good an experience as my 9-speed cassette/derailleur gear system does.

 

[Marquezdl]

Actually, there is a page on the Bafang website for the 2 versions of the Bafang Automatic Gear Hub

Home

Bafang description

bafang-e.com

2 versions
The RG A310 (3 speed)
The RG A510 (5 speed)
They are apparently aiming the 3 speed variant at city-commuter-recreational ebikes
and the 5 speed at maybe commercial uses.
the 3 speed is listed as 1.7Kg.
the 5 speed is listed at 3.7 kg. Thats a pretty hefty load for a non-commercial ebike

the 3 speed is extremely interesting to me, it could be retrofitted to a nice steel frame I have. This seems to negate some of the advantages that mid-drive units have over standard hub type motors.
I too am anxious to find out how well they work in the real world.

 

[Chargeride]

Im confused, which is the actual motor gears and the pedalling gears, if any or not.

 

[PCeBiker]

Im confused, which is the actual motor gears and the pedalling gears, if any or not.

The H720 is a complete geared hub motor that has two speeds.

The 3-speed and 5-speed (A310, A510) are just geared hubs, (like a IGH Rohloff) and I believe that there is only room for a single sprocket on the axle.
HOWEVER, that single sprocket is actually geared (automatically and mechanically using centrifugal force I think?) so the mid motor, and the rider pedaling, that are connected to the hub actually see 3 or 5 gears.

When the hub switches gears, both the motor and rider use that new gear ratio.

It's all automatic with no control cables or wires, so less crap to fail or go out of adjustment.
(I know that the shifting mechanism for a Rohloff has push/pull shifter cables that are kinda fussy and proprietary.)

I have no idea how reliable they are, and I'm sure someone will hook it up to a 250 Nm 2000 Watt motor, and wreck the geared hub.

Then they'll say the hub is crap.

 

[PCeBiker]

Its basically a rear wheel hub with the electric motor built into the hub, and there is also a 3 or 5 speed planetary gear transmission built into the hub.

I'm pretty sure (but not positive) that the geared hub MOTOR is only available as a 2-speed.

The 3-speed and 5-speed are just geared hubs without the motor.

I think BAFANG should build a 5-speed geared hub Motor.

I don't care if it weighs 3.7 kg.
My ebike already weighs over 80 pounds, what's another few more pounds.

 

[Marquezdl]

I'm pretty sure (but not positive) that the geared hub MOTOR is only available as a 2-speed.

The 3-speed and 5-speed are just geared hubs without the motor.

I think BAFANG should build a 5-speed geared hub Motor.

I don't care if it weighs 3.7 kg.
My ebike already weighs over 80 pounds, what's another few more pounds.

You, my friend are totally correct! I on the other hand leapt before I lookt! The 3 and 5 speed hubs are simply auto-shifting IGH hubs…no motors.
the 2 speed you quoted is an integrated motor and 2 speed auto shifting transmission in the rear hub. as a city biker, that hub is extremely interesting to me. I will be anxiously awaiting the first reviews of this system on a real bicycle being ridden in the real world. This integrated motor/transmission is available in at least 3 flavors according to Bafang’s website: H720, H710, H700. They have diffferent weights, power and torque outputs.

 

[PCeBiker]

This is a link to the service manual,..

https://bafang-e.com/uploaded/manual/BF-UM-C-RM%20G06A2.750-D-EN.pdf

I doesn't even mention how many gears it has ??
It comes with this description and motor code though,..

I think the code means that it's a standard G06 series 750 Watt fat motor (with all the related dimensions), and the "A2" part means that it's a 2-speed Automatic motor?

 

[PCeBiker]

@Marquezdl are you, me, and @Chazmo seriously the only people on the planet that want a 5-speed automatic geared hub motor?

So what if a 5-speed geared hub Motor would weigh even more than the 5-speed geared hub.

It's a motor with a battery connected to it.

You don't have to install the motor in the middle of the bike if you're just riding on the road and not bombing down the side of a mountain trail.
There's "Specialized" equipment designed for that purpose.


I wouldn't be using the motor to try and go 80 mph, I just want more torque and efficiency at lower speeds.

 

[Marquezdl]

The idea of an IGH, which I have quite a lot of experience riding, having owned and ridden both a Rolhoff and a Shimano Nexus 8 is, being combined with a modestly powerful motor in the rear hub is something I have long desired.
I am not really a fan of mid-drive ebikes. I have owned 2 very nice specialized ebikes, both mid drives, both excellent for what they are, albeit quite pricey. However I sort of “moved on” from derailleurs and freewheels/cassettes in the early 90’s when I built my first set of bicycle wheels using a Phil Wood flip flop hub with a single speed freewheel and a fixed cog. After that I decided that I wanted to try IGH bicycles. So starting in the early 2000’s I got a custom steel frame with a Rolhoff hub. It is designed for light touring and randonneuring. It’s excellent for those purposes and I put well over 10K miles on that Rolhoff and never even had to change the chain. I just kept it clean and lubed and adjusted the tension a couple times. Then I got a 2nd steel frame with a Shimano Nexus 8 for around town…again a clear winner for me. Both of these steel frame IGH bikes have rim brakes, and that is the only reason I haven’t set one up as an ebike with a motor in the front wheel.
This Bafang 2 speed motor/IGH sounds like a very good option to upgrade my 8 speed internal hub to a 2 speed IGH/motor for riding around town!

 

[BlackHand]

ADO Air 30: The 1st Integrated Auto 3-Speed E-Bike

3 Speed Integrated AutoShift Motor | Anti-Theft GPS | Portable Battery | Carbon Belt | Torque Sensor | Check out 'ADO Air 30: The 1st Integrated Auto 3-Speed E-Bike' on Indiegogo.

www.indiegogo.com

 

[PCeBiker]

ADO Air 30: The 1st Integrated Auto 3-Speed E-Bike

3 Speed Integrated AutoShift Motor | Anti-Theft GPS | Portable Battery | Carbon Belt | Torque Sensor | Check out 'ADO Air 30: The 1st Integrated Auto 3-Speed E-Bike' on Indiegogo.

www.indiegogo.com

That's not my kind of ebike.

I wonder if I can buy just the motor or wheel?

I want to install it on my full suspension fat-bike.

 

[Marquezdl]

Ai am hoping someone will do a ‘kit‘ version so that nice bicycle frames can be converted to ebikes. especially if the 3 speed transmission is used.

 

[PCeBiker]

Ai am hoping someone will do a ‘kit‘ version so that nice bicycle frames can be converted to ebikes.

I'm thinking drop-out spacing might be and issue with older steel frames?

These are the drop-out spacing (OLD measurement) for the 3 current two-speed automatic hub motors,..

I can't seem to find any information about the axles?

especially if the 3 speed transmission is used.

That would have to be a mid-drive motor to drive the geared hub, but it would be a single gear or belt drive.



So Bafang needs to build an automatic 3-speed IGH hub motor.

One version to fit old-school bicycles, and another version to fit my fat e-bike frame.


We need to start a petition.

 

[Marquezdl]

Cold setting the dropouts on my steel Davidson shouldn’t be a problem. Getting disc mounts added to the frame might be a bit more work, but the real problem is stripping off the powdercoat to allow brazing on disc mounts fr and rr.
Of course ALL that is contingent upon Bafang coming out with a kit for updating old bicycle frames to modern urban ebikes!
Yep, I agree, a Petition is in order!